# Tips for Slow Acceleration



## Bowser330 (Jun 15, 2008)

omonoid said:


> SO i finished my build last summmer, then went to college and didn't really get a chance to use it until this summer. It is a Vw 86 GTI, 120v using optima yellow tops and an 8" motor, clutchless. It works fine, but my biggest issue is acceleration. I pretty much drive flooring the pedal the whole time. I think my potbox is a PB-5, i can double check.
> 
> Is it normal to drive usually flooring it? can i change the pot for better preformance, or am i stuck?
> 
> ...


Well as long as your three main components are checked and are okay (Motor, controller, batteries) 

Check if your potbox at WOT is giving you 100% of your 500A from your controller. Maybe something got messed up and WOT is only 50%, then you are talking about only half of your torque, 42ftlbs of torque.

I would also start out in first gear and see what happens since you may need more torque multiplication, 500A in a 8"ADC (im assuming you have a 203-06) is only 85ftlbs and 58hp.
http://www.evparts.com/cms/picts/products/mt2116peakmotoroutput.PDF


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## omonoid (Aug 30, 2009)

What does WOT stand for? Full accel i assume? What would be the best way to check that there is 500A? Just a ammeter on both terminals of the pot?

I havnt done much to actually check the controllor, batteries and motor, i just assumed they were working fine since the car runs. What's the standard method of confirming these are all ok?



Thanks


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## Ziggythewiz (May 16, 2010)

I drove floored all the time my first year. In 2nd I top out at 45 anyway so with a typical speed limit of 40 I'd just keep it floored, traffic allowing.

You should be able to tell if you're using your full potential by the amount of current you're pulling. Does your ammeter peak near the full capacity of your controller? What controller do you have?


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## Bowser330 (Jun 15, 2008)

WOT = wide open throttle, yes, full acceleration, pedal to the floor.

I would invest in a ammeter like Ziggy says, so you can monitor the peak Amps you are getting from your controller and into your motor. 

Full acceleration with 85ftlbs in 1st gear should not be slow...

I used to have a 1997 civic (~2600lbs) with ~89ftlbs from the ICE and it wasn't so slow I was worried about getting through an intersection quick enough. And it didnt even have the full torque from 0rpm!

Per his Evalbum he has the P&S DIY 144V 500A controller...


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## omonoid (Aug 30, 2009)

Yeah i have the P&S DIY 144V 500A controller, which i assembled myself, but i think it is working the way it should. So your saying at WOT my in dash ammeter should read 500A? it rarely passes 250 when flooring it up a hill, ive never seen it as high as 500. Plus my breaker is rated for 300A i think, so that would flip at 500A anyway. Maybe my controller is having issues?

Any advice?


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## PStechPaul (May 1, 2012)

Most 300A circuit breakers will hold 500A for a few seconds, so that should not be a problem. You might want to check all your connections and wiring to see if you are dropping too much voltage there, and monitor the battery voltage for sag. You can check the voltage (or resistance) on the accelerator pot box to see if it it is pushing the controller to maximum.


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## Ziggythewiz (May 16, 2010)

With a 500A controller you should be hitting at least 450A unless the pot isn't giving a full signal or the controller is throttled back. Disconnect the pot leads from the controller and check what values you get when *someone else* presses pedal to full and at 0.

Just how sluggish are you? If you're at a stop, how fast are you by the time you get across the intersection? My bug's never been sluggy on the low end (unless I'm in 3rd or 4th gear) even if I limit it to 200A.


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## mora (Nov 11, 2009)

You might need to adjust your controller parameters for snappier acceleration and proper throttle range. Have you connected your controller to a computer? Download a program called RTD explorer.

ps. I have VW 89 Golf/rabbit with P&S controller too. Works just fine.


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## omonoid (Aug 30, 2009)

PStechPaul:


> You might want to check all your connections and wiring to see if you are dropping too much voltage there, and monitor the battery voltage for sag


How would I test for voltage sag? All I’ve done so far is confirm that the voltage across the pack is the same voltage across the controller when the car is on.



> You can check the voltage (or resistance) on the accelerator pot box to see if it is pushing the controller to maximum


.

I tested the resistance of the potbox with my ohm meter and at 0 acceleration, it read 0 ohms and a full, it was 1. That seemed odd to me. Shouldn't it be the opposite? 0 resistance at full throttle.

Ziggythewiz:


> Disconnect the pot leads from the controller and check what values you get when *someone else* presses pedal to full and at 0.


How would I go about doing this? If I disconnected the motor the controller would have no load right? But if I left the motor connected, and did that, the car would move, making it very hard to measure anything 
And by values I assume you mean amperage to see how close to 500A it gets. 

I have my ammeter/shunt wired on the negative side between the pack and the controller (and a fuse). Would that work for measuring the amps the controller outputs, or would I need to measure the amps between the controller and motor?



> Just how sluggish are you?


If I’m stopped on a slight uphill before an intersection it probably takes me 10 sec or so to finally get across and up to speed. That's a rough estimate, but I’m defiantly starting to think something is wrong based on everyone's responses.

mora:


> You might need to adjust your controller parameter


I was aware I could do that, but haven't. Do you think it is necessary? I remember back when I was building the controller I didn’t have the adapter to hook the controller to my pc. Did you get some usb adapter or something?

Also it is kind of a hassle to take my controller out and disassemble it enough to hook to my pc since I glued plexy glass to the sides. I can still take it out, but only if you really think it is necessary. 
I’ll probably try all the other suggestions first.

Thanks to all for helping me resolve this


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## Ziggythewiz (May 16, 2010)

When testing the pot box the car (and controller) should be off. You need to disconnect the pot leads (two little connectors going into the controller), not the motor. Hook the leads to a DVM that can read ohms, you just want to see what resistance signals you're sending to the controller. A PB-5 should read ~0 at 0 and ~5000 at full. 

If the pot reads good you'd need to check the controller. Did you mention which you have? A curtis has an adjustment screw, for example, and others do it in the software.

As for performance, do you not have any flat roads? It's hard to relate to "slight uphill" as A) closest I have is an overpass, and B) "slight uphill" means something different to everyone. I think typical for crossing a flat intersection after a stop would be 2-3 seconds, and 20-30 mph on exit.


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## omonoid (Aug 30, 2009)

My potbox seems fine. it went from 0 to 4830.

My controller is a P&S DIY 144V 500A, which can be connected to a computer, but i havent tried to yet.

My biggest question is what is the best way to see if the controller is outputting 500A like it should? How would i check it before hooking it up to a computer?

As for the performance at intersections, it is defiantly more sluggish than "2-3 seconds, and 20-30 mph on exit." Ill take a stopwatch on my next drive and get a good estimate.


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## alvin (Jul 26, 2008)

Hi omonoid

I'm with moro, you should set the controller using RTD. You may be pressing accelerator without doing anything till your almost out of cable travel.

You could adjust the linkage so it starts right before you get a high pedal fault and the led is blinking. That would give you more travel on your cable while it is doing something.

Alvin


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## Ziggythewiz (May 16, 2010)

You need an ammeter to see what you're pulling. Didn't you say already that you weren't seeing high nubers with it?

I would think you could hook a laptop to the P&S w/o removing it from the car, but don't have one so not sure.


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## omonoid (Aug 30, 2009)

alvin:
I have the cable on the second from bottom hole on the lever arm. It seems like it is perfect since when the accel pedal is not being pushed the lever as just touching the left end. When the accel is floored the arm is just touching the right end. If i tightened the cable anymore, the resting (0 throttle) position of the arm would not be all the way left.


Ziggythewiz:
I just went for a drive and payed close attention to my gauge I dont think it ever went higher than 400, but it was in the 300s in 1st gear. In second gear it takes like 10-15 sec to accel past 200 amps and even longer to get to 300+. In first it is faster getting to maybe 400A in 10 sec or flooring.

I enclosed my controller so i think i have to remove it to hook it to the pc, plus i need to get a usb serial adapter to connect it. It sounds like that is my next step.

I also noticed the voltage when flooring drops form like 125ish to 100 then goes back up when not pushing on the throttle.

It was also fairly noticeable that the accelerations got weaker throughout the short (maybe 2 mile) drive. For example in my first stop and go test in 1st gear, the ammeter shot up to 350-400 amps much faster than when i tested it again towards the end of the drive.

I'm thinking about just filming a video of me driving so you guys can see how the gauges respond. Its hard for me to tell if what i'm seeing is normal or not since this is my first conversion.


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## alvin (Jul 26, 2008)

On the pot box that arm is crimped tight to the potentiometer shaft. If at 0 throttle if the potentiometer is all the way that direction 5k ohms it will have no effect on the controller till it passes a certain point. That is the point where you would get high pedal fault if that is where the 0 throttle is set. If you loosen the crimp connection of the pot box arm and turn just the potentiometer shaft in the direction of cable travel. Then turn the controller back on. If you get a flashing led back off a little and re-try.

At some point it will get close enough to give you full throttle.

Alvin


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## omonoid (Aug 30, 2009)

ok i think i understand that. Ill try it tomorrow.


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## Ziggythewiz (May 16, 2010)

I think your pot arm is fine. If you were getting a high pedal fault you would be getting no power, not sluggy power.

We do like videos  What is your nominal and fully charged pack voltage? 125V sounds pretty low for a typical config.


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## omonoid (Aug 30, 2009)

Um 135vish im charging now and ill get and exact number when charging is done. They are yellow top optimas by the way. 

Ill do a vid tomorrow before i mess with the lever arm or controller software.


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## alvin (Jul 26, 2008)

I guess I confused you. That was a method to adjust throttle travel only.
I am not saying you have a high pedal fault issue. Everyone knows you would not get power if that was the case.

If you connect your lap top to it you can adjust throttle min , throttle max.

Alvin


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## mora (Nov 11, 2009)

If you end up removing the cover of your controller install a panel mountable serial port to the plastic endplate at the same time. Shouldn't cost much (<2$). Makes connecting controller to a computer easier.

I had fine acceleration even at 96V. 500 motor amps should be available immediately (depending on controller settings of course). So it must be the controller settings that ramp your motor current up too slowly.


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## omonoid (Aug 30, 2009)

Mora:
is the program pretty easy to figure out? Did you use a seriel to usb port to connect it. An further advice on using RTD Explorer would be great.

Thanks


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## adeyo (Jun 6, 2012)

:thumbup: thumbs up on all the advice for omonoid. It's been really helpful for me to read and just learn, as I plan my first conversion. Thanks everyone for chipping in....very insightful!


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## mora (Nov 11, 2009)

omonoid said:


> Mora:
> is the program pretty easy to figure out? Did you use a seriel to usb port to connect it. An further advice on using RTD Explorer would be great.


Yes, program itself is easy to read and understand. You can download it from http://www.evvette.com/EVVette.com/RTD_Explorer.html and try running it on your computer. It won't display any graphs or values but you'll get the idea. See Command list under Help-menu for list of possible commands.

I used serial to usb adapter. It was some cheap one found from local computer store. Works fine, though my eeePC doesn't seem to like it. Sometimes it just refuses to work or hangs if I leave it on for a drive (to get some data). Any other laptop works completely fine without hang ups.

Regarding RTD explorer: note default values before editing them. All the programmed parameters will show up when you type *config* and hit enter. There is no button to revert back to "factory" defaults. You must also save all the changes you've made. Otherwise they will revert back to what they were upon controller restart. Command *save* will do the trick. Before adjusting any throttle endpoint values set current limit to 5 amps (*bat-amps-lim 5*) or something like that. This prevents complete motor runaway in case you misconfigure your throttle values. 5 battery amps shouldn't spin motor too fast. Ask me how I know, heheh. Command *bat-amps-lim 0 *will remove battery amp limit

You'll see your raw throttle values on top right corner. Note the number when foot is off the pedal and when flooring the pedal. Set max throttle value few points off the actual reading so you'll always get full throttle when needed. Same goes for low throttle value. Leave a little play there.

You'll want to make test drive after these adjustments. If it doesn't make any difference you can set *t-pos-gain 8 *and *t-pwm-gain 0* for linear throttle response. After this try experimenting with *ki* value. *kp* should default to zero. *ki* *150 *is what I use. The more the quicker controller tries to match output with pedal position. Too much and it will feel jerky. More info on these can be found at http://ecomodder.com/forum/showthread.php/revolt-control-parameters-15909.html


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## omonoid (Aug 30, 2009)

Thanks! i really appreciate the mini guide. I would not have figured that out easily.

I wanted to test the car the way it is and upload some data before i mess with the config. Ill make sure to be careful about writing down the default values when i do change stuuf.

I went ahead and panel mounted the serial jack and got RTD Explorer up and running easily. I took the car for a 10 min drive and captured the graph data on my pc during the drive. Its as sweet program!! has some potential to possibly make a in dash display using that data.

I tested a few things like starting from 0 mph and accelerating up to speed in both first and second gears.

I went through the captured video and took some screen shots of the tests. If needed i can do this again and be more accurate about the tests. I didn't really log how fast i was going, which next time i will do since it would be good to get a 0 - 40 mph time in different gears.

*Here are some snippets from the test:


Seems sluggish to me. This is how it usually preforms in 2nd during stop and go driving. Makes it hard to get across an intersection in time





















Not positive that i started at 0 mph. Also i don't know for sure if this was 1st gear or 3rd. I tried both at one point. I wasn't actually looking at the computer when this happened so i didn't really know much about it. It just jumped out at me when i went the the screen capture later.











is it a big deal seeing that overtemp warning? It is really hot today (currently 88), and it was the end of the testing, which is probably more rough on the controller than normal driving. Should i think about getting a little pc fan.*


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## Ziggythewiz (May 16, 2010)

Nice data capture! I'll let the expert chime in on reading it properly. To me it looks like in 1st gear you get the RPMs up quick (which drives up the battery current), similar to what I see in 2nd, but your numbers in 2nd closer resemble what I'd expect from 3rd or 4th.

How heavy is the car, and do you know what your gear ratios are?

What units is the temp reading? 88 deg? Sounds like it's toasty there if that's your night-time low  You could certainly benefit from a PC fan or two on the heatsink, since it seems to rise and hold well above ambient.


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## mora (Nov 11, 2009)

Current feedback tells you are getting 500 motor amps. Battery amps will rise as soon as you gain more rpm and pwm goes up at the same time. Max calculated throttle value is something like 510 and you are pretty close to it. I'd say controller works as it should. Though user MPaulHolmes is the only person to give you right answer to your question, hehe. You could try increasing *c-rr* value (current ramp rate). I can't see/feel any difference no matter what number I set that value to.

What brand/model motor you have there?

Controller will cut back power if overtemp point is reached. I've never reached that point even after ~28 miles of highway driving or 30min of stop'n'go traffic. Ambient temp was 95F (35C) during stop'n'go test and heatsink temp was 122F (50C) afterwards. I have no fans but large finned heatsink.

Dash display for that controller is already made. See http://ecomodder.com/forum/showthread.php/lcd-instrumentation-cougar-controller-16132.html


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## omonoid (Aug 30, 2009)

Ziggythewiz	:


> How heavy is the car, and do you know what your gear ratios are?


I'd guess 2100, but i dont know. I used 10 Optima yellow tops which weigh only 43 lbs, and i used an 8" ADC motor which is 107 lbs. according to wikipedia, my car's curb weight is 2200ish, so total is maybe 2300 - 2400.



> What units is the temp reading?


donno. mora, do you know?
I live in Spokane, Wa and it was noonish when i ran the tests. It usually doesn't get hotter than 80 here, but i may look into some heatsink

Mora:

I emailed Paul about it, and i'm still awaiting a response. Ill just leave it for now. It sounds like it's working as it should for the most part.



> What brand/model motor you have there?


8" ADC



> I have no fans but large finned heatsink.


got any info on that, i may look into getting or making one.



> Dash display for that controller is already made.


That's awesome. I might build one. Is there any sort of BMS?


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## jyanof (Nov 11, 2008)

Yep, the controller is pegged at 500A and the vehicle is still accelerating slowly. Obviously, nothing is wrong with the controller or batteries. 

You may benefit a little from better heatsinking - the controller with reduce current output if it overtemps, so if it feels sluggish after a while, that could be a problem. 

However, you really shouldn't be approaching overtemp conditions, especially with your ambient temps. For example, my controller (same one, with over 10k miles) will peak at 500A during accelerations, briefly, but will cruise at around 200-250A. Typically, the controller will run about 20F above ambient for me, maybe 25F in stop and go traffic. So, even in the hot AZ summers, I'm still 20-30F away from the overtemp condition. And, I'm running at higher voltage (144V) which causes the controller to run hotter.

at this point, stay with the lower gears and keep the rpms high to keep the motor amps down. It sounds like your shunt is in the battery loop - you can move it to the motor loop to measure motor amps.

Also, your motor may be too small. That might be tough to swallow, but it seems like it isn't producing enough torque at for the amount of amps being thrown at it.


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## jyanof (Nov 11, 2008)

For controller temp in RTD explorer, it's displayed in the bottom right corner. The raw units in the graph are the actual ADC measurements. RTD converts that to an actual temp (both C and F) and displays it at the bottom right.


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## PStechPaul (May 1, 2012)

I'm not an expert on this controller or DC traction motors, but AFAIK the motor current should jump to maximum almost as soon as you mash the pedal. It appears to be doing that if you can believe the controller reading. I think the gearing may be wrong. What is the motor RPM and the vehicle speed at the first shift point? Maybe the current reading is wrong. Can you read the motor current separately from battery current?

You can get an inexpensive clip-on inductive ammeter for about $16:

http://www.tool-home.com/products/catalog/product_info.php/cPath/929_1145/products_id/16134

But for EVs it's probably worth it to get a good one for $50:

http://www.sears.com/craftsman-digital-clamp-on-ammeter/p-03482369000P


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## jyanof (Nov 11, 2008)

PStechPaul said:


> I'm not an expert on this controller or DC traction motors, but AFAIK the battery current should jump to maximum almost as soon as you mash the pedal. The battery current should go DOWN as the RPMs go up, or stay about the same if you are accelerating, until the BEMF is too high for the batteries to overcome. So IMHO the controller is set up to provide a very long delay for torque ramp-up. It should run up to maximum within 1/2 second or so.


Afraid you have that backwards. Motor current will jump up and battery current will rise gradually as the vehicle speed increases until 100% duty cycle and the mosfets are full on. at that point, battery amps are equal to motor amps and they will both gradually fall together as speed increases.

however, with an ADC 8" and 120V, 100% duty cycle may never happen.

Based on the screen shots, the controller is operating correctly.


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## PStechPaul (May 1, 2012)

jyanof said:


> Afraid you have that backwards. Motor current will jump up and battery current will rise gradually as the vehicle speed increases until 100% duty cycle and the mosfets are full on. at that point, battery amps are equal to motor amps and they will both gradually fall together as speed increases.
> 
> however, with an ADC 8" and 120V, 100% duty cycle may never happen.
> 
> Based on the screen shots, the controller is operating correctly.


Yes, you replied while I was correcting that.


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## omonoid (Aug 30, 2009)

good to hear i guess. I wish i knew back when i bought the motor. I probably would have spent a bit more on a 9".

I'd rather not have to cut new cables to move the shunt. I might buy another shunt and toggle which one my meter reads so i can get the motor amps too. Is this ok for EV, inline between controller and motor? It would be easy to install right between the M+ or M- bar and the motor cable
http://www.ebay.com/itm/1PC-EMPRO-6...ultDomain_0&hash=item2a213b35e4#ht_500wt_1288

So there is no easy/cheap way to get a better boost with my current set up, other than loosing weight or upgrading the motor?

EDIT:
oh i just saw your edit PStechpaul. As i just said i have no easy way of getting motor current. I like the idea of using that cheap one just to get a reading. I'm trying to not spend a ton on more tools since it is technically working, and i'm paying for college currently. 

Thanks for the help everyone


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## alvin (Jul 26, 2008)

omonoid

I have using mine for 3 years without fan cooling , the highest I have seen was 120 degrees f. 

I noticed your raw throttle was at 718. Is that with your foot off the pedal? What is in the value space when foot is on the floor. These values are what you use to set throttle max (foot off) throttle min (foot on floor).

You can come off those numbers some. My throttle only has a range from 680 to 610.

I think if you run around with just a little throttle the mosfets get hotter than at full trottle.

Alvin


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## omonoid (Aug 30, 2009)

I forgot to say, my gear Ratios are
1 -3.45
2 - 2.12
3 - 1.44
4 - 1.13
5 - .91/3.34
Final Drive: 3.67

It's considered "close ratio." dont have time now to google what that means


Alvin, so are you saying its better to hold down the throttle than do "quicker taps" so to speak
Ill pay closer attention to my throttle values next test, so i can optimize that.


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## alvin (Jul 26, 2008)

omonoid

On your last sreen shot the config shows throttle min 413 throttle max 683.

Above that where it shows what is going at the time.Your throttle is sitting at 718. You have to press down a good way before you even get to 683.
Which is 0 throttle in the controller. If when you press foot to floor the value reading does not go to 413 then you are not getting full throttle in the controller.

If you can switch off the traction pack you can watch this value change without driving. It shows up in the top right part of the RTD explorer screen.

Alvin


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## omonoid (Aug 30, 2009)

alvin:
check this short vid out (there is sound). Thats easier than me explaining my test results.
https://vimeo.com/47560927
(currently processing for 20 more min)

jyanof: My max temp in that test was about 168 F vs the amb temp of 90. It seems like i may have an overheating problem compared to what everyone else is reporting. Any suggestions


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## alvin (Jul 26, 2008)

omonod

The link said page not found.

What was the raw throttle when you pressed the pedal to the floor?

Alvin


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## omonoid (Aug 30, 2009)

https://vimeo.com/47560927 should work

416 @ max and 718 @ 0

whats throttle vs raw throttle. And can you repeat what i need to change to make it so 0 throttle corresponds to not pushing on the pedal

thanks


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## jyanof (Nov 11, 2008)

PStechPaul said:


> Yes, you replied while I was correcting that.


oops, i'm too fast!


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## jyanof (Nov 11, 2008)

omonoid said:


> jyanof: My max temp in that test was about 168 F vs the amb temp of 90. It seems like i may have an overheating problem compared to what everyone else is reporting. Any suggestions


Well, most of your problems with temperature are because the controller is putting out so much current. A heatsink would help (i got an aluminum extrusion off ebay) but you should do your best to keep the current down.

I thought i had a better picture, but this is my heatsink - the curtis has since been replaced with the DIY controller. There are fans underneath.










just to prove i'm actually using the DIY controller...









To keep things cool, try shifting gears so that the motor rpms are as high. Not sure what your motor is rated, but I keep my Impulse 9 around 5k rpms while cruising and a smaller motor should surely handle something similar. For me, that means I stay in 1st until 25 mph, 2nd to 40 mph, and 3rd to 55 mph. I think my overall gear ratio is a little larger than yours, so you might be able to go faster in the same gear. You also may have a tough time shifting gears without a clutch, but it'll keep your motor amps down - see if you can get down to ~250 while cruising.

As an aside, your motor must be getting hot too, no?

And, that shunt should work fine. I have a 500A 50mv shunt in the motor loop and have used a relay to toggle between that and a battery loop shunt.


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## omonoid (Aug 30, 2009)

I have no way of measuring motor rpms or motor temp. At least i dont think. Is there a cheap way to get that data?

Are there calculations to follow to figure what a good rpm to shoot for is based off my gear ratio and motor size?

I'm thinking maybe stick i small computer fan in the plexyglass sidewall of the controller if space permits, and if i need to, ill add heat sink on the bottom. A fan seems like it would dissipate more heat than heat sink right? plus im adding a fan to my charger so it will be convenient to add a second.


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## jyanof (Nov 11, 2008)

omonoid said:


> I have no way of measuring motor rpms or motor temp. At least i dont think. Is there a cheap way to get that data?
> 
> Are there calculations to follow to figure what a good rpm to shoot for is based off my gear ratio and motor size?
> 
> I'm thinking maybe stick i small computer fan in the plexyglass sidewall of the controller if space permits, and if i need to, ill add heat sink on the bottom. A fan seems like it would dissipate more heat than heat sink right? plus im adding a fan to my charger so it will be convenient to add a second.


here's a speed/motor rpm calculator i found from a quick google search
http://www.advanced-ev.com/Calculators/TireSize/index.html

there's always the hand temp sensor - after a trip, see if you can keep your hand on the motor for a few seconds. If so, definitely good. Or, there are cheap IR thermometers out there for 10-$15. Should give you a ball park idea, anyway.

a fan on the internals would do little, actually. I assume you put the controller together, so you know that the mosfets/diodes are clamped to the aluminum heat spreader which is bolted to the base plate. That's a very good thermal connection from the mosfets to the baseplate. Transferring heat from a heat-source to air is all about maximizing the surface area in contact with the air. Increasing the surface area with a finned heatsink will far surpass the surface area inside the controller and provide a much better cooling mechanism. Not that a fan inside would hurt from a cooling perspective, but you'll subject your controller to a bunch of crap blowing in for only a small gain. No one i know has actually done it though, so maybe try it out and see if it stays any cooler.


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## mora (Nov 11, 2009)

omonoid said:


> Is there any sort of BMS?


Yes, there is ongoing project for BMS. http://ecomodder.com/wiki/index.php..._CellTop_Battery_Management_System_.28Rev1.29 I think nobody has built one yet, at least I haven't seen any installations documented on Ecomodder. That LCD display also has alarm output which could control a relay instead of buzzer. Alarm output is somewhat programmable and will trigger on different temp readings (motor, battery and/or controller) and low SOC reading.

My heatsink is pretty similar to jyanof's. I found it from metal recycler.



> whats throttle vs raw throttle. And can you repeat what i need to change to make it so 0 throttle corresponds to not pushing on the pedal


Throttle is calculated throttle value which includes those t-pwm-gain, t-pos-gain, c-rr and pwm things. This calculation has max value and you are getting the max reading when you floor the throttle.

Raw throttle is what it says, raw potbox reading.

Like alvin mentioned, 718 is your zero throttle position. You could set the limit to 710 instead of 683. You've left a good play there. In your case the value lowers when you move the pedal towards the floor. Full throttle at 416 means you should set limit to 420. Or something close to that. Now your limit is at 413 which you will never reach.

All this will likely make no difference to your acceleration but at least you get 100% full throttle and not 99%. You will also avoid high pedal lockout during startup.

My car is pretty close to 2000lbs and I run 144V/90Ah lithium pack. Even at 96V/90Ah acceleration was fine. I rarely use first gear. I won't believe your ADC 8" is not enough of motor. Maybe your batteries are getting tired or you have a loose/corroded connection somewhere? Has it always been like that slow? Voltage readings from batteries during acceleration would be cool but maybe hard to obtain.


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## alvin (Jul 26, 2008)

omonoid said:


> alvin:
> check this short vid out (there is sound). Thats easier than me explaining my test results.
> https://vimeo.com/47560927
> (currently processing for 20 more min)


 
It looks like you are getting nearly full throttle.

It sounds like you are really straining to push the accelerator with your foot.


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## Ziggythewiz (May 16, 2010)

omonoid said:


> I have no way of measuring motor rpms or motor temp. At least i dont think. Is there a cheap way to get that data?
> 
> Are there calculations to follow to figure what a good rpm to shoot for is based off my gear ratio and motor size?
> 
> I'm thinking maybe stick i small computer fan in the plexyglass sidewall of the controller if space permits, and if i need to, ill add heat sink on the bottom. A fan seems like it would dissipate more heat than heat sink right? plus im adding a fan to my charger so it will be convenient to add a second.


The cheap way to measure RPMs is to research your gear ratios, then find the right formulas (they are here and all over google) to turn your MPH into motor RPM. Then you will know what your RPMs are at a given speed and gear.

You need a heat sink. A fan only provides air flow over surface area, but if you have no surface area that will do nothing. You can get a nice aluminum heat sink on ebay with 1.5-2" fins for around $20-30. Then if necessary you can add a fan to that for even more cooling. I didn't need to; my heat sink never gets hot.


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