# Regarding 2 spectacular Kelly controller failures



## Tesseract (Sep 27, 2008)

very important issue, ZenDaddy. I suggest the following setup: a manual battery pack disconnect where a rope connects to one of a pair of appropriately rated "Anderson" connectors while the other one is fixed to the chassis. During an emergency you pull the rope to yank the two connectors apart. Granted, this is brutal on the connectors, but so is a series wound motor going full bore unloaded (explodes from centrifugal force).


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## ZenDaddy (Jul 22, 2008)

Tesseract,

Thanks for the reply. I do (thank god!) have a choke cable connected to my main cutoff and utilized it very quickly when the motor ran away. Saved my motor.


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## frodus (Apr 12, 2008)

Exactly as I said in another thread



> Originally Posted by *frodus*
> _just because your controller failed, doesn't mean that there wasn't a faulty installation, bad battery issue, motor issue, etc. Sure, its a simple setup, but if you didn't install something like a prechare resistor, or a shotkey on the contactor, it could have caused problems. _


_Slamming those caps with full voltage is NOT going to help their life. Thanks for posting this. I think alot of people don't realize what it does, then blame the controller manufacturer for a faulty controller. Its neither here nor there._

_Its one reason our controller at Synkromotive has a built in precharge resistor._


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## Qer (May 7, 2008)

frodus said:


> _Its one reason our controller at Synkromotive has a built in precharge resistor._


Yup. Sounds like a very good thing to me. On the other hand, one could ask why the manufacturers don't include a precharge circuit to begin with. I mean, no matter whose the fault is the risk is that it gives a bad rep when the controller dies...


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## ZenDaddy (Jul 22, 2008)

Qer said:


> Yup. Sounds like a very good thing to me. On the other hand, one could ask why the manufacturers don't include a precharge circuit to begin with. I mean, no matter whose the fault is the risk is that it gives a bad rep when the controller dies...


 
Agreed! It would also be nice if they explained in the manual exactly why the precharge resistor is required and give comprehensive "startup" sequence instructions. In both above instances, the resistor was there and we thought we had it right. Followed the recipe without understanding the process so to speak.

Steven Li stated in another thread that Kelly was working to resolve "no precharge" failures. I'm sure (I hope) they will succeed. In the mean time perhaps we can help people like me who didn't completely understand the importance of precharging the controller to avoid the potentialy dangerous failure to begin with.

Regards
Michael


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## ZenDaddy (Jul 22, 2008)

HEY!

I just realized that I've been promoted from "junior member" to "member"!

I feel special!

lol


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## frodus (Apr 12, 2008)

Qer said:


> Yup. Sounds like a very good thing to me. On the other hand, one could ask why the manufacturers don't include a precharge circuit to begin with. I mean, no matter whose the fault is the risk is that it gives a bad rep when the controller dies...


I honestly don't know. I think the zilla has one. It also checks that the voltage level on the caps is at pack level before closing the contactor. Both ours and theirs control the contactors intelligently. 

They don't include it because it needs microprocessor control and extra parts (a FET turns on the precharge, micro controller checks voltage, then another FET turns on the contactor when all systems are go).


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## ZenDaddy (Jul 22, 2008)

NOTE! a reply from Kelly.

Mike,

So far I got 3 reports about the failures of isolated controller.

Actually the controller can survive the case, if 12V supply is turned on. We tested the case with thousands cycles.

But with 12V off (so micro and driver circuit off), switch on and off battery can be an issue, I guess. I have informed the factory about it. We are resolving the problem. The situation wasn't expected at design phase. We should have solution soon. (Because the micro and driver circuit aren't powered, so protection circuit doesn't work...It's relative hard. We have to use passive circuit to protect it).

The controller can be hurted by the abrupt power up, and be killed by driving after that, I guess.

You may see right now our focus is on how to protect against those abnormal usage. We have all input signals protected against 200V. Right now we need to protect against abrupt battery with micro off. That can take some time.

Thank you very much for your info.

Steven


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## frodus (Apr 12, 2008)

What we need to put together is a self contained contactor controller with precharge, Diode and a timer. Ignition inputs, safety interlocks, aux input, and a dedicated 12V supply source off the DC-DC converter battery. Totally self contained and designed to protect the controller. Seems that "abnormal" useage is becoming more and more with all of the conversions that are out there.

It SHOULD be, Ignition on connects precharge to the controller. Once controller voltage is at pack voltage, it checks that the interlocs are engaged and that the car is not in gear, and that the brakes are on, throttle is not pressed...etc. Then it engages contactor and controller is online. If interlock, aux etc becomes disabled, it drops contactor immediately.


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## ZenDaddy (Jul 22, 2008)

Maybe an educated member could describe, in laymans terms, the importance of precharging the controller? Also, describe the damage and danger possible when this critical function of a precharge circuit is not fulfilled?


Thank you!

Michael


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## Qer (May 7, 2008)

ZenDaddy said:


> Maybe an educated member could describe, in laymans terms, the importance of precharging the controller? Also, describe the damage and danger possible when this critical function of a precharge circuit is not fulfilled?
> 
> I would try, but I have not earned the credibility.
> 
> ...


There's one kind of component in electrical systems that's called a capacitor. It's like a very small, but strong battery and as such it tries to compensate for voltage changes. Typically a controller has a big pack of such on the input to even out the current peaks so the current from the battery pack is on a constant, stable level instead of chopped up like wild. Think of it as the big water reservoirs that makes it possible for you to take a shower even when the neighbor flush the toilet.

Now, the problem is when you start up the controller and the capacitors are all empty. When the contactor switches on, the capacitors will try to charge up to the same voltage as the battery pack and it's in their nature to do so as fast as they possibly can, which means that they more or less short circuit everything which leads to a horrible current spike. That spike isn't good for the contactor (it will arc) and it's not very good for the capacitors as well so odds are that the life length of the capacitors, the contactor and other components involved will be seriously degraded by this current rush.

Insert precharge resistor. A resistor will limit the current (like a valve in a water pipe) which will mean that the capacitors trickle charge over time (a few seconds is very much longer time than almost instantaneously) which will prevent the arcing in the contactor and also remove the stress from the rest of the circuit which will mean that the controller will (hopefully) live a long, happy life instead of a short, extremely stressful one.

Precharge resistor is a VERY good thing, no matter what controller you have. Get one.


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## Tesseract (Sep 27, 2008)

ZenDaddy said:


> Maybe an educated member could describe, in laymans terms, the importance of precharging the controller? Also, describe the damage and danger possible when this critical function of a precharge circuit is not fulfilled?..


Qer explained the situation well; I'll just add some technical info...

The current that "rushes in" when the contactor is closed without pre-charging (called, appropriately enough, "inrush current") can be estimated by dividing the pack voltage by the capacitor bank's "ESR", or equivalent series resistance. Good quality electrolyics of the size typically used in this application have an ESR, each, of around 0.05-0.5 ohms. A bank of 10 in parallel will look like a 0.005 to 0.05 ohm resistor to the battery pack when the contactor closes. If the battery pack is 120V then the peak inrush current (ignoring Peukert effect, battery cable resistance, etc.) could be as high as 24,000A. This amount of current, if it doesn't cause the conductor to outright vaporize, will make it "jump". That's what hurts the electrolytics: the foil electrodes end up rubbing against each other which could wear through the thin oxide dielectric causing them to short out.

Another problem is that this amount of current is more than enough to spot weld the contactor's contacts together - oops, now you can't turn the darn thing off!

That said, the pre-charge time certainly doesn't need to be 20-30 seconds. As rfengineers noted, 2-3 seconds is more than enough to protect the contactor, capacitors, PC board foil, etc... The value of the pre-charge resistor is not terribly critical - anything from a few ohms to a few hundred ohms might be specified - but it will need to be capable of handling the peak charging current as determined by its value and the pack voltage.


Even more technical stuff: E.g. - a 300 ohm resistor and a 120V pack will result in a peak charging current of 0.4A (a far cry from 24,000A, eh?) and a peak dissipation in the resistor of 48W. Now, how long do you have to wait before closing the main contactor? To answer that you have to know the amount of capacitance that needs to be charged up - a tidbit of information that probably isn't supplied by the manufacturer. If you do know it then the rule of thumb is that a capacitor charges to 99.3% of the applied voltage in 5RC, where R is in ohms, C is in farads and time is in seconds. Thus, let's assume the controller has 3300uF of capacitance inside it:

5*(300 ohms)*(3300*10^-6 farads) = 4.95 seconds

You need to wait 5 seconds before closing the main contactor (shorting out the pre-charge resistor) in this setup. What happens if you wait, say, 4 seconds? Well, at that point the capacitors are approximately 98.2% charged - sounds close enough, right? Well, let's figure that out. The battery pack is 120V, so the capacitors are charged to 0.982*120 or 117.84 at 4RC, the difference in voltage between the two is a mere 2.16V but that still results in a peak current of 432A across the 0.005 ohms of ESR! This is very hard on the contactor's contacts - to get a decent life out any mechanical switch you don't want to operate it while carrying that much current, especially not DC current which sustains an arc much more easily once initiated.

A pre-charge current of 0.4A is awfully low and the potential for damaging the contactor or the controller's internal circuit board/capacitors is too high if you have to wait 5 seconds between pre-charging and closing the main contactor. With a precharge resistor in ohms equal to the battery pack voltage the peak current will be 1A - hardly any difference to 0.4A - and the capacitor bank in the above example will be fully charged in 2 seconds. The peak power dissipated in the resistor is 120W, as compared to 48W, but since that power declines exponentially over 2 seconds a 10W "sand-filled" resistor will suffice.

Hope you folks didn't fall asleep


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## TheSGC (Nov 15, 2007)

I just have been waiting about a minute for my controller to precharge. Or longer. I am in the "EV not close to being done, but can drive" stage and I use my circuit breaker as a cutoff switch. So I unplug the EV from the wall, flip the breaker on and then go back and pack up my chargers and cables.


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## JRP3 (Mar 7, 2008)

In a thread on the EVDL I asked about the need to switch the precharge resistor on and off. Alltrax does not show it being switched, just always inline. There were differing opinions, but one person suggested that the life of the caps might actually be extended by having them always powered, "fully formed" was the phrase I believe, and therefore the precharge resistor did not need to be switched. It does draw a small amount of power of course so if the vehicle were sitting for weeks it might drain the batteries. I have not noticed significant drain on my 48 volt setup after a week or so of sitting.
By the way as I mentioned in another thread, Alltrax has a very good document on the precharge resistor and contactor diode, I believe it's titled "Lessons Learned"


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## frodus (Apr 12, 2008)

JRP3 said:


> In a thread on the EVDL I asked about the need to switch the precharge resistor on and off. Alltrax does not show it being switched, just always inline. There were differing opinions, but one person suggested that the life of the caps might actually be extended by having them always powered, "fully formed" was the phrase I believe, and therefore the precharge resistor did not need to be switched. It does draw a small amount of power of course so if the vehicle were sitting for weeks it might drain the batteries. I have not noticed significant drain on my 48 volt setup after a week or so of sitting.
> By the way as I mentioned in another thread, Alltrax has a very good document on the precharge resistor and contactor diode, I believe it's titled "Lessons Learned"


Its fine to keep it "on" all the time. Its how it should be. There shouldn't be any "disconnects" in the path of the precharge resistor. 

Once the caps are charged, there's an ignorable amount of current flowing. Its not discharging at 0.4A (as Tesserect stated) the entire time. Once the caps are charged fully, they do not draw any more current.... and if they do, its leakeage current and its very very small. Your batteries would self discharge faster. Its like a toilet. Once you flush, it refills. Once its done, it stops refulling and doesn't (or shouldn't) take any more water.


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## ZenDaddy (Jul 22, 2008)

JRP3 said:


> In a thread on the EVDL I asked about the need to switch the precharge resistor on and off. Alltrax does not show it being switched, just always inline. There were differing opinions, but one person suggested that the life of the caps might actually be extended by having them always powered, "fully formed" was the phrase I believe, and therefore the precharge resistor did not need to be switched. It does draw a small amount of power of course so if the vehicle were sitting for weeks it might drain the batteries. I have not noticed significant drain on my 48 volt setup after a week or so of sitting.
> By the way as I mentioned in another thread, Alltrax has a very good document on the precharge resistor and contactor diode, I believe it's titled "Lessons Learned"


JRP3,

I just read the "lessons learned" article on Alltax's website. 
http://www.alltraxinc.com/files/Doc120-046-A_TN010-Contactor-Fuse-Diode-Lessons-Learned.pdf
It is an excellent article and they have many more. It gives a good overview of the purpose of the precharge resistor. However, given my limited general knowledge of circuits. I would probably not have realized that I could short the precharge resistor by using a disconnect or switch in series with the contactor with the contactor energized with control voltage. I would have still "followed the recipe" without understanding the process. 

You folks have given me a much better understanding of what I am working with, thank you. 

Michael


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## DIYguy (Sep 18, 2008)

If you look at the Vehicle Integration module from Belktronix, Bryan is using this device to power up his system safely. 

http://www.belktronix.com/vehicleint.html

Regards,
Gary


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## mattW (Sep 14, 2007)

Can someone please summarise this for the wiki? Great info.


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## fugdabug (Jul 14, 2008)

Excuse me,
You have misunderstood this matter.
I am the 'second member'... and you have misstated the situation. I did not 'slam volts' to the contactor or the controller... 
The sequence of start up I have followed and will always follow for my set up is this... I initiate the 12v system (which is wired separately from the ign. switch circuit directly off the battery to power the controller, contactor coil and vacuum system) I then turn the ign. switch key to allow me to steer or turn on headlights, radio etc. - it has nothing to do with the traction or controller etc system!) Then I turn on the 'Panic Switch'. Which is the power from the main traction system. I had used this with my 72VDC system. The reason it 'lurched' is it is started IN GEAR, with the clutch partly engaged... (I hadn't adjusted the clutch pressure properly it is hydraulic) to provide 'load' so the motor doesn't turn free and go 'run-away'. BUT it doesn't go anywhere UNTIL I depress the foot pedal (which is connected by cable to the Potentiometer Throttle).
On the night in question the 14500 controller was under a 144VDC system being rated at 72-144VDC by Kelly, and it fried real crispy for me after about a minute or less of forward movement. 
And please if you want to be an apologist... at least understand what you are talking about. You only serve to confuse the matter with your zeal to protect a product or a personality... This is about building EV's and getting them to run properly.. if you can't deal with that... tough.


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## fugdabug (Jul 14, 2008)

One more note: Kelly programming allows you to set the pre-charge wait time: which is set default to 0.5 sec.. AND the precharge resistor is between the two posts of the TRACTION circuit on the contactor a 300ohm 10W in this case. The Main traction cut-off is along the positive feed from the battery pack to the shunt which goes to the contactor which then splits one off the 'out' post of the contactor to the B+ and another leg to the motor.
(I have a D&D ES31B so the poles are not standard as you can reposition the S1 for clock-wise or counter-clockwise rotation depending on the application of force needed... Honda turns counter-clockwise Toyota turns Clock-wise)
The circuit on the coil is just a 12v power supply in and then out to ground. You have to know that the diode points to the positive side (NOTE: to conduct, diodes are 'forward-biased' that is from the n-type to the p-type end, which is determined by the marked arrow on the diode... in other words the tab 'away' from the contactor poles (or toward the back of the contactor) toward the tab at the 'front' most toward the two pole side...) 
The resistor in not directional in this case it only serves to provide resistance across the poles and has nothing to do with the coil circuit. The contactor is NOTHING more than a large electromagnetic switch that when its coil is excited allows the contacts to come into contact and thus perform the job of connecting the traction circuit... (and there is no fuse following or resistor or whatever, just the controller post at B+.


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## ZenDaddy (Jul 22, 2008)

fugdabug said:


> Excuse me,
> 
> The sequence of start up I have followed and will always follow for my set up is this... I initiate the 12v system (which is wired separately from the ign. switch circuit directly off the battery to power the controller, contactor coil and vacuum system) I then turn the ign. switch key to allow me to steer or turn on headlights, radio etc. - it has nothing to do with the traction or controller etc system!) Then I turn on the 'Panic Switch'. Which is the power from the main traction system.


So if I understand correctly your startup sequence is this:

1. energize contactor directly from accessory battery 
2. unlock steering column and provide voltage for accessories
3. turn on panic button, sending high voltage to controller through closed contactor circuit.

Ok Fugdabug. Its your car.
you really don't see a problem here?

My post has nothing to do with personalities or companies. It has to do with helping folks understand how to protect their controller. Folks who, like me, don't have electrical degrees.

Again, keep your fire extinguisher handy.


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## fugdabug (Jul 14, 2008)

ZenDaddy said:


> So if I understand correctly your startup sequence is this:
> 
> 1. energize contactor directly from accessory battery
> 2. unlock steering column and provide voltage for accessories
> ...


You missed the part about the program within the controller that has a 0.5sec pause BEFORE allowing the energy to pass through... THAT allows a precharge... and NO 'slamming'.


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## Jimdear2 (Oct 12, 2008)

frodus said:


> What we need to put together is a self contained contactor controller with precharge, Diode and a timer. Ignition inputs, safety interlocks, aux input, and a dedicated 12V supply source off the DC-DC converter battery. Totally self contained and designed to protect the controller. Seems that "abnormal" useage is becoming more and more with all of the conversions that are out there.
> 
> It SHOULD be, Ignition on connects precharge to the controller. Once controller voltage is at pack voltage, it checks that the interlocs are engaged and that the car is not in gear, and that the brakes are on, throttle is not pressed...etc. Then it engages contactor and controller is online. If interlock, aux etc becomes disabled, it drops contactor immediately.


Wonderful!!!!

You have posted a spec that sounds valid. You seem to have covered all of the requirements for a standardized start up procedure system they just need to be itemized into a list and a sequence. (I'm new to EV so I may be wrong, others may think of something).

Standardized start up systems/procedures sounds like something we should all have, both for equipment protection and for safety reasons.

There are probably half a dozen EEs and experienced people out there who could draw up a circuit to do this in their sleep. I'm also sure that each one would be different.

Would some of you like to post same and those that post come to a consensus on a design.

It should be something that a simple Klutz like me could build from standardized components.

I'll volunteer time and costs to be the test case to build one. I'm mechanically adept and electronically a klutz. I do have an added resource, my brother is an EE so if I bump my nose I have someone to go cry to. Maybe we should start a new thread similar to the one on wheel motor design. I'm a new to this stuff so senior members, please speak up.

Jim


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## ZenDaddy (Jul 22, 2008)

fugdabug said:


> You missed the part about the program within the controller that has a 0.5sec pause BEFORE allowing the energy to pass through... THAT allows a precharge... and NO 'slamming'.


I didn't miss it Fug,

As I understand it;
If the contactor is closed before the high voltage comes anywhere near it, you have created a direct path around the precharge resistor. It is as if the resistor is not there at all. If the controller can't ever get current through the precharge resistor it really doesn't matter how long kelly's pause is.


Please don't take any of this personally Fug, it is certainly not intended that way.

Michael


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## ZenDaddy (Jul 22, 2008)

Also, again as _I understand it_, that pause is for when an ev utilizes the microswitch in the pot box to energize the contactor every time you put your foot on the pedal, as in many golf cart applications. We usually have our contactors allways on.


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## frodus (Apr 12, 2008)

fugdabug said:


> You missed the part about the program within the controller that has a 0.5sec pause BEFORE allowing the energy to pass through... THAT allows a precharge... and NO 'slamming'.


Are you using the contactor driver that is built into the kelly controller? or are you driving it yourself off the ignition?

http://www.kellycontroller.com/mot/KellyKDHBUserManual.pdf

page 7, connector J1, pins 2 and 5.

Whats funny, is that pages 9-13 don't show J1 pin 2 as being the contactor driver, it uses PWR on the J2 connector.


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## frodus (Apr 12, 2008)

Jimdear2 said:


> Wonderful!!!!
> 
> You have posted a spec that sounds valid. You seem to have covered all of the requirements for a standardized start up procedure system they just need to be itemized into a list and a sequence. (I'm new to EV so I may be wrong, others may think of something).
> 
> ...


I'm already working on something.... but other projects are in front of it. I'll try and move it up a little bit.


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## ZenDaddy (Jul 22, 2008)

Side note!

I fried my controller last friday! I just recieved my replacement from Kelly 5 minutes ago! Not a bad warantee lead time from China eh? They included 3, count em 3, precharge resistors with it! I think they think they are important or something!

Michael


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## rfengineers (Jun 2, 2008)

Jimdear2 said:


> Wonderful!!!!
> 
> You have posted a spec that sounds valid. You seem to have covered all of the requirements for a standardized start up procedure system they just need to be itemized into a list and a sequence. (I'm new to EV so I may be wrong, others may think of something).
> 
> ...


I am in the final testing process for my Step-Start Controller. Here is how it works:

You turn your ignition key to the Start position and release it. This sends a start signal to the step-start (SSC) controller. The SSC turns on the precharge relay which puts a resistor across the main contactor contacts. A timer runs for several seconds (the exact time period has not been finalized yet. After the timer expires the SSC checks the vacuum pump to see if it is still running (it started when you turned on the ignition key). After the vacuum pump stops the SSC turns on the main contactor.

There is a bit more to it--there are two different modes, one where you can turn the main contactor on-and-off with the throttle microswitch (for those of you who think you are driving golf carts) and another mode where the main contactor is turned on with a separate latching relay--this one allows the use of a "panic button" to kill the contactor, but this gives you the general idea.

I hope to have it available in about a week.


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## fugdabug (Jul 14, 2008)

frodus said:


> Are you using the contactor driver that is built into the kelly controller? or are you driving it yourself off the ignition?
> 
> http://www.kellycontroller.com/mot/KellyKDHBUserManual.pdf
> 
> ...


J2 (the second aviation plug... the one most to the right) pos 1 is 12v pos 2 is GND. Pos 3 is '-' pot, pos 5 is 'com wire' from miniswitch on pot. pos 7 is '+' from the pot. PS- there is a picture of the pin positions posted as well or there was, haven't been to the site lately... or try this picture...


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## Jimdear2 (Oct 12, 2008)

Anyone who has been following this thread should take a look at this SD200 or SD300 combination Main Contactor and Emergency disconnect from albright.

http://www.curtisinst.com/index.cfm?fuseaction=cDatasheets.dspListDS&CatID=7&siteID=1

The arrangement of the auxillary allows you to maintain pre charge current even when you have the main contactor open electrically.

For my situation it was made to order.

Jim


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## JRP3 (Mar 7, 2008)

Jimdear2 said:


> The arrangement of the auxillary allows you to maintain pre charge current even when you have the main contactor open electrically.


I'm not sure I understand this. A resistor across the contacts on any contactor will maintain the precharge current, that's the point of the precharge resistor.


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## frodus (Apr 12, 2008)

fugdabug said:


> J2 (the second aviation plug... the one most to the right) pos 1 is 12v pos 2 is GND. Pos 3 is '-' pot, pos 5 is 'com wire' from miniswitch on pot. pos 7 is '+' from the pot. PS- there is a picture of the pin positions posted as well or there was, haven't been to the site lately... or try this picture...


But what do you have the contactor connected to? J2 (12V positive), or the actual contactor control on J1?

If you wired it like their diagram, the precharge should ALWAYS be on, as well as the DC-DC converter. Once you turn the keyswitch on, its going to immediately kick the contactor on. Its totally separate from the controller. The controller doesn't control the contactor NOR the precharge. It is controlled ONLY by the keyswitch/DC-DC converter. Its also safe, because the precharge is never "off".

The J1 connector with the contactor driver on it WOULD control when the contactor goes on after waiting that delay you talked about (.5 second).


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## Jimdear2 (Oct 12, 2008)

Sorry I wasn't clear.

Disregard/
Go back to the site. Call up the spec sheet for the sd200 or sd300. You will see that if you place the prechage resistor across the NC auxillary contacts instead of the man contacts there is a mode where the main contactor can be open and the NC aux contacts are closed. These auxillary contacts remain closed when you close the main contactor contacts.
If you place another precharge resistor accros the NO set of auxillary contacts you can maintain precharge when you use the manual disconnect.
Disregard/

This way the controller ALWAYS has pre charge.

The nice thing is this SD mirrors the load specs of the sw contactor series.

*EDIT*
Whoops !!! Sorry I was looking at it from thre bottom up instead of top down like you were (I.E. Top down, also known as the right way) Talk about feeling stupid.

The point I was really trying to make is thar since this is the main contactor and the mechanical breaker there was no way you could interupt the pre charge.

*END EDIT*

Jim


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## ZenDaddy (Jul 22, 2008)

fugdabug said:


> Excuse me,


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## Tesseract (Sep 27, 2008)

fugdabug said:


> One more note: Kelly programming allows you to set the pre-charge wait time: which is set default to 0.5 sec.. AND the precharge resistor is between the two posts of the TRACTION circuit on the contactor a 300ohm 10W in this case.


Well, there's the problem right there... In my overly long-winded post a page or so back I explained how a certain controller using a 300 ohm precharge resistor, a 120V battery pack and with approx. 3300uF of capacitance inside it would need _5 seconds_ to precharge; if the default precharge time is _0.5 seconds_ then that's just about useless!

Heck, just shortening the precharge from 5 seconds to 4 is enough to cause problems in the above described setup!

I'd either set the precharge time delay to 5 seconds or change the resistor to a 100 ohm 10W cement type (the white rectangular kind). These type have incredible peak to average power capability - almost 100:1 - so they are perfect for this application.


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## frodus (Apr 12, 2008)

Tesseract said:


> Well, there's the problem right there... In my overly long-winded post a page or so back I explained how a certain controller using a 300 ohm precharge resistor, a 120V battery pack and with approx. 3300uF of capacitance inside it would need _5 seconds_ to precharge; if the default precharge time is _0.5 seconds_ then that's just about useless!
> 
> Heck, just shortening the precharge from 5 seconds to 4 is enough to cause problems in the above described setup!
> 
> I'd either set the precharge time delay to 5 seconds or change the resistor to a 100 ohm 10W cement type (the white rectangular kind). These type have incredible peak to average power capability - almost 100:1 - so they are perfect for this application.


Thats IF AND ONLY IF he's using the contactor driver on J1 connector to drive his contactor. Otherwise it goes on when his keyswitch does.


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## ZenDaddy (Jul 22, 2008)

Shouldn't this bit of conversation be taking place in fugdabugs second failure string


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## frodus (Apr 12, 2008)

its directly related to how people are using the precharge resistors.


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## ZenDaddy (Jul 22, 2008)

granted, sorry


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## Guest (Nov 7, 2008)

You are correct but that assumes it is working properly. That delay driver may have been bad and then you'd need to have your system manually set. I always turn on my circuit breaker (panic switch) before activating my contactors because my resistor is in line and will precharge off the main pack. When about 10 to 15 seconds pass I turn on my main contactor. That assures full protection in the event that the Kelly Driver is not working properly. The Kelly delay is not a precharge delay but a check to see if the conroller has the proper amount of power to power the controller. So you really need a manual precharge. It is then possible that you dumped in full pack power to an uncharged controller. 

Mine works smoothly and with out damage to my contact points. I have checked them and they still look new. 

Pete : )



fugdabug said:


> You missed the part about the program within the controller that has a 0.5sec pause BEFORE allowing the energy to pass through... THAT allows a precharge... and NO 'slamming'.


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## Guest (Nov 7, 2008)

Just to clarify my findings. Below is my simple wiring diagram that works perfectly. When I close the circuit breaker main battery power goes to the unopened contactor but allows pack voltage to through the resistor to pre-charge the controller. After I wait my 10 to 15 seconds I then pull my main contactor switch on and open power to my controller. While the main contactor is on and the circuit breaker is closed I will have some power going through the precharge resistor. When I shut down for the evening I close the main contactors and open the circuit breaker all power to the controller is off. Nothing is on. 

Pete : )















gottdi said:


> You are correct but that assumes it is working properly. That delay driver may have been bad and then you'd need to have your system manually set. I always turn on my circuit breaker (panic switch) before activating my contactors because my resistor is in line and will precharge off the main pack. When about 10 to 15 seconds pass I turn on my main contactor. That assures full protection in the event that the Kelly Driver is not working properly. The Kelly delay is not a precharge delay but a check to see if the conroller has the proper amount of power to power the controller. So you really need a manual precharge. It is then possible that you dumped in full pack power to an uncharged controller.
> 
> Mine works smoothly and with out damage to my contact points. I have checked them and they still look new.
> 
> Pete : )


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## Guest (Nov 7, 2008)

Turning on your contactor then opening up your panic switch pounds your controller with high power. You must be sure you pre-charged first. Don't assume. My delay driver that allows the power to the contactor to power up the contactor coil in mine is dead. A real simple static charge can kill that driver in the Kelly and that is what they are trying to fix. 

Did your delay driver work the day you opened power to the controller? Any yes if you left the default at .5 sec. then there was not time for precharge. Like I said it really is not a precharge driver. I was only there to make sure the controller had proper power. My driver is dead so we by passed and made sure our pre-charge was working. It is a pretty simple set up that works flawless. 

: )


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## Hondacrzy (Mar 15, 2008)

So I have a question. Do most people turn their kill switch off at night? I have my charger wired after the kill switch and the car would not charge with it off. Do they shut them off just to make sure the car does not take off in the middle of the night? If the contactor is open all should be good right?


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## Guest (Nov 7, 2008)

I do not know, but I do. I do because if I left that on it would always be powering the resistor and capacitors in the controller. That is a drain and I do not like that. If I knew that I was going to be using it right away I may not turn it off but I usually turn everything off. It's easy to do and does not keep draining your batteries. I do not use my EV daily yet so turning everything off is required to keep the pack voltage up. I mostly just don't like to leave things on. Risky. I do not think my EV will take off in the middle of the night go for a drive on it's own. I can't have main power if I keep both the circuit breaker off and the main contactor coil off. 



Hondacrzy said:


> So I have a question. Do most people turn their kill switch off at night? I have my charger wired after the kill switch and the car would not charge with it off. Do they shut them off just to make sure the car does not take off in the middle of the night? If the contactor is open all should be good right?


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## Hondacrzy (Mar 15, 2008)

I din't really mean "take off" I did not word that very well. I was talking about any short circuit problems


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## Guest (Nov 7, 2008)

You worded it fine but I did not take it like you meant. No problem. I turn it all off to reduce the chance for shorts or other problems. Just being safe. Better to be safe than sorry. 

Pete : )



Hondacrzy said:


> I din't really mean "take off" I did not word that very well. I was talking about any short circuit problems


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## JRP3 (Mar 7, 2008)

Hondacrzy said:


> So I have a question. Do most people turn their kill switch off at night? I have my charger wired after the kill switch and the car would not charge with it off.


That seems like the problem, you should probably wire the charger so you can keep charging with the kill switch off.


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## JRP3 (Mar 7, 2008)

I'm still not sure why people are going through all this precharge delay stuff when there is no reason to turn the precharge resistor on and off


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## rfengineers (Jun 2, 2008)

JRP3 said:


> I'm still not sure why people are going through all this precharge delay stuff when there is no reason to turn the precharge resistor on and off


I would recommend turning off the precharge resistor to remove high-voltage from the controller when the car is not running.

Scenario:
Dude1 "Wow, is this your new electric car?"
Dude2 "Yes, it is!"
Dude1 "Whats it look like under the hood?"
Dude2 "Here take a look." (opens hood.)
Dude1 "Cool, but can't you get electrocuted from those big wires?"
Dude2 "No, the main contactor is off so there's no high voltage up here." (touches motor controller) ZAP!


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## Guest (Nov 7, 2008)

Well now that is an interesting way to look at it. But there is one flaw. Even if I turn off all my power including the power coming in from the pre-charge I will still have the caps in my controller charged. After 3 days of no use my controller caps still hold a deadly amount of charge. So you need to make sure no one touches your stuff because it is a very HIGH VOLTAGE system. A wrong move and you have a crispy critter. Don't let any one paw all over your HIGH VOLTAGE system. Just say you can look. I know some like to look with their hands. 


Just for the record I don't have a specific switch for turning on or off my pre-charge except that I have my circuit breaker in a place that allows no power through when off. NONE 

Having it off is just a safe thing to do. You can choose to be safe or sorry.



rfengineers said:


> I would recommend turning off the precharge resistor to remove high-voltage from the controller when the car is not running.
> 
> Scenario:
> Dude1 "Wow, is this your new electric car?"
> ...


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## ZenDaddy (Jul 22, 2008)

JRP3 said:


> I'm still not sure why people are going through all this precharge delay stuff when there is no reason to turn the precharge resistor on and off


I have to agree with you. My replacement controller is installed. My precharge circuit now bridges everything from Battery+ to ControllerB+. I will remain "fully formed"! (I like that term!). I have created protection from Rfengeneers above scenario with a plastic "cap" that covers all the connections on the faceplate of the controller.

Fugdabugs second controller experience has made me a bit nervous and I have walked away from the truck without turning it on and will go back to it later today and "Walk" all of the connections, relays, fuses, diodes, etc. to try to catch any other issues I might have.

Ill keep you posted.

ZD


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## ZenDaddy (Jul 22, 2008)

Oh, speaking of further issues. When my controller exploded and sent the motor runaway, one of the side affects was that my contactor terminals welded shut. I tapped it lightly with a mallet and they instantly came loose and it bench tested ok, but I am a bit concerned that the "weld" has reduced the surface area on the terminals. Is this a valid concern? If so, what is the risk of reusing it? Should I just replace it?

Thanks


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## Guest (Nov 7, 2008)

To be safe you may be able to purchase replacement contacts and if not then I'd replace them. I know they are expensive but safety is a big concern with EV's and runaway situations. Here is my experience with damaged contacts. We have a well pump on our property and we use a very heavy duty contact switch for when the pump comes on and off. Over the years we had a few failure of these contact switches and every time when the contacts were first damaged but the switches still worked we would clean them up and use them some more and for a short time they worked fine but because of the damage there is no way to make them like new again and they always failed. We now have a set up that will make that problem a thing of the past. So if you have damaged contact points you need to replace the contact points or the contact switch. Don't risk another runaway as they will fail ON. 




ZenDaddy said:


> Oh, speaking of further issues. When my controller exploded and sent the motor runaway, one of the side affects was that my contactor terminals welded shut. I tapped it lightly with a mallet and they instantly came loose and it bench tested ok, but I am a bit concerned that the "weld" has reduced the surface area on the terminals. Is this a valid concern? If so, what is the risk of reusing it? Should I just replace it?
> 
> Thanks


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## rfengineers (Jun 2, 2008)

gottdi said:


> Well now that is an interesting way to look at it. But there is one flaw. Even if I turn off all my power including the power coming in from the pre-charge I will still have the caps in my controller charged. After 3 days of no use my controller caps still hold a deadly amount of charge.


I've designed high-voltage power supplies for radio transmitters, and I've worked with many other design engineers. We always design a discharge path for capacitors that are expected to accumulate a significant charge. In the case we have here, the terminals on the motor controller are known to be exposed to the layman. Any engineer that would design something that would not quickly bleed off those caps is astoundingly incompetent. (I said astoundingly incompetent because it would be rude to call him an idiot)


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## Guest (Nov 7, 2008)

Well then in that case why don't you provide to all of us astoundingly incompetent people who have EV's a competent discharge circuit so we don't kill our selves or anyone else and so we do not come off as incompetent. Oh by the way if we do not know and do not ask how the hell would we know. I know that I have never seen any built in discharge circuit or any that have been added on to make it a safe thing for all those who may be astoundingly incompetent and stick our hand where they do not belong. Looks like we have a pretty large amount of astoundingly incompetent folks around in the EV community?

OUCH!

If you can provide a system that will self discharge for all of us that would be perfect. 




rfengineers said:


> I've designed high-voltage power supplies for radio transmitters, and I've worked with many other design engineers. We always design a discharge path for capacitors that are expected to accumulate a significant charge. In the case we have here, the terminals on the motor controller are known to be exposed to the layman. Any engineer that would design something that would not quickly bleed off those caps is astoundingly incompetent. (I said astoundingly incompetent because it would be rude to call him an idiot)


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## Guest (Nov 7, 2008)

We are not all EE's around here. Guess we should all be then so we don't come across as......................


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## ZenDaddy (Jul 22, 2008)

Another question for the EE's or otherwise educated(I'm glad you guys are here, just remember I'm the proverbial layman and go easy on me)

As I have a fully formed (I just like saying it) controller, what direction does the voltage in the caps want to dissipate after I turn off voltage via the contactor? Will it want to return from where it came from? Through the precharge circuit back to the batteries? Or will it only discharge through a forward path? If I have an always on precharge circuit do I need to protect it somehow? If so, how?

Regards

ZD


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## rfengineers (Jun 2, 2008)

gottdi said:


> Well then in that case why don't you provide to all of us astoundingly incompetent people who have EV's a competent discharge circuit so we don't kill our selves or anyone else and so we do not come off as incompetent.


Excuse me, are you an engineer designing motor controllers for lay consumers? If you are, and you don't consider how the caps in your controller discharge then you are an incompetent engineer!

IF YOU ARE A CONSUMER buying an expensive controller YOU HAVE the right to assume that a COMPETENT person designed the box you are buying.

I am not calling YOU an idiot (unless you are the design engineer) I am calling an engineer who designs something for the general public that puts the consumer at unnecessary risk an idiot.

I apologize if you though otherwise.


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## ZenDaddy (Jul 22, 2008)

rfengineers said:


> Excuse me, are you an engineer designing motor controllers for lay consumers? If you are, and you don't consider how the caps in your controller discharge then you are an incompetent engineer!
> 
> IF YOU ARE A CONSUMER buying an expensive controller YOU HAVE the right to assume that a COMPETENT person designed the box you are buying.
> 
> I am not calling YOU an idiot (unless you are the design engineer) I am calling an engineer who designs something for the general public that puts the consumer at unnecessary risk an idiot.


Man, you EE's really do speak an entirely different language. I'm having a tough time understanding your answer, could you clarify? (lol, just kidding RF)

Smile guys, this is supposed to be fun!


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## rfengineers (Jun 2, 2008)

ZenDaddy said:


> Another question for the EE's or otherwise educated(I'm glad you guys are here, just remember I'm the proverbial layman and go easy on me)
> 
> As I have a fully formed (I just like saying it) controller, what direction does the voltage in the caps want to dissipate after I turn off voltage via the contactor? Will it want to return from where it came from? Through the precharge circuit back to the batteries? Or will it only discharge through a forward path? If I have an always on precharge circuit do I need to protect it somehow? If so, how?
> 
> ...


OK Guys, I am sorry I was misunderstood. I am calling the design engineer incompetent, not YOU!!

What I am saying is the engineer who designed the controller should have taken considerable care in making the controller safe for the intended user. That would include not allowing the bank of capacitors inside the controller to hold a charge for days and days (or even minutes and minutes).

WE, the end users of the controller, have a reasonable expectation that a competent person designed the controller and did not make it unnecessarily dangerous.

So PLEASE understand, I am calling incompetent ENGINEERS idiots, not the EV builder!!!!!

ZenDaddy, in answer to your question, I don't think we need to do anything. I fully expect that the designer of the controller took this important safety feature under consideration. 

In a well designed controller, after you turn off the high voltage the caps should gradually bleed off their charge. Since a connection to the caps is exposed (at the controller terminals) I would expect it to happen in less than one minute.


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## JRP3 (Mar 7, 2008)

The obvious answer no matter how you wire anything is to make sure all your connections are covered from any accidental contact. That's just common sense to me.


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## ZenDaddy (Jul 22, 2008)

Thanks RF.

Hey, don't forget to let me know when your step start sub-assembly is ready. It sounds like a much better setup than I am able to accomplish.

JRP3,

For sure bro, all connections are protected. No access without a screwdriver and I've added loud "danger high voltage" stickers to all boxes and covers. Never know/can't predict when the uninitiated might gain unauthorised access.


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## frodus (Apr 12, 2008)

ZenDaddy said:


> As I have a fully formed (I just like saying it) controller, what direction does the voltage in the caps want to dissipate after I turn off voltage via the contactor? Will it want to return from where it came from? Through the precharge circuit back to the batteries? Or will it only discharge through a forward path? If I have an always on precharge circuit do I need to protect it somehow? If so, how?


Once the voltage of the pack equals the voltage on the caps, the caps will not share any more current. DC-Bus inside the controller in most DC controllers does not get boosted, so the caps will remain essentially at pack level. Meaning, they won't want to "return" to the pack.... they're already at pack voltage. In order to discharge, the load potential has to be lower than the cap potential.

The issue with discharging them:

If you have a precharge resistor charging the caps, and have a discharge resistor discharging the caps, they'll fight and drain your battery pack. Even if there's a switch on the discharge resistor, it'l charge right back up. If you leave the discharge resistor on there, and switch the precharge on and off, it'l apear as a bigger load on your batteries, but only when on.

What you really are saying you want is a little black box that drives a precharge resistor, contactor and a discharge resistor with inputs for a keyswitch, interlocks and aux inputs. When all systems go, key in, precharge, contactor closes. Any interlock or Key off opens contactor and discharges the Controller + and Controller - across the resistor.

As far as the comment about safety, I agree to a point. I work with industrial power equipment (lighting, but used to work automation). The whole thing is, there's no reason anyone but the builder to be under the hood. It should also be well covered and protected from hands and animals getting inside. Its not really that big of an issue for a controller to have 160V on it, if it discharges, its low amps, its just a zap. But again, it should be protected to begin with. There should be NO REASON for someone to get under the hood unless the pack is disconnected via breaker/removal of main fuse/etc. Once this is done, removal of the controller cover. You could have a "discharge" switch under the hood that uses a 100W light bulb to discharge. It doesn't ALWAYS need to be discharged. The only time you NEED it discharged is when you're working on it. We did the same thing on industrial DC drive systems when I worked at GE. We'd turn off the drive, and disconnect the supply and have a huge pole that we'd put across the + and - DC-Bus. it'd spark and discharge all the potential on the Bus instantly.

Its up to the builder to make the vehicle safe and be safe around it. This isn't 9V batteries anymore, Its some high power stuff and we all need to be careful.


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## rfengineers (Jun 2, 2008)

ZenDaddy said:


> Thanks RF.
> Hey, don't forget to let me know when your step start sub-assembly is ready. It sounds like a much better setup than I am able to accomplish.
> ZD


I have it in my hands right now. (look, here it is!! {Waves hands excitedly}) I am making changes to the program code based on comments I have seen here and feedback from some other sources.

I need to head back to the shop to try the changes out on the car, try not to bash me too bad while I am gone.


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## frodus (Apr 12, 2008)

rfengineers said:


> In a well designed controller, after you turn off the high voltage the caps should gradually bleed off their charge. Since a connection to the caps is exposed (at the controller terminals) I would expect it to happen in less than one minute.


In all controllers I've seen, the precharge resistors are always on. The caps would never discharge unless the pack was disconnected.

Point me to a controller that doesn't?


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## Guest (Nov 7, 2008)

I am aware of who you are talking about. I am not an EE and so far I do not see any controllers with built in cap discharge circuits. NONE. I do not under stand why you call a competent EE an incompetent EE if they are not designing a discharge for the controller caps when turned off. I've not seen one yet nor have I heard anyone building one specifically for discharging the controller caps when shut down. I can discharge it manually but that is a pain. I have not seen an automatic or switched discharge circuit. Please help and clarify? Many here are not EE's but are converting on the experience of all the EE's and others who have done so in the past and present and to learn from others mistakes so we do not have to encounter the same trouble. Please help by giving your input and experience so all of us will learn and can build a system that works that is basically faultless. 

Pete

I did not think you were speaking to me personally. 




rfengineers said:


> Excuse me, are you an engineer designing motor controllers for lay consumers? If you are, and you don't consider how the caps in your controller discharge then you are an incompetent engineer!
> 
> IF YOU ARE A CONSUMER buying an expensive controller YOU HAVE the right to assume that a COMPETENT person designed the box you are buying.
> 
> ...


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## ZenDaddy (Jul 22, 2008)

Hey guys,

I want to say that I have learned a great deal from you all in this thread. Even though blowing up my controller was extremely frustrating, my ev is better for the experience.

I really am the layman that follows the recipe and is figuring it all out as I go instead of knowing everything before I started.

I think the info in this thread is excellent and I will agree with Matt and suggest that one of you smart guys sum it all up in terms that a person like me would understand to insert in the wiki.

Thanks again
Michael


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## Guest (Nov 7, 2008)

The pre-charge is always on when the controller is on. In my system the pre-charge is off when I shut down leaving the controller with only power in the caps. The caps can be bleed off. If you always have power and some dolt decides to touch something when they happen to be looking as someones EV they can get a real bad or deadly jolt. It is a safety thing. I like the idea of an auto cap discharge after shut down for safety purposes. 

Pete : )



frodus said:


> In all controllers I've seen, the precharge resistors are always on. The caps would never discharge unless the pack was disconnected.
> 
> Point me to a controller that doesn't?


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## TheSGC (Nov 15, 2007)

You can also think about it as an anti-theft system!

Some idiot attempts to steal your EV, pops the hood to find out why it's not "starting" and gets blown to hell when they move the large wires trying to figure out where the starter inhibitor is. 

Of course we really have to figure out something safe because of those darn inspections that come every year and you know that they will poke and prod things.


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## frodus (Apr 12, 2008)

gottdi said:


> The pre-charge is always on when the controller is on. In my system the pre-charge is off when I shut down leaving the controller with only power in the caps. The caps can be bleed off. If you always have power and some dolt decides to touch something when they happen to be looking as someones EV they can get a real bad or deadly jolt. It is a safety thing. I like the idea of an auto cap discharge after shut down for safety purposes.
> 
> Pete : )


I should clarify. All controllers I've seen, the schematic shows the resistor always on. 

Sounds like your system is pretty safe, manual precharge/contactor engagement right? 

I guess the issue is that most DC controllers are not purpose built to be used in cars/trucks/motorcycles. They're for golf carts and are fairly enclosed. There's no real risk of someone going up to it and getting shocked. With cars/trucks/etc there's more risk, so more needs to be taken into account.

But I agree, all of this feedback and input helps design better controllers/systems. With more and more people converting, it a great idea to have some sort of automated startup/shutdown procedure.


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## Jimdear2 (Oct 12, 2008)

frodus said:


> I should clarify. All controllers I've seen, the schematic shows the resistor always on.
> 
> But I agree, all of this feedback and input helps design better controllers/systems. With more and more people converting, it a great idea to have some sort of automated startup/shutdown procedure.


Please check this and see if I have it right. No more foot in mouth.

I think I've found a way to have constant Pre Charge under normal operating conditions and bleed off the caps during emergency shut down and mecanical disconnect.

I specify a Albright SD200 combination contactor/disconnect with auxillary contacts. (same performance as the SW200).

Look at the attached excerpt from the wiring diagram I'm developing for my pulling tractor. 

Refer to MODE 1.
Subsitute a suitable bleed off resistor for the LED I describe. 

In MODE 1 (emergency and overnight disconnect)
You have phisical and electrical disconnect of high voltage and connection of controller B+ to pack negitive through a bleed off resistor. Place resistor in series (not across) the Auxillary N.C. contacts from the controller B+ to traction Pack negitive.

In Mode 2 (normal running condition Main switch OFF)
You have contactor main contacts electrical disconnect (coil de energized) of the main contacts and pre charge through the auxillary N.O. contacts. Pre Charge Resistor in series with Pack Positive and Controller B+.

In Mode 3 (normal running condition Main switch ON)
You have contactor main contact closed (coil energized) pre charge through the auxillary N.O. contacts is present but unneeded.

I am pretty sure I have figured out a simple way to remotly trip the disconnect for emergencies for those who prefer under hood installation. If somebody is interseted I'll draw it up.

Im waiting to see what others come up with for precharge time delay.


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## rfengineers (Jun 2, 2008)

Trying to clear thing up:

I am NOT saying that we all need to add an aftermarket device to bleed the charge off of the controller resistors.

I am saying that the controller designer should have considered and provided for a discharge path for those capacitors when he built the device.

This would be an important design aspect for any device that may expose a potentially hazardous Voltage under unexpected conditions. (A non-technical person would not know that something inside the black box could shock them even after turning the power off)

The real issue here is precharge, not bleeding off the charge on shut-down.

My position is this: 
1) You really really should precharge your controller before closing the main contactor.

2) IF you do NOT disconnect the HV (e.g. turn off a circuit breaker) when you stop your EV then you should have some method of removing the precharge resistor from the circuit, otherwise the caps will not bleed off their charge. This will result in a hazardous condition existing under the hood when your EV is turned off.

3) IF you DO disconnect the HV when you stop your car, then there is no reason to remove the precharge resistor. BUT, you need to insure that the contactor does not turn on before the HV!!!

On my EV the HV is present at the input to the main contactor at all times. My precharge resistor is inserted in the circuit automatically when I turn my ignition key to "START". The main contactor does not turn on until several seconds later. The precharge resistor is removed from the circuit (by a relay) when the car is turned off.

There are other, equally as valid and safe, methods of designing an EV electrical system, this is just how I did mine. Unfortunately, there are several dangerous ways of designing the system, some of which may result in controller failure or worse. That is what I believe we should be discussing here. My earlier name-calling was meant as humor, I apologize if anyone was offended, but I still maintain that any engineer who is worth a damn will place user safety as one of his major design criteria.


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## frodus (Apr 12, 2008)

rfengineers said:


> Trying to clear thing up:
> 
> I am NOT saying that we all need to add an aftermarket device to bleed the charge off of the controller resistors.
> 
> ...


They can't, because 95% of the Curtis, alltrax and Sevcon controllers were built for markets outside of electric road worthy vehicles. They were built for somewhat continuous (always powered) use. Precharge is Always on to keep the caps charged. Waiting for precharge every time you get in the vehicle would be a PITA for a forklift operator, or someone on the 16th hole in golf. Even if its just a few seconds.

I came from the industrial automation world, and there were many safety measures in place. You couldn't do this without that, and everything had to be dead completely. The big issue is, there's very little regulations for high voltage inside cars at the moment, so they're merely wishlists and not requirements. They'll argue "why the hell were you touching the + and - of the controller to begin with. Most controllers have a disclaimer on the HV parts.

I've got a shock of charged caps when working on a vehicle before, its not that bad. Sure scares you though. Its a short quick burst.


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## Tesseract (Sep 27, 2008)

frodus said:


> The issue with discharging them:
> 
> If you have a precharge resistor charging the caps, and have a discharge resistor discharging the caps, they'll fight and drain your battery pack. Even if there's a switch on the discharge resistor, it'l charge right back up. If you leave the discharge resistor on there, and switch the precharge on and off, it'l apear as a bigger load on your batteries, but only when on.


Excellent point, frodus. That said, this need not be a big problem, practically speaking. Make the discharge resistor (for the "laypeople": a resistor connected across the B+ and B- terminals of the controller - you can add one yourself, btw) equal to 100x the battery pack voltage in ohms and you'll only place a 10mA (1/100th of an amp) drain on the batteries, and still discharge the controller's caps to a safe voltage within a minute or so (anything under 48V is considered "safe"; if you have sweaty skin even 12V may give you a tingle, though).

Finally, if you have a 144V battery pack and put a 15k/2W resistor across the controller's B+ and B- terminals then the equilibrium voltage on the caps with a 300 ohm precharge resistor will be approx. 2.8V (the precharge resistor and the discharge resistor will form a voltage divider and, yes, will continuously drain the battery pack if the main contactor is off but pack voltage is present at it).

I also totally agree with rfengineers' assertion that any capacitor bank capable of storing a significant amount of energy should have a discharge resistor fitted... that's pretty much a basic good engineering guideline. And since energy stored goes up with the square of the voltage, there is a much bigger difference between a 120V battery pack and a 144V one (the caps charged up to 144V will store almost 50% more energy than those charged up to 120V!)


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## ZenDaddy (Jul 22, 2008)

Just a follow up report on my replacement controller.

I have my precharge resistor bridging the contactor and cuttoff switch, it is always supplying controlled pack voltage to the controller. The controller contacts are protected by a plastic cover to prevent accidental contact. I have no bleed off circuit.

I have driven better than 100 stop and go and hilly miles since installing the new Kelly 600 amp, have checked it after every trip, and so far it has only gotten pleasantly warm. I have a 12" x 12" x 3/4" aluminum heat sink with silica gel to dissipate heat and it is doing its job beautifully.

The performance is excellent and I am very happy.

I have recieved good customer service from Kelly (I know that this may not the case for all) and am now glad that I bought the controller from them to begin with.

If any of this changes I will let you all know.

My personal moral of this thread; PRE CHARGE YOUR CONTROLLER!

Happy ev'ing!

ZD


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## elevatorguy (Jul 26, 2007)

ZenDaddy said:


> Just a follow up report on my replacement controller.
> 
> I have my precharge resistor bridging the contactor and cuttoff switch, it is always supplying controlled pack voltage to the controller. The controller contacts are protected by a plastic cover to prevent accidental contact. I have no bleed off circuit.
> 
> ...


Glad you're back on the road and your Kelly is working ok.


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## F16bmathis (Jun 6, 2008)

I wish I would have found this site earlier. In my first S-10, I have blown three kelly KDH4500's, and in my second, I've blown a KDH4500B. 

The first controller in the first truck was my mistake. Because Kelly said the low 12V and the battery pack are isolated, I took it to mean I could short the HV pack to ground! Didn't do it on purpose, but didn't take precautions either, and pow! After consulting Kelly, I thought the case was not supposed to be grounded, so my next two blown controllers were isolated from touching the trucks ground. This also proved deadly! They need to be grounded! I then went to a Curtis and all was well.

The second truck, I installed the KDH4500B, the larger version of thier 500 amp controller and with knowledge from first truck, wired it up. It still blew. Not sure if I turned on main switch first or ignition sw first. They sent me a new one, I went with 36V so the explosion wouldn't be so big, and it worked, so I then went to 144V. It also is good to go, but I'm not getting but MAYBE 200 amps out of it, max of 40MPH. The Curtis 500 got me to 77MPH. So Kelly traded me for a KDH4650B, a 650 amp model. I'll install tonight, and thanks to this site, and Steven from Kelly, will precharge the controller before testing it.

Many thanks to Steven at Kelly controllers for the four FREE controllers he has replaced, and the numerous help with installing.

Brian

www.evalbum.com/1752


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## ZenDaddy (Jul 22, 2008)

Ouch Brian, and I thought it was bad for me!

I really wish that Kelly's owners manuals were more comprehensive. I'm sure they could prevent most returns and customer service issues from diy ev builders if the manual actually told the end user what they needed to know instead of assuming that we are all EE's.

Let us know how it works out!

ZD


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## Voltswagen (Nov 13, 2008)

Hey Zen Daddy
I have the Kelly 12600B without a precharge resistor. After reading all the threads I'm thinking I should install one. Could you suggest a decent one and where in my system it should be installed?
Thanks - Roy


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## ZenDaddy (Jul 22, 2008)

Voltswagen said:


> Hey Zen Daddy
> I have the Kelly 12600B without a precharge resistor. After reading all the threads I'm thinking I should install one. Could you suggest a decent one and where in my system it should be installed?
> Thanks - Roy


Hello Roy

Kelly, unsolicited, supplied me with resistors and diodes with all three controllers I got from them, they were 300 ohm, I don't remember the manufactur or rating. When Im in the shop tommorow I'll check. Are you sure they didn't send you one?

The last controller came with 3 resistors. If you can't find one in the bottom of your shipping box I could drop one in the mail (unless you are in New Zealand, lol) I'm sure that Steven at Kelly would be MORE than happy happy to send you one as well. It would be in his best interest.

Did you recieve a contactor diode? If you don't you should get one! The resistors were packed with the diodes in my box. 

I installed the resistor so that it supplies high voltage to the controller, bridging everything between Pack positive and controller contact B+. It keeps the controller continously at pack voltage. 

so, mine is set up like this on the pos side of the controller-

Battery pos - ammeter shunt - contactor - main fuse - emergency cutoff switch - controller B+

my precharge resistor is on a connector strip with one wire to the shunt and the other to the controller side of the cutoff switch, bridging the contactor and switch.

since I always have juice at the controller contacts I took great care to make sure nobody could accidentaly touch them.

Some guys have a switch cutting off high voltage to the controller that also cuts off the precharge voltage. If you decide to do this take great care not to repeat my mistake (see the first post) and turn that switch on and off while the contactor is supplying high voltage to the controller as this negates the effect of the precharge resistor. 

Some guys have their controller energizing the contactor when they put their foot on the pedal. I don't. If you do ask louder for the correct precharge wiring. In that situation, the diode becomes even more important. Im pretty sure my settup would work for this as well, but I'll let someone with more experience correct me if Im wrong.

There are a number of different ways to set it up, read this thread again for a few good discriptions. I like mine because it is simple and keeps my controller safe.

Ill check back in the am with more info on the resistor.

regards

ZD


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## Voltswagen (Nov 13, 2008)

Thanks ZD for answering so quickly.
No, I didn't get any resistors or diodes with my controller. I don't want to put you to any trouble so I'll call Steve at Kelly tomorrow. He's an aimiable guy and I'm sure he will fix me up. I really want to get this system protected before I put on any more miles. I also wanted to install a "Panic Button" but all the ones I have looked at online are rated only 48v. My system is 120v so I'll keep looking.
Thanks again - Roy


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## ZenDaddy (Jul 22, 2008)

No prob

How many miles have you gone? I drove probably 20 or so miles before the darn thing blew flames and the motor went runaway. Be careful!

Try here for your cutoff

http://www.kta-ev.com/catalog.html


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## Voltswagen (Nov 13, 2008)

Thanks ZD
I checked out that website, they offer a GE Circuit Breaker rated at 120v max. Not sure if I would trip that as at full charge I am over 133v.
I'll ask Steve at Kelly when I call him later today. When I get one I'll install the cutoff and precharge resistor as you suggested.
Oh, and to answer your question: I've driven the car about 70 miles since Creation. The controller barely gets warm. Did I mention it is a KDH12600 'B' ?
Roy


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## Jimdear2 (Oct 12, 2008)

Voltswagen said:


> I also wanted to install a "Panic Button" but all the ones I have looked at online are rated only 48v. My system is 120v so I'll keep looking.
> Thanks again - Roy


 
Look at Curtis/Albright They have the SD series contactor, same specs as the SW series with a PANIC BUTTON built in (a toofer). They also list a series of emergency disconnects

http://www.curtisinst.com/index.cfm?fuseaction=cDatasheets.dspListDS&CatID=7

Some nice looking stuff. I'm going to use a SD200 with mag blow outs and aux contacts. The way I have it set up I'll have pre charge any time the contactor isn't in disconnect mode. I have a nice remote operation set up so the contactor will be located in the High voltage enclosure.

Since you already have a contactor, look at the disconnects. These don't contain a circuit breaker but they are engineered to break max current at max voltage without welding the contacts.

About the remote. A simple pivoted lever that will contact the button and some rope and pulleys with a grab handle.

Hope this helps.


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## F16bmathis (Jun 6, 2008)

I had an S-10 with a Curtis 500 amp. Did 77MPH. I sold it,, and bought a better S-10 and have installed a Kelly 650 AMP controller. Problem is, I'm only getting 45mph. Dont have amp meter yet, so I'm not sure what its putting out, but with the old truck, I had a Kelly 500 AMP and it only reached a maximum of 300 amps initially and quickly went down to a maximum of 170 amps after warmed up. It only did 40 MPH and creeps up hills. 

Why do I get better acceleration/top speed with a Curtis 500 than with a Kelly 650?

I did blow four (4) Kelly's and have learned (eventually) to precharge the controller before applying a full 144V to drive. (turn on main disconnect with pre-charge resistor first, then turn on ignition switch) It'll blow after pedal is applied and throttle switch is made. Luckily all times I had it on jacks!


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## frodus (Apr 12, 2008)

F16bmathis said:


> Why do I get better acceleration/top speed with a Curtis 500 than with a Kelly 650?


because they don't rate their controllers the way the rest of the controllers do. Amp ratings are based on a Temperature rating on the FET's inside, as well as a duration. Sounds like they're running hot, and not for very long... which limits their output current.



> I did blow four (4) Kelly's and have learned (eventually) to precharge the controller before applying a full 144V to drive. (turn on main disconnect with pre-charge resistor first, then turn on ignition switch) It'll blow after pedal is applied and throttle switch is made. Luckily all times I had it on jacks![/


you blew 4? Sounds like Kelly needs to do some redesign. The end user should (within reason) be able to run the controller without a precharge and also an ungrounded case. Things should be isolated enough to keep this from happening. Just sounds like they rushed things.


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## Voltswagen (Nov 13, 2008)

Hey Jimdear2
I looked at the Curtiss SD200 as you suggested......see the spec sheet...max volatge 48vDC
also the SD200B....spec sheet says max volatge....96vDC.
Also looked at SD300 & SD300B.....same specs on max voltage. Still looking for something that can handle more than 120v other than a rope and an Andersen Connector.
Thanks - Roy


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## Jimdear2 (Oct 12, 2008)

Roy,

Yep, your right, sorry, my needs are for 72 volt and 48 volt systems so the Albrights will be fine for me. 

After all, whats good for me must be good for the world.

I got to beleive that there is something out there more sophisticated then a connector and a piece of rope.

Hope you find something nice.

Jim


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## ZenDaddy (Jul 22, 2008)

Volts,

I used the pollack switch from kta. It is not a breaker, it is a switch. It is rated at 300 amps max, however, after the motor went runaway, I took it apart and inspected the contacts for welds and it was perfect. Then I replaced it anyway. If it was going to fail it would have then!!!

Since voltage is the same all the time on both sides of it, sparks don't happen. I also have checked it for any sort of heat many many times and have found none.

just sayin...

I have a choke cable that I took from an old ICE car in the junkyard connected to it that I can pull from the cockpit. Easy and effective.

It is on all the time until something goes bad. If something does go goes bad and I have a major short, the precharge resistor will explode into greasy dust and there will be no juice to the controller or motor after I pull the choke handle.

ZD


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## fugdabug (Jul 14, 2008)

If anyone is interested THIS is my panic switch (and main traction system switch as well...) - presently priced at $(US)333.00 from EVParts (out of Washington State). Good folks. 

"http://www.evparts.com/prod-CB2410.htm"

P.s. To the person who blew 4 Kelly's... what is your total cost for all those doorstops?.. I bet you could buy a new Curtis for the investment a couple times over... I am just curious. I have abandoned the Kelly Controller, and though I have to wait a couple of months due to back-order, have gone with the choice of a Curtis 1231C-8601 (96-144VDC 500AMP). I have calculated the cost in the end will be outweighed by the benefit of quality and a proven track record... 
I am saddened by the lack of innovation in this country, with all that is taking place in our economy and the need for EV tech,.. there should be A HELLUVA LOT MORE garages with inventors and innovators hard at producing new lines of controllers and components... Instead all we have is a 'paint by number' scenario... I am presently scheming out a garage developed component for marketing to the EV community (not a controller unfortunately) but something to spur others into doing the same... simple and easy to produce and necessary.
Come on folks, THINK.


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## F16bmathis (Jun 6, 2008)

Kelly replaced ALL the controllers free of charge. Even sent one, based on a picture I took of the blown one. All of the blown controllers were my fault, confusion over grounding, pre-charge, and now with a 650 amp controller getting 40 mph, when my Curtis did 77mph, I now believe I wired the motor wrong!

Scares me to think I wired F-111's and F-16's avionics systems for 20 years! Of course Air Force manuals were really specific!


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## fugdabug (Jul 14, 2008)

F16bmathis said:


> I now believe I wired the motor wrong!


There isn't much to wire wrong except for ccw or cw... that is it depends on the directions that came with it... four posts right? S1-S2 A1-A2... ? With my D&D ES31B, I loop the A1-S1 and power the A2-S2 for ccw shaft rotation on my Toyota.



F16bmathis said:


> Scares me to think I wired F-111's and F-16's avionics systems for 20 years! Of course Air Force manuals were really specific!


Hmmmm.... like a fellow said to me recently, 'We found that the more products try to accessorize and diversify their options, the more they seem to fail. We have more failures with those kinds of controllers'. 

And I had to agree with him. P.S... If you were in avionics and are familiar with wiring, you have to have some faith in yourself... more than you give yourself credit for... But one question HOW LONG DID YOU GO AT 70mph???  Cause I don't thin' the Kelly go that hard that fast fer very long anyway... THAT is maxxing out the amperage (if you are running to the max of the amps for over one minute and maybe even 30 seconds... with a box like the Kelly... we are talking temperatures that will melt the plastic ends of the box! and inviting the fire gods to make your controller a flaming ball of spit...).


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## F16bmathis (Jun 6, 2008)

Kelly didn't do the 77mph, Curtis 500 amp did. I didn't have the motor wired wrong, just had someones bad diagram. Thought I'd try it though, but controllers don't like the stators shorted and power to the armature!

With the Kelly 650 amp, I'm only getting 41mph downhill as of last night, 20 degrees outside, so heating up of the controller wasn't much of a problem, but wait till summer!

I had a Kelly 500 amp in my last truck, and it never showed more than 300 amps, at startup when cold. After running for a few seconds, and considering I have a huge heat sink and fans for cooling, it went down to less than 90 amps, couldn't maintain 30mph.

I believe Kelly is mis-representing thier controllers. They told me that Curtis is going out of business because Kelly had such great controllers people stopped buying the Curtis. Funny, I'd have to wait a month or more if I ordered a Curtis today. Might just do that anyways, but I am waiting on a Zilla 1K and a Logisystems 1000 amp.


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## F16bmathis (Jun 6, 2008)

Is there any reason why my Kelly KDH4650B 650 amp controller, does worse than a Curtis 1231C 500 amp controller?


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## fugdabug (Jul 14, 2008)

F16bmathis said:


> Is there any reason why my Kelly KDH4650B 650 amp controller, does worse than a Curtis 1231C 500 amp controller?


First off ... my 'neighbor to the southeast'... it is 20 degrees... batteries BE's A BIT COLD!... also, have you checked the programming of the controller, have you set the power equation too low... it is defaulted at somewhere around 85% if I remember right. Did you un-check unnecessary items?... That can be an influence as well... P.S. we are up in 'little Yukon' 38 miles NNW of Grand Rapids MN and 50mi. south of the Canadian border... we had about 1 degree this a.m. its 9:21 now and 11.1 degrees... I am going out to put a heater in the vehicle to toasy up the battery pack whilst awaiting my future controller delivery... Cold schmold... just wait 'til you walk out in your socks and longy's in -60+! cold?... too cold to tell!


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## TheSGC (Nov 15, 2007)

F16bmathis said:


> Is there any reason why my Kelly KDH4650B 650 amp controller, does worse than a Curtis 1231C 500 amp controller?


Did you program it properly? I found that my Kelly KDH09401 really sucked during my first run, but then I went to the programming and found that my Low Voltage was kicking in and slowing the AMPs down to protect the battery, and that my throttle "dead" space thing was not set right and the controller only got to like 60% of total throttle power. After fixing those two things, I did another test run and nearly tore off my motor mount with the extra torque. I haven't gone past 25 MPH yet in my EV for safety reasons, but my initial tests showed that I had plenty of power left, I just needed some higher speed roads.


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## fugdabug (Jul 14, 2008)

F16bmathis said:


> Kelly didn't do the 77mph, Curtis 500 amp did. I didn't have the motor wired wrong, just had someones bad diagram. Thought I'd try it though, but controllers don't like the stators shorted and power to the armature!
> 
> With the Kelly 650 amp, I'm only getting 41mph downhill as of last night, 20 degrees outside, so heating up of the controller wasn't much of a problem, but wait till summer!
> 
> ...


CURTIS is NOT going out of business, they are busier than a five-tailed cat in a rockin' chair factory!!! 
The problem is YES, Kelly mis-represents their products... I think that can be fairly well documented by quite a few disgruntled customers that have posted on this site (myself included). 
I do know that my order for the 1231C-8601 is due in a month or so... They (Curtis) have been rather overrun in the past year and especially the past few months due to a major increase in demand. The Russco charger I ordered from 'EVPARTS.com' is back-ordered, the PakTrakr remotes are back-ordered, the heavy duty battery terminals are back-ordered... UH, ya think maybe folks are out there doing the same thing we are??? in droves???


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## F16bmathis (Jun 6, 2008)

I set the amps to max, after starting slow due to my numerous controller explosions. The throttle is set to 5-0V, throttle works. Pot is set at 20% to 80%. I do have full travel of the Pot. Battery voltage is set at 120 for a low, and 160 as a high. Maybe set the voltage low, lower? I've seen it go to 90V under heavy accel with the Curtis on my last truck....


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## TheSGC (Nov 15, 2007)

F16bmathis said:


> I set the amps to max, after starting slow due to my numerous controller explosions. The throttle is set to 5-0V, throttle works. Pot is set at 20% to 80%. I do have full travel of the Pot. Battery voltage is set at 120 for a low, and 160 as a high. Maybe set the voltage low, lower? I've seen it go to 90V under heavy accel with the Curtis on my last truck....


The Kelly starts current limiting at 110% of your setting, so what would be 132 volts. I set my pot to 10% to 90%. What voltage are you running that gets you to sag to 90 volts? If it's the 144 volts that is says in the garage, then you are killing your batteries with that kind of sag! 

Also a question on your throttle- I assume you have a Curtis PB5/PB6 throttle- did you add a third wire to it or make some modification? 

I changed the wiring on my PB5 to a three wire setup to match the Kelly diagram exactly. If you have a diagram of your throttle setup/wiring I can test I theory I have.


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## Voltswagen (Nov 13, 2008)

Hey Guys
After reading all the threads regarding Kelly Controllers it would appear that I have been attending church in my Birthday Suit!
I've put about 70 tough miles on my 120v Bug *without* a precharge resistor and the Kelly 12600B didn't notice yet.
So last night I stopped by Radio Shack and picked up a pair of resistors.
I'm enclosing a picture of them here *hoping *that someone will say "Yeah use one of those." or "What have you been smoking?"
These are 100ohm 10 watt resistors. From what I have read here and info from Kelly, one of these resistors should be installed as a bridge between
the two large poles on my Contactor. Please take alook at my pic, I used the 1.75 liter bottle for reference.


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## TheSGC (Nov 15, 2007)

Voltswagen said:


> Hey Guys
> After reading all the threads regarding Kelly Controllers it would appear that I have been attending church in my Birthday Suit!
> I've put about 70 tough miles on my 120v Bug *without* a precharge resistor and the Kelly 12600B didn't notice yet.
> So last night I stopped by Radio Shack and picked up a pair of resistors.
> ...


Those resitors should be fine. My Kelly came with a 300 ohm resistor and it is working fine. 100 ohms would limit the inrush current to 1.2 amps, which is more than the 300 ohm would, but it should still be perfectly fine.


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## F16bmathis (Jun 6, 2008)

I added the 1K resistor and modified the Pot like the Kelly diagram that has all three versions shows with the wiper shorted to one side... doing this from memory, and the 1K and other side going to 5V and throttle on controller.

The 90V was under load at 65+ mph using a Curtis in the old truck. Probably was killing the batteries. I heard 120V under load for a 144V system is considered done.

I'll post a diagram in the pictures section...


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## F16bmathis (Jun 6, 2008)

Diagram is at http://www.diyelectriccar.com/garage/cars/103

I don't have the amp meter or volt meter installed yet, and my dc/dc is fried (must have over volted when trying to charge the batteries)


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## TheSGC (Nov 15, 2007)

F16bmathis said:


> Diagram is at http://www.diyelectriccar.com/garage/cars/103
> 
> I don't have the amp meter or volt meter installed yet, and my dc/dc is fried (must have over volted when trying to charge the batteries)


I'll do a test when I get home this afternoon, but I don't think your throttle will go the full 0-5 volts with that setup, which would explain the reason why you can't go past 41 MPH. I had a similar setup with a homemade controller trying to use the Curtis pot without adding the third wire, and the maximum output was 50%.


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## Voltswagen (Nov 13, 2008)

Thanks for the response SGC. I'll install a resistor this weekend.
Also do I need a Diode anywhere on my system? I have none.
Roy


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## F16bmathis (Jun 6, 2008)

I did have 0v to 5v out of that setup... I can recheck it again. I'll install my voltmeter tonight so I can monitor pack voltage.

By the way,

Thanks for all the help!


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## TheSGC (Nov 15, 2007)

F16bmathis said:


> I did have 0v to 5v out of that setup... I can recheck it again. I'll install my voltmeter tonight so I can monitor pack voltage.
> 
> By the way,
> 
> Thanks for all the help!


Ok, so is your controller setup for 0-5 volts or 5-0 volts? With the way that Curtis is wired, I am going to assume 5-0 volts and I just did a test a found something very interesting. 

Assuming your throttle is 5-0 volts, that would mean that off at 5 volts and full throttle at 0 volts, you are getting only 80% of total throttle power from the PB6. Since the total resistance of the system is 6K ohms, the PB6 is 5K and the resistor is 1K, that would leave you with 6k at off (5 volts) and 1K at full throttle (1 volt).

I don't know if your throttle cable works with the entire range of the PB6 (mine doesn't gotta fix that-) but even if it does, you are only getting 80% total possible power. It might be even less if your cable doesn't pull the throttle to maximum.

It really doesn't matter if it's 5-0 or 0-5 volts, that setup will only work to 80% tops, which is a possible cause for the low speed.


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## F16bmathis (Jun 6, 2008)

It is a 5-0V setup, I had 20% to 80%, just went to 20%-100 % throttle. Also I have the torque set to torque. It has Torque, balanced and speed. Should I go with speed? whats the difference?




TheSGC said:


> Ok, so is your controller setup for 0-5 volts or 5-0 volts? With the way that Curtis is wired, I am going to assume 5-0 volts and I just did a test a found something very interesting.
> 
> Assuming your throttle is 5-0 volts, that would mean that off at 5 volts and full throttle at 0 volts, you are getting only 80% of total throttle power from the PB6. Since the total resistance of the system is 6K ohms, the PB6 is 5K and the resistor is 1K, that would leave you with 6k at off (5 volts) and 1K at full throttle (1 volt).
> 
> ...


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## F16bmathis (Jun 6, 2008)

Also, I checked the throttle V again, had 5V at no pedal, and it quickly went to 0V well before half throttle...?

Maybe another version of Kelly's 3 different pot wiring designs is in order?


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## TheSGC (Nov 15, 2007)

F16bmathis said:


> Also, I checked the throttle V again, had 5V at no pedal, and it quickly went to 0V well before half throttle...?
> 
> Maybe another version of Kelly's 3 different pot wiring designs is in order?



Now that is very interesting. The setup really calls for having the three wires on the POT and nothing else. If you have to add a resistor to the setup, then something will not be right. The original wiring diagram that came with my controller only had the three wire setup, and nothing to do with the added resistor or shorting the wiper to anything else.


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## TheSGC (Nov 15, 2007)

F16bmathis said:


> It is a 5-0V setup, I had 20% to 80%, just went to 20%-100 % throttle. Also I have the torque set to torque. It has Torque, balanced and speed. Should I go with speed? whats the difference?



I have no idea what the difference between the settings are. I have mine set to torque, but when my EV is done I might try the different settings to see what they do.


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## F16bmathis (Jun 6, 2008)

TheSGC said:


> Now that is very interesting. The setup really calls for having the three wires on the POT and nothing else. If you have to add a resistor to the setup, then something will not be right. The original wiring diagram that came with my controller only had the three wire setup, and nothing to do with the added resistor or shorting the wiper to anything else.


Well, I have an attachment to an e-mail Steven sent me, shows the 3 wire pot with a 1K ohm to ground? and 5v? (doing the memory thing again) and it continues on to the motor thermistor and 1K which I do not have connected. 

But also, I have a Kelly manual, which shows all three versions of connecting the pot, showing them ALL CONNECTED, which is a little confusing whether you need the 1K for all versions.

I'll see if I can take a picture and add a link to it...


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## TheSGC (Nov 15, 2007)

F16bmathis said:


> Well, I have an attachment to an e-mail Steven sent me, shows the 3 wire pot with a 1K ohm to ground? and 5v? (doing the memory thing again) and it continues on to the motor thermistor and 1K which I do not have connected.
> 
> But also, I have a Kelly manual, which shows all three versions of connecting the pot, showing them ALL CONNECTED, which is a little confusing whether you need the 1K for all versions.
> 
> I'll see if I can take a picture and add a link to it...


I didn't bother with the thermistor and just hooked up the throttle. I still think that throttle setup with the shorted wiper and 1k resistor is holding you back. I know that in my case my throttle is physically be held back by 15% or more because my cable does not have enough throw to use the whole PB5.


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## F16bmathis (Jun 6, 2008)

I have uploaded the wiring diagram Steven from Kelly sent me. Its here http://www.diyelectriccar.com/garage/cars/103

Its the way I have mine wired, except I didn't connect the thermistor.


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## fugdabug (Jul 14, 2008)

fugdabug said:


> CURTIS is NOT going out of business, they are busier than a five-tailed cat in a rockin' chair factory!!!
> The problem is YES, Kelly mis-represents their products... I think that can be fairly well documented by quite a few disgruntled customers that have posted on this site (myself included).
> I do know that my order for the 1231C-8601 is due in a month or so... They (Curtis) have been rather overrun in the past year and especially the past few months due to a major increase in demand. The Russco charger I ordered from 'EVPARTS.com' is back-ordered, the PakTrakr remotes are back-ordered, the heavy duty battery terminals are back-ordered... UH, ya think maybe folks are out there doing the same thing we are??? in droves???


Well cancelled my order from EVUSA for the Curtis 'cause I found one in stock and cheaper at KTA... I just got it in the UPS drop today!... MY GOD IS THAT SUCKER HUGE!!!... the 1231C-8601. I will take some photos for comparison side by side with the Kelly 14500B... The Curtis is a honker!!! I will have to reconfigure the whole shootin' match... but gotta say it comes with a GOOD warranty, and I don't think I will have to worry about that! good luck ya'll with your Kellys...


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## evcars (Mar 15, 2008)

fugdabug said:


> Well cancelled my order from EVUSA for the Curtis 'cause I found one in stock and cheaper at KTA... I just got it in the UPS drop today!... MY GOD IS THAT SUCKER HUGE!!!... the 1231C-8601. I will take some photos for comparison side by side with the Kelly 14500B... The Curtis is a honker!!! I will have to reconfigure the whole shootin' match... but gotta say it comes with a GOOD warranty, and I don't think I will have to worry about that! good luck ya'll with your Kellys...


Good choice.  You will be much happier!! I unfortunately know from experiance.


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## fugdabug (Jul 14, 2008)

xtreme cartz said:


> Good choice.  You will be much happier!! I unfortunately know from experiance.


I was hoping I could see the photos up close like... but they don't expand! By the way did you put up a garage entry? YOU SHOULD... looks intriguing!!! And well thought out!


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## fugdabug (Jul 14, 2008)

A bit of a P.S. to you all:
I really did mean 'Good luck' to those of you with working Kelly controllers... the key word here is 'WORKING' controller... Any one with a working controller is fortunate... at least you can still have the joy of making your vehicle go down the road!!!... I have to start my rebuild... and it is 6 degrees this morning... before I can have that joy again, Curtis or not... ya gotta do the deed, first! So be warm, be happy... and keep thinkin' EVs.


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## TheSGC (Nov 15, 2007)

fugdabug said:


> A bit of a P.S. to you all:
> I really did mean 'Good luck' to those of you with working Kelly controllers... the key word here is 'WORKING' controller... Any one with a working controller is fortunate... at least you can still have the joy of making your vehicle go down the road!!!... I have to start my rebuild... and it is 6 degrees this morning... before I can have that joy again, Curtis or not... ya gotta do the deed, first! So be warm, be happy... and keep thinkin' EVs.


I am going through the registration paper work now before I go for another drive. I have put about 10 miles on my Kelly and have had no problems, but it seems controllers these days from any manufacturer are hit or miss. 6 degress? I usually have to wait until its above freezing because the hood latch gets frozen shut!


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## causalitist (Feb 6, 2009)

i build my own controllers ... not yet a guru by any means .. but i know what im doing. 

let me get this straight... charging the main input capacitors too fast can cause the rest of the controller to fail? i have no idea why.. it would be hard on the caps but the rest of the circuit should care less. 

obviously im wrong. *could someone please explain why a massive pulse of amps into the main caps destroys stuff .. other than the caps?
*
is there a massive voltage spike because of wire induct and di/dt?






Wouldnt be hard to use a little "capacitor charger" IC from Linear.. or a opamp and a mosfet.


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## rfengineers (Jun 2, 2008)

causalitist said:


> i build my own controllers ... not yet a guru by any means .. but i know what im doing.
> 
> let me get this straight... charging the main input capacitors too fast can cause the rest of the controller to fail? i have no idea why.. it would be hard on the caps but the rest of the circuit should care less.
> 
> ...


As far as I know, the only problem caused by large inrush currents is welding of relay contacts on the main contactor.


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## major (Apr 4, 2008)

causalitist said:


> it would be hard on the caps but the rest of the circuit should care less.
> 
> *could someone please explain why a massive pulse of amps into the main caps destroys stuff .. other than the caps?*


Hi causal,

Not sure if the inrush harms other components, but as you point out, it is detrimental to the caps themselves. So, as those caps degrade and ultimately fail, it stresses the other components. Maybe that is what people see as the failure mode, getting cause and effect confused.

By far the main reason to use a precharge is to get the arc off the main contactor.



> Wouldnt be hard to use a little "capacitor charger" IC from Linear.. or a opamp and a mosfet.


A resistor has always worked for me.

Regards,

major


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## fugdabug (Jul 14, 2008)

hello,
Concerning the Kelly Controllers, in the time since the failures and my subsequent change of design to a Curtis 1231C-8601, I have done a bit of research... For instance in my scenario now with 108VDC a Curtis controller, a main contactor with the inclusion of a reversing contactor,.. The Curtis takes a '25W' pre-charge resistor... I am going to use a 25 watt 120VAC light bulb in a mount within the compartment to act as a 'pre-charge resistor'... the reason for this is to 'warm-up' the controller. 'Slamming' or putting the full charge to a controller, shortens the lifetime of the controller and can lead to catastrophic failures... in almost ANY controller.
(and SCREW Kelly!)


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## JRP3 (Mar 7, 2008)

Why not just use an actual resistor? They are smaller and probably more robust than a light bulb filament.


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## fugdabug (Jul 14, 2008)

The nice thing about the capacitor use as opposed to a mosfet or IC is that it reduces 'another thing to worry about', it is simple to apply. And I like simple... kinda like my brain... .
When I found a reference to the use of the 25W bulb as a 'pre-charge resistor', it was a 'knock knock puddin' head!' moment for me. I just built the box for my 'bulb resistor' yesterday!... who'd-a THUNK it?? now that is thinking out of the box~
P.S.(disclaimer) If anyone was offended by my remark on Kelly, just consider this... it wasn't your money or time or self that was offended by the 'company'... it was mine and me. And it was in my nature to let others know what happened, because it could save others the time and money and suffering! So it is JMHO of the product its quality and the company. -respectfully 'fugdabug'


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## fugdabug (Jul 14, 2008)

was a matter of finding... I did find one (in a lot of 100)... and it was in England. Found a couple of college stores that offered for students... it was just too much of a hassle ordering waiting... the two reasons i am behind already by what 5 months??? is waiting on suppliers and weather - the parts waiting was frustrating (a few of which got returned due to being damaged or wrong in the first place or both!) the other I cannot control,.. SO rather than feeding the negativity that has accumulated due to all that. HEY! think simple use what you have at hand and that can be replaced rather 'immediately' and if it isn't 'cool' enough or doesn't fit the norm... at least I am smiling, it works for me - and that is what counts. wait til ya see the heatsink I came up with (will post in another thread)


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## engineer_Bill (Jun 24, 2008)

frodus said:


> Its fine to keep it "on" all the time. Its how it should be. There shouldn't be any "disconnects" in the path of the precharge resistor.
> 
> Once the caps are charged, there's an ignorable amount of current flowing. Its not discharging at 0.4A (as Tesserect stated) the entire time. Once the caps are charged fully, they do not draw any more current.... and if they do, its leakeage current and its very very small. Your batteries would self discharge faster. Its like a toilet. Once you flush, it refills. Once its done, it stops refulling and doesn't (or shouldn't) take any more water.


Atually there are good reasons you need to switch off the precharge resistor. 1. As pointed out, the precharge reisitor is often underrated for the pack voltage/current. If the capacitors should short the full pack voltage AND current wil be across the little precharge resistor continuously and possibly burning it out, note overheated resistors can fail shorted causing a full short through the resistor and the controller, BAD. Better; have an indepedant disconnect to fully remove power when not in use. 2. Safety. A 120 OHM precharge resistor will pass 1 amp at 120volts, It only takes .1 to .2 amps to KILL YOU. A secondary disconnect along with a manual disconnect may save your life.


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## fugdabug (Jul 14, 2008)

engineer_Bill said:


> Atually there are good reasons you need to switch off the precharge resistor. 1. As pointed out, the precharge reisitor is often underrated for the pack voltage/current. If the capacitors should short the full pack voltage AND current wil be across the little precharge resistor continuously and possibly burning it out, note overheated resistors can fail shorted causing a full short through the resistor and the controller, BAD. Better; have an indepedant disconnect to fully remove power when not in use. 2. Safety. A 120 OHM precharge resistor will pass 1 amp at 120volts, It only takes .1 to .2 amps to KILL YOU. A secondary disconnect along with a manual disconnect may save your life.


EngineerBill,
Thank you for noting that!!! I just in a blink of 'reason' had thought to myself that once the charge had been made (resulting in a dimming of the bulb...) it might be nice to 'switch' the resistor (in this case my lightbulb...) OFF, as the amperage at full would possibly fry the 'resistor' wiring! Makes perfect sense to me to do the same with a standard pre-charge resistor as well. electrical fires that 'burn down the world' have a tendency to make one more weighted toward safety...


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## JRP3 (Mar 7, 2008)

engineer_Bill said:


> Atually there are good reasons you need to switch off the precharge resistor. 1. As pointed out, the precharge reisitor is often underrated for the pack voltage/current. If the capacitors should short the full pack voltage AND current wil be across the little precharge resistor continuously and possibly burning it out, note overheated resistors can fail shorted causing a full short through the resistor and the controller, BAD.


A small fuse inline with the resistor should stop that.


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## fugdabug (Jul 14, 2008)

ya know... the Kelly that I was sold and the one that was sent to replace it BOTH used a 300Ohm 10W(!) resistor... I wonder if switching that would have made any difference?.


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## F16bmathis (Jun 6, 2008)

I have my manual disconnect installed so its inside the cab on the floor next to the shifter. Once I'm done driving, its the first thing turned off right after the ignition key. This way, it keeps any voltage from going to the main disconnect with the pre-charge resistor across it.

Also, my Kelly shorted out (had it isolated from the trucks ground- don't do that) and the pre-charge resistor took all the voltage to the controller, got red hot! It wasn't anywhere it would've started a fire, but it wasn't pretty either.

I also dis-like Kelly, if not for the blowing of four of them, then due to thier ratings being way off. A Kelly 1000 amp never even put out 400 amps, but a Curtis pulled the full 500, and my Zilla pulls the full 1000 on the same setup.

I would'nt use a light bulb only because if the filament breaks, you no longer have a pre-charge resistor. Unless you use two?

As I understand it, not using a pre-charge resistor causes the capacitors to charge instantly, causing them to expand, and short out. As soon as full power is applied, they blow, causing fire and smoke, and in the event of four Kelly's (I had issues) causes smoke fire and spits sparks out the controller, and cranks the motor to over max speedometer reading on a Chevy S10.

For those who want to know what Kelly issues I had keep reading...

1. Shorted B- to trucks ground. Didn't think it was an issue till it happened cause the book says they are isolated.
2. Isolated the controller from the trucks ground, (tech rep said to) used rubber so the controller did not touch the trucks ground. Bad, it needs to...
3. Still had the controller un-grounded to the trucks ground, made it to the gas station. (I was buying soda)
4.Grounded the controller to the trucks ground. (same tech rep said to) Worked a little till I listened to someone who said to put the tranny in third and forget about it. It didn't like that. Use all the gears!

My two cents.

Anyone have any cheap LiFePO4's? Is there such a thing? Driving year round would be nice.


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## JRP3 (Mar 7, 2008)

F16bmathis said:


> Anyone have any cheap LiFePO4's? Is there such a thing? Driving year round would be nice.


Check out James and Dave's bulk buy thread. $1.10 Ah for TS and SE cells.


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## engineer_Bill (Jun 24, 2008)

JRP3 said:


> A small fuse inline with the resistor should stop that.


True, but if the fuse blows you will have no precharge resister anymore, do you have a way to detect this? Also we are back to if you use a 1 amp fuse you can merrily fry while the fuse happily conducts the 0.1amps it takes to stop your heart. A second contactor removes that risk, and gives you a backup disconnect if the primary contactor welds shut.


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## rfengineers (Jun 2, 2008)

engineer_Bill said:


> True, but if the fuse blows you will have no precharge resister anymore, do you have a way to detect this? Also we are back to if you use a 1 amp fuse you can merrily fry while the fuse happily conducts the 0.1amps it takes to stop your heart. A second contactor removes that risk, and gives you a backup disconnect if the primary contactor welds shut.


Place your voltmeter on the controller side of the contactor. When you turn on the precharge you will see the voltage ramp up and then finally jump to the pack voltage when the contactor closes.


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## causalitist (Feb 6, 2009)

wont a precharge resistor greatly reduce the effectiveness of the capacitors during actual operation? we want a completely empty capacitor to charge using just a few amps... but then during operation, we want these caps to suck up and put out as many ripple amps as exist... thats why we spend 4x the money on 18 milliOhm capacitors. 

so dont we need to have a little circuit that senses cap voltage; and once it is around 80% of battery voltage -it closes the contactor and removes the precharge resistor from the circuit?

actually, this would also work as a low battery cut off... just by coincidence .. and also by coincidence: 80% is about the cutoff volts for anyone using lithium polymers like me!  ........ not to mention "at the main cap" would be the ideal place to sample battery voltage because of its stability there during operation...

seems to me this is the "right" solution, and would be a very simple circuit.. I threw one together on spice using a transistor, few .25 watt resistors, and a 22n cap as the "sensor" .. which tells a 15mOhm mosfet to throw the contactor., and another to bypass the precharge resistor ... and when battery voltage is below 80% (~3v/cell for lipos) it opens the contactor. worked well even with a bunch of noise. would be a 1 square inch size circuit too.


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## Anaerin (Feb 4, 2009)

causalitist said:


> wont a precharge resistor greatly reduce the effectiveness of the capacitors during actual operation? we want a completely empty capacitor to charge using just a few amps... but then during operation, we want these caps to suck up and put out as many ripple amps as exist... thats why we spend 4x the money on 18 milliOhm capacitors.


The way I understand it, precharge resistors are connected in parallel to the "ignition" contactor (But not the "Main" contactor). So when there's power to the system, a small current "leaks" by the contactor to keep the capacitors charged, but that current is nowhere near enough to actually run the motor.

Something like this (Excuse ASCII diagram):

```
Precharge
                                    Resistor
                               ,----/\/\/\/\---,
                              /                 \
Battery =--------||----------+--------||---------+--------= Controller
                Main                Ignition 
              Contactor             Contactor
```
That way, when you're working on the car, you throw the main contactor, which will kill the whole system. But for most of the time, the main contactor is closed. The ignition contactor is the one switched by the key.

Another alternative I've heard of is having the precharge circuit engaged by turning the key to the "Start" position, and having the ignition contactor on a delay (Or pre-requisite on the precharge circuit being closed already). This way starting the EV is more natural (It won't go anywhere until you turn the key to "start", but once that's been done once, you don't need to do it again). This also gives the advantage that the controller and circuitry aren't at voltage all the time.


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## causalitist (Feb 6, 2009)

rfengineers said:


> As far as I know, the only problem caused by large inrush currents is welding of relay contacts on the main contactor.


ya, ive instantaneously charged giant 500v caps when i was 12 years old. .. heck, thats all i did.. and then short them on whatever metal was closest to me. they dont blow up or start on fire.. it might degrade life.. but i just dont see it causing controller failure unless this has been done over a thousand times. certainly not something that would cause acute failure. .. unless by some other means, like what i first mentioned: insane dv/dt of charging cap causing voltage spikes in the wires(inductors) that surpass the capability of the caps in question.. but i have a feeling this is not the case, that dv/dt pulled by cap = dv/dt cap can "handle" .. handle meaning reduce Vspike of. just cuz integral of derivviive or whatever.


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## causalitist (Feb 6, 2009)

Anaerin said:


> ```
> Precharge
> Resistor
> ,----/\/\/\/\---,
> ...


Ohh! thanks alot! i was going to have a mosfet be the ignition contactor, but thats not as safe. makes sense. im only concerned with the wasted power from two coils as opposed to one.. all the high DC voltage contact/coil contactors i see draw some decent watts. 
i need around 150v and 50amps DC .. wouldnt mind higher amp rating, but that is all i need right now.

its for a 21 speed mountain bike running on 148v of lithium polymers at 50Amps, perm magnet dc motor, 600amp 1200v IGBT module, 10khz PWM, mc33035 chip, acs755-200 allegro hall effect current sensor(really neat chips! check em out!), a 10,000uf 250v 18 milliohm cap, and two 30uf 
8 milliohm metal film caps. 

total overkill.. but i made this controller so i can take it off the 10hp bike and slap it in a small car if i wanted. all the wires are busbar.

hey! am i allowed to parallel diodes to get a higher current rating?? i have a feeling there are some rules for this i forgot.. i want to parallel a few rurg8060 .. 80amp, <75ns .. anything bigger is too slow for my liking.


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## jumpjack (Sep 9, 2012)

ZenDaddy said:


> Recently 2 forum members who had spent a great deal of time money and energy building ev's experienced Kelly controller failures.


Sorry for digging up such an old thread, but I'm going to replace my controller with a Kelly controller and I didn't exactly understand what you mean, mainly due to specific english/electric jargon, being me Italian... 

Where could I find tips and explanations about what a contactor is and what its use on an EV, and why we need a precharge resistor, and where to place it?


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## onegreenev (May 18, 2012)

What do you have and what Kelly are you considering buying? You might consider something else but if you have a golf cart of Zenn Truck or something you might do just fine with a Kelly. 

We need details and your correct. This should not be tacked onto such an old thread. You should start a new one. It will be fine to ask the administrator to move it to a new thread for you. 

But in the mean time we need details of what you have and whats wrong with what you have. 

Pete


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## F16bmathis (Jun 6, 2008)

jumpjack said:


> Sorry for digging up such an old thread, but I'm going to replace my controller with a Kelly controller and I didn't exactly understand what you mean, mainly due to specific english/electric jargon, being me Italian...
> 
> Where could I find tips and explanations about what a contactor is and what its use on an EV, and why we need a precharge resistor, and where to place it?


Search GOOGLE. Ask questions here and at evalbum.

A contactor connects the power from the battery to the controller's big switch basically. It is placed between the battery and controller, usually close to the controller on the positive side of the battery pack.
A pre-charge resistor is placed across the (big main) contacts of the contactor. The resistor lets the controllers capacitors charge up slowly instead of instantly. Our controller capacitors charged instantly will blow out soon if not right away.

Some controllers have pre-charge resistors built in. Netgain is one such beast. Look up Curtis 1231C manual on google and look through it. It has lots of info and diagrams to get you going.


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## jumpjack (Sep 9, 2012)

Thanks for replies.
I'll also open a dedicated thread about my 1500W/60V e-scooter. ;-)


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## jumpjack (Sep 9, 2012)

fugdabug said:


> One more note: Kelly programming allows you to set the pre-charge wait time: which is set default to 0.5 sec.. AND the precharge resistor is between the two posts of the TRACTION circuit on the contactor a 300ohm 10W in this case.


Sorry for digging up this old thread, but this is the only one In found about this topic.
So there are Kelly controllers which include a precharge resistor? Which ones?
I received my 72810 controller with an external big resistor, with no explanations about what to do with it.
The manual shows a pre-charge resistor, but it appears continuously connected, which is weird.
Anyway I also purchased an active precharge resistor:
http://www.nothnagel-marine.de/prod...aktor-Spannung--120V-max--Systemspannung.html

How am I supposed to connect it to my system?


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## F16bmathis (Jun 6, 2008)

jumpjack said:


> Sorry for digging up this old thread, but this is the only one In found about this topic.
> So there are Kelly controllers which include a precharge resistor? Which ones?
> I received my 72810 controller with an external big resistor, with no explanations about what to do with it.
> The manual shows a pre-charge resistor, but it appears continuously connected, which is weird.
> ...


This was a while ago! The precharge resistor goes across the main contactor. Its function is to slowly charge the capacitors in the controller over a milli second or so. If they were instantly given the pack voltage, the capacitors may charge too fast and expand or explode. Well, maybe not explode, but its bad for them. picture here...

```
http://www.thunderstruck-ev.com/images/thumbnails/0/800/800/Curtis_1231_Wiring_Diagram.jpg
```


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## dougingraham (Jul 26, 2011)

F16bmathis said:


> This was a while ago! The precharge resistor goes across the main contactor. Its function is to slowly charge the capacitors in the controller over a milli second or so. If they were instantly given the pack voltage, the capacitors may charge too fast and expand or explode. Well, maybe not explode, but its bad for them. picture here...
> 
> ```
> http://www.thunderstruck-ev.com/images/thumbnails/0/800/800/Curtis_1231_Wiring_Diagram.jpg
> ```


The precharge is also there to prevent the contactor from welding its contacts closed. Without precharge the contactor might close only once and never open again. Without precharge the instantaneous inrush current is going to be limited only by the quality of the batteries and interconnects. On typical EV batteries this would be in the several thousand amp range.


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## RIPPERTON (Jan 26, 2010)

F16bmathis said:


> This was a while ago! The precharge resistor goes across the main contactor. Its function is to slowly charge the capacitors in the controller over a milli second or so.


A millisecond isn't slow.
Proper precharging takes about 10 seconds to get the caps to within 10v of the battery voltage then its ok to close contacts.
In a non racing vehicle is normal to leave the precharge resistor across the contacts all the time. Makes the system easier to work on too when removing and refitting battery packs.


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## jonescg (Nov 3, 2010)

Yeah precharge is something you need to get right - a common source of headache for many DIY conversions. Stuck contactors, fires, dodgy contacts...

The precharge circuit is effectively a resistor in parallel with the terminals of the main contactor. However the resistor must have a suitably rated switch or relay in series with it, and engaged some seconds before the main contactor. 

A resistor permanently across the contactor is fine, however it means there is always a high voltage available to the inverter, even when the system is "turned off".

Some folks use a time delay like a 555 timer, while several makes of inverter are smart enough to have a separate precharge relay output and a main contactor output. The voltage across the DC bus capacitor is monitored, and when it appears to have stabilised, the main contactor is able to close.


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## jumpjack (Sep 9, 2012)

jonescg said:


> several makes of inverter are smart enough to have a separate precharge relay output and a main contactor output.


I think this is how the device I purcahsed work: it has 6 terminals; I think 2 for key switch, 2 for precharge resistor activation and 2 for main contactor activation.


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