Paul & Sabrina's cheap DIY 144v motor controller

[Vtecsauce]

Hey Everyone,

I was able to reprogram my controller..

I just wanted to ask... i'm running a forklift pump motor 9" on a dune buggy with 3s 18p lipo battery.. capable of 700amps+

We see peaks of 500 amps at the motor.. however the battery side only pulling in the 200amp range......

i've tried 75v battery & 100v battery... but it feels like theres no power difference..

we are running 1 - 2 or 1-4 gear ratio, sorry i dont recall of hand...

all software current settings for motor, battery, and current pot in the controller are at there max settings...

am i missing anything else... or is this all the power i will see?

thanks

[adamj12b]

Originally Posted by Vtecsauce

Hey Everyone,

I was able to reprogram my controller..

I just wanted to ask... i'm running a forklift pump motor 9" on a dune buggy with 3s 18p lipo battery.. capable of 700amps+

We see peaks of 500 amps at the motor.. however the battery side only pulling in the 200amp range......

i've tried 75v battery & 100v battery... but it feels like theres no power difference..

we are running 1 - 2 or 1-4 gear ratio, sorry i dont recall of hand...

all software current settings for motor, battery, and current pot in the controller are at there max settings...

am i missing anything else... or is this all the power i will see?

thanks

Check out your duty cycle. If you are seeing 500A at the motor and the same time 200A on the battery you are only at 40% or about 204 on the pwm in the controller.

-Adam

[Vtecsauce]

Originally Posted by adamj12b

Check out your duty cycle. If you are seeing 500A at the motor and the same time 200A on the battery you are only at 40% or about 204 on the pwm in the controller.

-Adam

Hi Adam,

can you please explain how to change the pwm setting?

when i tried programing the controller, i could not find the duty cycle setting.. :s

thanks

[adamj12b]

Originally Posted by Vtecsauce

Hi Adam,

can you please explain how to change the pwm setting?

when i tried programing the controller, i could not find the duty cycle setting.. :s

thanks

The duty cycle is what the controller calculates to output a current proportional to the input of the throttle signal. I would check and make sure that the throttle signal (TR) is 0 when throttle is let off and should be 511 at full throttle. DO THIS WITH NO POWER ATTACHED!

If your not mapping the throttle pedal properly, you can have a limited duty cycle and thus reduced power.

-Adam

[harlequin2]

Definitely sounds like your throttle pot is not being moved over its full range. Check that mechanically. ie with the "pedal to the metal" can you still turn the pot some more?

[Vtecsauce]

We are using a 5k pot, from what i understand thats the correct one to use.. so you guys are saying i'm not configured properlly in the software.. i'll check the programming again and let you know

thanks

[MPaulHolmes]

500 motor amps is definitely the most motor amps you can get. One way to increase the battery amps is to try to get high motor amps at high speed. One way to do that is to drive up a really steep hill really really fast... But on flat ground, you would have to be going really fast I think. It's not going to happen from 0-35mph. The battery amps have nothing to do with the car's acceleration though. That's all motor amps. If you want it to accelerate faster, the motor amps have to be higher.

[reissmachinist]

I have been working on my third board and have been stalled for over a year.
because of thermal pad issues. I have just started to see what is available. Some times the smallest things bog down my projects.
I have found digikey bergquist BER180-ND individual pads rated at 1.6 W/m-K for $0.57 ea. They may not conform to irregularities as good as a ber231-nd 1.5 W/m-K pad listed in the power BOM. They both have electrical isolation properties.
I an asking for coment and recomendation of one or the other for the 500 amp board.
Thanks 83 Subaru station wagon EV
has worked pretty good with salvage yard pb and a 2CM77 aircraft generator

[Vtecsauce]

MPaulHolmes:

Here is a print screen of the throttle response with only 12v attached to the controller.

...

The gear ratio we are using is approximately 2.5:1 with teeth 35:14...

I believe we are getting a maximum motor current of 526A...using the hardware limiter board maximum, via the default "0" setting for maximum current.

The voltage measurement to the motor seems to be low...for example if only 1 volt goes to the motor I get only 500watts and not much will happen. The voltage max's out at about 25 volts under a slow moving scenario. By observation it seems that the voltage is not being applied to the motor, however it is readily available on the battery side.

So I guess the question is why is the voltage to the motor side so low? Can the motor be the problem?

Is the voltage being limited by the duty cycle? I am less familiar with how DC brushed motors utilize power, so some insight into how the controller produces the duty cycle would be helpful.

This is my understanding....the mosfets turn on/off at a high frequency; in the duty cycle "on" phase. So shouldn't the voltage rise to match my throttle position? i.e. jammin the throttle to the floor is full voltage, and then the mosfets turn off ? This on/off of the mosfets continues until 500 amps in the "ON" phase is achieved ? Then the "off" phase of the duty cycle occurs. Then the cycle continues?

Thanks in advance.

[Vtecsauce]