# KELLY controller KDH14501 Post mortem 2



## biscayne (May 15, 2009)

Hi guys, my first posting after a Kelly experience. (I had hoped on a good outcome, but..)

I carefully choose the KDH14501 for my 96V system. 144V (180V max), 250A continuous, 500A max. 
I had 2 of them. Each one diseased smoking after about 30 miles. 

After the first one blew, Steven Li was so kind to sell me an other one for about 500$.
He asked me to dispose of the bad controller, not to tell about it, and promised to send me a new one, 4 inches longer and also stronger. (why would some one ask for such a thing?)
When I looked through the manual, and saw that not only the dimensions had stayed the same but also they had reduced the ampere rating down from 250 to 200A, Steven Li confirmed, that “the case* is *longer”, and the 200A was due to a “different Testing procedure” but really the new ones are stronger.
After having read Tesseract`s analyses of a KDH12600, I know that Kelly had realized people actually expected to see anything close to what’s published on the label, and *readjusted* the performance data labels.
“Different testing procedure”? ?
I told Steven my doubts, and he finally sent me another KDH14501 for a reduced price, my 2nd controller. I was a little bit astonished, since I had left the choice open for Steve to pick any controller he found suitable, I had told him that I had no need for regen. Actually no one knew why the KDH`s fets had blown, but the new controller was supposed to be a completely new designed series, much stronger and even had an optocoupller!
Well, it neither had different dimensions, nor was it any different to the old one: Same place, old procedure, after 30miles engine out, controller smoke, I was going downhill this time- couldn`t have overloaded. 
I`ll continue this post, so that’s why I`ll go into details later.
Now it was time for me to get to know *Kelly`s praised customer service.* 
*If you pay, you can buy something-*
Steven found the reason for the failure right away trough a distant diagnosis. I had told him, that a dcdc converter, supplying the fieldwindings with about 3A at 70V, was connected in parallel to the controller. Here`s what he wrote: *“The dcdc loaded the prechargresistor. So the prechargeresistor won`t be able to charge the controllers internal capacitors….”*
Up to this point I wasn`t sure where to place Steven Li. A mix of used car salesman and electronic engineer? I read through some of his statements on the internet, also the statement where he outed himself as an engineer. Now I know, those technical statements didn`come from him. It took him some time to respond too. Well it didn`t take him much time to come up with this beauty- “The dcdc loaded the prechargresistor” 

After having gone through installing and deinstalling and a thorough analyses, I can say: Kelly controllers will die for 2 reasons *if* properly installed, of course with a prechargeresistor. 
*1. Transient voltage*, which is the case when using them on 96V or higher. Transients build up to hundreds if not thousands of volts in the form of spikes, that last only may be for 10^-9 s. Kelly uses completely unprotected Fets rated at 200V. Again, I`ll write details later.
There is no way to adjust for a shutdown if the voltage reaches 136V transients!!! 
And here goes the whole VB Kelly program, its for playing. 
*2. Overcurrent* is the logic consequent failure cause for a Mosfet assembly with a gate circuit layout that`s built under the premises that “electricity travels fast”. It sure does, and the first FET gets all the current- every time its turned on- and that’s pretty often.
The Kelly labels represent the components max values added up, not real tests, those the paying customer does - or they change the testprocedure- until the desired outcome takes place- see above.
Others have found out, unfortunately I read teseracts analyses just too lat.
In my case it sure wasn’t over current, since Kelly had obviously down rated the current to under 50A. One can easily imagine that my car didn’t drive very fast, with the second controller with only a max of 60V on the engine. But I didn’t mind, hoping that it would at least last longer than the first one. Wrong- 30miles- smoke- out.

Anyway, I lost money. I went through a lot of install- and reinstall. I even got to drive, and I gained wisdom: Sometimes saving can be expensive. And I found truth: Don’t trust Chinese labels. 144V 400A!!! They smile at you, and it`ll cost you- 
*After over 2000$ spent,* I not only bought 2 controllers, but also other gear- some didn’t break *yet,* *I have no controller.*
I had sent the 2nd KDH145xx to Kelly for repair. Steven Li had earlier pointed out, that in addition to being stronger and longer, the new KDH would have optocoupling, meaning the units would be repairable in the future. 
*Kelly stuff is not repairable: *When a Fet, that lacks preventive circuitry is operated beyond its limits repeatedly, it explodes and flames can be the result. (That’s why in some applications protective circuitry is necessary). Fets fail open in all directions! Meaning a single failure would lead HV to the gate and other Fets. A optocoupler can prevent HV to go to the uC section, but that’s the only thing left- maybe. 
Now *the brown sauce*, that Tesseract described, starts to *make sense:*

*First* it helps to hold everything in place, especially the fets, that are fixed to the board with tiny plastic screws.
*Second*, who wants to freely exhibit such simple unprotected circuitry? (Is that why Steven asked me to not show, and to dispose the first KDHB?)
*And third*, Kelly`s electronic is completely irreparable! One single failure- and everything goes! So why not put brown sauce on such a masterpiece? 
*Fourth: Why repare?* When Kelly sell for a reduced price- looking inside the kelly- I saw what tesseract meant- The parts for the 14501 are worth maybe 100$ that is in the US, or EU! Excluding the metal case, which they`ll use over again. So every unit sold for a reduced price means profit. *Why should they build repairable units?*

Of course *Steven Li allowed me to buy an other controller-* for a reduced price. And he pointed out, that the KDHx14xxx is again stronger. And he put emphasis on checking the prechargeresistor, and he wrote, that other products also breake if not handled just right.
Bottom line, I`m to stupied to do it right, everybody has to learn… he wrote.
I have a degree from a European university in electronic engineering, with scope on power electronics. When I read Kellys manuals, I thought “looks good”
Now I remember: There was a company that had bought old Intel processors, overpainted the components markings and sold them world wide as new chips.
Got to be careful trusting labels - especially when something is sold cheap!


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## Jozzer (Mar 29, 2009)

So did you test to see if the precharge resistor was passing enough current to precharge the caps despite the DC-DC convertor being there? 

It seems you must be doing something wrong to blow 2 controllers the same way so quicly.

I've got 6 Kelly's (some of them 144v and run at 144v nominal and 175v max) in service myself and with customers and have not had a single failure in over a year..

Also, why use 144v on a 96v system? Overrating the voltage on a controller leaves you with FET's that can pass less current..


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## TheSGC (Nov 15, 2007)

Ok, why do you have a DC/DC supplying field windings? This implies a Shunt/SEPEX motor, not a series.

And as for "Unprotected MOSFETS", that is not true. Many people have overlooked something, these Kelly controllers are not a Half Bridge setup. They use Synchronous Rectification, hence no freewheeling diodes. The second bank of fets are the diodes. 

However, not knowing the exact MOSFETs part number, I am led to believe that your motor setup is more like a Shunt/SEPEX than series, and that probably cause excess load on the FETS because SEPEX's act like generators, and probably overloaded the FETs while going down hill.

I do have a Kelly (KDH09401), and I am not being a fanboy or anything, but I just want to understand why controllers have been failing. So far I have found all the failures to be "misuse" of product. Also, the KDH14xxxx have had the most problems I think.


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## biscayne (May 15, 2009)

The eingine is a brushed Brown bovery ratet at 15KW continous. Old piece. It`s dataplate showes it has a fieldwinding that needs to be supplied with 70V 2,5A. The dcdc is reducing the 96V down to this voltage.
The prechargres is supplying both with the batteryvolatge at all times, there`s nothing wrong with this. 
Interesting fact is, that the Fet of the dcdc, a IRFBA9020D, 200V 50A is just fine. 
I`m aware of the bridge setup of the 14501 it needs that for the regen, there´s nothing wrong with this only- no snubber, TVS, There`s no real Voltage or currentprotection- in softwere??? I saw that.

According to Steven inductivity doesn`t matter to their controller. 
The statement about a "loaded precharge res. tells me that I shouldn`t continue, that surely wouldn`t bring me further.
If I would have picked one 200A, 120V, no, no, 400A 144V it reads....
Ican understand you guys faith- I was hoting for a good outcome myself..
Going through the net, one sure can find many reports about failing Kellys.
By the way, I`m still waiting for a receipt for the product bought from Kelly, all I have is a creditcard statement. 
And to all that have one working,- much luck-


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## Watt-a-mezz (May 20, 2009)

[quote SCG

I do have a Kelly (KDH09401), and I am not being a fanboy or anything, but I just want to understand why controllers have been failing. So far I have found all the failures to be "misuse" of product. Also, the KDH14xxxx have had the most problems I think.[/quote]

May I ask how to avoid the"magic smoke" I have read about with the Kelly controller. I have the KDH 9500 to use with adc 9" and the PB6 potbox with the third wire added. The 300k precharge resistor was included,along with small diodes for the contactor. Any help would be greatly apreciated. Take care Watt.


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## peggus (Feb 18, 2008)

If I would hesitate a guess at the failure cause I would say the low inductance of your sepex motors armature in conjunction with kellys crappy engineering contributed to your failures. 

Steven may claim that inductance doesn't matter but that is only an indicator of his lacking understanding of how the controllers work.


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## fugdabug (Jul 14, 2008)

biscayne said:


> Hi guys, my first posting after a Kelly experience. (I had hoped on a good outcome, but..)
> 
> After the first one blew, Steven Li was so kind to sell me an other one for about 500$.
> He asked me to dispose of the bad controller, not to tell about it, and promised to send me a new one, 4 inches longer and also stronger. (why would some one ask for such a thing?)
> ...


Yes, I know 'mr. Li', and I know how he operates... "why" you ask... it is simple:
You are NOT guaranteed a UL rated controller. There is no one really checking the QA of the product. That is the problem. I have had vehement supporters that tried to tell me I was wrong and I did this wrong and that wrong, mainly because they thought my complaint was just being a complainer or trying to bring 'disrepute upon KELLY'... NO, I was PO'd... and maybe I was a newbie, but the product is not reliable. The replacement I got was a flat out DUD. I went through two of them. 14500's... rated 72-144VDC. The first one (which is recorded in prior threads) went up in a ball of smoke and flame. I am on my third iteration of the experiment and the third controller is a Curtis 1231C... I figure they ask 1400 for a kelly... I buy a Curtis for 1500 and am guaranteed quality right off. (I originally thought Kelly referred to Kelly Industrial Electronics... not mr. 'Steven' Wen Li.)
P.S. By the way, take it from someone with the tire-tracks across the back... FORGET all those that try for the sake of argument to dissuade you, IF THEY DON"T OWN THE PRODUCT or if they aren't building then I don't care how much schooling or what kind of degree they hold... They don't know what they are talking about because theory is ONE THING, experience is another,.. Also just remember: It is YOUR MONEY! no one else's.
just some thoughts. - fugdabug owner of 'whitebird' (in the 'garage')


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## biscayne (May 15, 2009)

Fugdabug, I see yourè a beliefer, you probably made a similar experience like I did.
You know, at first I thought I was dealing with a company in the US, Kelly tarnishes good.
Did you ever figure out what really killed your KDH`s? Current or voltage?
Does your Curtis work fine now?
I didn`t even notice exactly the moment when my first one blew, I noticed the main breaker tripped while the car was on the charger. Just before I had driven up a steep hill. 
Looking inside the KDH1401B revealed: molten source pins, exploded Fets.
At first I asumed overcurrent. 
But the second broke while I was merely coasting downhill, using very overall power. It couldn`t have been overcuent. And it sure wasn`t a "loaded prechargeres".
Overvoltage seems to me much more the reason, the Fets inside are IRFB4227 200V devices. With no protection, except for the freewheeling current, I mean no sort of snubber, 200 V are reached fast. 
Here I have a question to anyone that would know: I asked Steven Li more than once, but only got the following reply: "I don`t think that an other company would answer all your questions".
Here`s the question: Can overvoltage, (transients) that eventually lead to exploding mosfets burn (melt down) a source pin? Or is a molten source pin always a sign for too much current?
By the way, any other company would only be asked such a question if something similar happened to their product.


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## Harold in CR (Sep 8, 2008)

I know NOTHING about Electronics. That being clear, I built a portable sawmill. I put a ¾ HP 12VDC electric motor on the sawhead feed system, so it ran the sawhead down the length of the log. 

NOW, I bought a PWM off ebay, and promptly burned up the fets. Contacted the seller, and, he sent another. Burned up THAT one. Contacted the seller. He provided a third with a heavy duty copper circuit board, which was driven by the PWM. It worked for 2 minutes, then burned up traces on that board. 

I contacted folks on a forum related to sawmilling, and 1 guy, in Wisconsin checked with his engineering staff at work. They decided I had "voltage spikes" coming from the motor, back into the PWM, because of the pulsing of the motor ???. There is no other circuit board hooked to this PWM, other than the one with the "goodies' and fets.

He sent me some devices (capacitors)?? that look like a piece of Chiclets chewing gum, with 2 bare wires sticking out. I put 1 across 1 leg of the power connection on the motor, and put the wire under a bolt on the motor mount. Did the same to the other power lead. Problem solved. ??? Whadda I know. It works for 7 years, same setup. 
I would bet that the same principal applies with cars and controllers. That might be why the downhill coasting burned up the controller. Motor generating some form of voltage-current ???


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## Qer (May 7, 2008)

biscayne said:


> Here`s the question: Can overvoltage, (transients) that eventually lead to exploding mosfets burn (melt down) a source pin? Or is a molten source pin always a sign for too much current?


If a source pin melts it's because of too much current. It acts like a fuse, when the current starts to rush the pin heats up until it breaks. Now, the reason for the over current can, however, be because of spikes or over voltage. If the MOSFET gets a too high voltage over itself, the transistor structure will be damaged and the MOSFET will be short circuited so the current flows freely until the pin (or something else) breaks.

This is true for all kinds of transistors and not limited to MOSFET's only, we've blown a few IGBT's in our prototypes while testing the limits... 



Harold in CR said:


> He sent me some devices (capacitors)?? that look like a piece of Chiclets chewing gum, with 2 bare wires sticking out. I put 1 across 1 leg of the power connection on the motor, and put the wire under a bolt on the motor mount. Did the same to the other power lead. Problem solved. ??? Whadda I know. It works for 7 years, same setup.


I'll risk being ridiculed by Tesseract for weeks by saying that that sounds like snubbers to me. 

Apparently it's some kind of transient killer at least. They can be made in different ways depending on the situation, but the main purpose is always to short circuit the transient before it rises enough to damage the delicate silicon-based components. All silicon (transistors, diodes, processors etc) are sensitive to transients and even a big 1kA transistor can be killed even by static electricity! That's one of those things that really can be a bitch when you're constructing electronics, especially since it might not destroy a component but only damage it slightly so it suddenly breaks without a reason one day.


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## fugdabug (Jul 14, 2008)

biscayne said:


> Fugdabug, I see yourè a beliefer, you probably made a similar experience like I did.
> You know, at first I thought I was dealing with a company in the US, Kelly tarnishes good.
> Did you ever figure out what really killed your KDH`s? Current or voltage?
> Does your Curtis work fine now?
> I didn`t even notice exactly the moment when my first one blew, I noticed the main breaker tripped while the car was on the charger. Just before I had driven up a steep hill.


Well,.. mine was just a 'no-go' on the second one. 14500B... the lights were on but nobody was home... and the way it is constructed doesn't allow for good inspection, it is 'tarred' over with a coating on all the parts. I even found particles, 
As for your breaker tripping... Do you have a charger interlock (a special relay that cuts power to everything but the battery pack so the charger is the only current in and out of the pack(s)??? Because it sounds like you didn't. AND driving up a steep hill... (with the charger on ?) it confused me. Driving up a steep hill shouldn't have anything to do with the matter unless you were really goosing it, and your amp gauge should have told you you were in a 'danger of over amperage' zone... did you notice any over-amping there? I am not an expert by any means, I am still on a learning curve as well...


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## mamodbasher (Apr 22, 2009)

Speaking of cheap controllers, I followed one of the links on this website to a place called "Buggies" and they seem to have Curtis controllers, or looking a lot like Curtis controllers for what looks like very reasonable prices. I was looking at one unit rated for 60 to 72 volts at 720 amps for $549. There were others in there as well - most 36 or 48 volt units at 300 or 400 amps, but at less than $400. These seem to be quite inexpensive compared to any I've seen elsewhere - am I missing something? I am looking for a controller for 72 volts (and I have no intention of increasing that number) at around 400 amps and this seemed like a good deal - please set me straight if I am misled here  Ken.


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## Jimdear2 (Oct 12, 2008)

mamodbasher said:


> Speaking of cheap controllers, I followed one of the links on this website to a place called "Buggies" and they seem to have Curtis controllers, or looking a lot like Curtis controllers for what looks like very reasonable prices. I was looking at one unit rated for 60 to 72 volts at 720 amps for $549. There were others in there as well - most 36 or 48 volt units at 300 or 400 amps, but at less than $400. These seem to be quite inexpensive compared to any I've seen elsewhere - am I missing something? I am looking for a controller for 72 volts (and I have no intention of increasing that number) at around 400 amps and this seemed like a good deal - please set me straight if I am misled here  Ken.


Ken,

Check out the Alltrax line of controllers. The 7245 (24 to 72 volt nominal 450 amps). These controllers have a lot of nice features including a very intuitive computer set up of a lot of parameters and it has data logging as well. Their web site has good custome support as well. I learned a lot from reading through their documents.

It also has a high pedal disable function (prevents those lurches when you turn on the key and have your foot on tthe go pedal and a half speed reverse function.

Shop and you can find them new for under 500.00 and used for over 200.00

I like mine as you may notice I bought a new one and a used one for my tractors.


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## mamodbasher (Apr 22, 2009)

Jimdear2 said:


> Ken,
> 
> Check out the Alltrax line of controllers. The 7245 (24 to 72 volt nominal 450 amps). These controllers have a lot of nice features including a very intuitive computer set up of a lot of parameters and it has data logging as well. Their web site has good custome support as well. I learned a lot from reading through their documents.
> 
> ...


Sounds like a plan - thanks!


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## mamodbasher (Apr 22, 2009)

Hi Jim - I checked into the Alltrax today through D&D Motors in Syracuse. He said he would have no problem selling me a 7245 and thought it would work well with the 9 inch motor - but, he also said that he would not offer the usual warranty with it, as he thought that the application might be stretching the current limits of this unit. So, having said that, would you still recommend this controller? Has anyone had a problem with Alltrax units frying? It seems to me that if you are doing tractor pulling with these, they must be more rugged than that. If they can be programmed to a lower max current (say 300 amps), then that should prevent any damage - yes? I just don't want to have a unit fry and find out that my warranty is void  Ken.


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## Jimdear2 (Oct 12, 2008)

mamodbasher said:


> Hi Jim - I checked into the Alltrax today through D&D Motors in Syracuse. He said he would have no problem selling me a 7245 and thought it would work well with the 9 inch motor - but, he also said that he would not offer the usual warranty with it, as he thought that the application might be stretching the current limits of this unit. So, having said that, would you still recommend this controller? Has anyone had a problem with Alltrax units frying? It seems to me that if you are doing tractor pulling with these, they must be more rugged than that. If they can be programmed to a lower max current (say 300 amps), then that should prevent any damage - yes? I just don't want to have a unit fry and find out that my warranty is void  Ken.


Ken

You don't hear much about Alltrax. I think that is a good thing. I believe that means they don't break down much. Check the number of posts out there when Kelly and Logisys were having trouble.

The only thing I've seen about Alltrax on this site in the last year is people wishing they made bigger controllers. (Ive heard rumors that some people have modded these controllers and pushed 1000 amps)

Go to the Alltrax website and download their softwear (its free) start it up and look through the paremeters that can be adjusted. I know some other controlllers have more bells and whistles but do you really need more? The data logging finctions (both realtime and saved to a downloadable file) alone are priceless to me since I am starting something new. The maximum current limit is just one of many adjustments. 

I bought my motor and controller from D&D because I was impressed with their attitude and responses to my questions. I told them what I wanted to do and they came up with an answer and price that was fair.

You need to make your decisions based on what you want to do. Call Alltrax themselves and ask questions, they are a helpfull bunch.

I'm VERY comfortable with my choice.


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## mamodbasher (Apr 22, 2009)

I bought my motor and controller from D&D because I was impressed with their attitude and responses to my questions. I told them what I wanted to do and they came up with an answer and price that was fair.

You need to make your decisions based on what you want to do. Call Alltrax themselves and ask questions, they are a helpfull bunch.

I'm VERY comfortable with my choice.[/quote]

Sounds like you are satisfied with the purchase, so based on that, I will take the plunge. For the record, I did call them and I was also impressed with their attitude, other than the warranty thing - which I also understand. I'm goin' in - wish me luck!


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