Paul & Sabrina's cheap DIY 144v motor controller

[slurryguy]

Originally Posted by MPaulHolmes

4.
If 12v supply connected to throttle input:
SAFE & NOT DESTRUCTIVE - There would be at most 0.01 amps flowing. No power to controller. You would just sit there.

Is this still true if someone turns the car on? Is this essentially a high pedal lockout scenario?

[MPaulHolmes]

Is this still true if someone turns the car on? Is this essentially a high pedal lockout scenario?

If there's no 12v supply hooked up to the 12v power, the controller will never allow the main contactor to close, since the microcontroller decides when to close that relay. So, it would be impossible to turn the car on.

[watt-a-mezz]

Hi Paul & Sabrina. Good to hear you are feeling better, hadn't seen any posts lately, wondered what happened. Had a go with "the germ" myself, so I know it is nasty. Have been following along, and am waiting for the day I can place my order for my Electric Wombat...(wombat is cool!). Keep up the good work! Take Care, Watt

[dcb]

slurry, understand that paul is guessing at the answers here. If you want to know for sure, you will have to test it for yourself. There is no substitution for real world testing.

[vinny1989]

Originally Posted by MPaulHolmes

The minimum voltage that you can give the controller for driving the car is 0, and the maximum is about 150v. At 0 volts, your top speed will be pretty low. hehe. But the controller would be perfectly happy with, say, a AA 1.5v battery as the power source for the motor. That's the beauty of powering the controller with the 12v auxiliary battery (but using an isolated DC-DC converter inside the controller). Absolute flexibility with the pack voltage! ya! And if someone uses 600v IGBTs, diodes and caps? Then the allowable battery pack voltage would be 0 to about 550v or so. Otmar, the Zilla maker, suggested to me that isolated DC-DC that we're using.

So... your custom controller could control anything from a bike at 24V to a car at 144v? higher?

If so, awesome. Ill buy one when i can afford it.

[NiHaoMike]

Originally Posted by slurryguy

DEATH WISH 9
Starring Paul "Charles Bronson" Holmes.


*****WARNING!!! EV Enthusiasts and Electronic Geeks should ask small children to leave the room before reading further. This list gets pretty ugly. Adults with weak stomachs may not want to read it at all. The writer of this list is not responsible for any angry rages by overly sensitive readers or for anyone losing control of their bowels. Each reader is responsible for cleaning their own pants if they lose control. YOU HAVE BEEN WARNED!******


Following is a list of the most common, most horrendously abusive ways I could think of that might possibly KILL a controller (and/or other expensive parts of an EV.) My questions to Paul "Charles Bronson" Holmes, is how would the controller handle each situation? Will the controller fail? If the controller fails, will it fail safely?

1. Installer mistakenly hooks the tracktion pack up to the controller with reverse polarity.

2. Installer mistakenly hooks the Accessory Battery up to the controller with reverse polarity.

3. Installer mistakenly hooks traction pack voltage to the Accessory Battery input terminals.

4. Accessory Battery (or traction battery) accidentally hooked up to the throttle input terminals.

5. Installer mistakenly shorts the motor cables to each other by attaching both of them to the same terminal on the motor. Somebody gets in the car, turns it on, and FLOORS IT for 30 seconds.

6. Installer mistakenly hooks the motor to the battery input terminals, and the traction pack to the motor terminals. (or any other possible screwed up combination of connection FUBAR.)

7. Somebody turns on the car, leaves the parking break fully engaged, puts the car in gear, and floors it for 30 seconds.

8. After watching a Football game with a group of guys everyone is getting in their cars to head for home. Of course... the EV driver can't just drive away. He must try to show off. He turns on the car, and tries to do a burnout (it's a testosterone thing) by riding the brake and flooring the accelerator simultaneously.

9. While waiting at a stop light, an extremly attractive girl walks by. Instinctively the guy that's driving decides to show off and rev the motor while the car is sitting in neutral. (It's a testosterone thing.) This person floors it for 30 seconds. (Motor grenade alert?)




I'm confident others may come up with other horrific possibilites that could be added to this list. Feel free to do so.

I think it's very reasonable to think about what happens to the controller when it gets abused in any of these ways.

Why bother trying to protect against all kinds of installation errors? It is the mechanic's responsibility to check to make sure everything is correct. If a mechanic forgets to refill the oil in a normal car and burns up the engine afterwards, should we argue that the car should have protected itself from this mistake? What about accidentally installing the timing belt a few notches off?

The faults that actually should be protected against are those caused by component failure and possibly some driver-related mistakes.

[MPaulHolmes]

Originally Posted by vinny1989

So... your custom controller could control anything from a bike at 24V to a car at 144v? higher?

Yes. I used it to run my electric bike hub motor. Well, with 200v components, you don't want to go much over 144v, since when the pack is full, it's quite a bit higher than 144v. You do need a 12v auxiliary battery for the controller though. The control section uses less than 5 watts, so you could even use the last battery (connected to ground) in your series string to power it, and it's such a puny power requirement that I don't think it would get too out of balance, but I don't know.

DCB: You are right! Many of those controller behaviors are EXPECTED behaviors. Some of the control section behaviors have been tested, but maybe we could make a weenie power section (1 mosfet/diode/cap ) and do all sorts of horrible things to it. Terrible, terrible things... hahaha!

[slurryguy]

Hey relax,

It's been a hot day. Drink a cold beverage of your choice.

Nobody is attempting to tell Paul to design protection against every possible installation error. No worries. I was interested to learn what he thought it could withstand.

My "Death Wish" questions were intended to be fun. It sure seems that Paul took them that way too.

Paul has already designed this controller such that it can probably take more abuse than any commercial controller on the market, if things work out the way he hopes they do. (and I hope they do too.) I'm well aware that there are no guarantees.


Meanwhile, if I think of more silly questions ... I'm going to ask them. It's one of the ways I learn things. I always thought the most stupid question was the one in my head that I was too afraid to ask.


For Example:

Death Wish 10:

What if Oprah dressed in a Bikini and sat on the hood of an EV like a car babe? How would the controller withstand this kind of pressure situation?

[watt-a-mezz]

Originally Posted by slurryguy

Hey relax,

It's been a hot day. Drink a cold beverage of your choice.

Nobody is attempting to tell Paul to design protection against every possible installation error. No worries. I was interested to learn what he thought it could withstand.

My "Death Wish" questions were intended to be fun. It sure seems that Paul took them that way too.

Paul has already designed this controller such that it can probably take more abuse than any commercial controller on the market, if things work out the way he hopes they do. (and I hope they do too.) I'm well aware that there are no guarantees.


Meanwhile, if I think of more silly questions ... I'm going to ask them. It's one of the ways I learn things. I always thought the most stupid question was the one in my head that I was too afraid to ask.


For Example:

Death Wish 10:

What if Oprah dressed in a Bikini and sat on the hood of an EV like a car babe? How would the controller withstand this kind of pressure situation?

OH MY, The Wombat has turned into a POSSUM!!!! By any chance is there a scream circuit in it? Take care, Watt

[NiHaoMike]

Originally Posted by slurryguy

What if Oprah dressed in a Bikini and sat on the hood of an EV like a car babe? How would the controller withstand this kind of pressure situation?

I'd be a lot more worried if Jean Ma did that. (I remember a funny slide in a hypermiling presentation that had a picture very similar to what you're describing with the caption "extra weight".)