Got MIMA running... why is IMA still holding out on me?

RobertSmalls · 08-12-2010, 07:42 PM

I got my MIMA controller assembled, and mostly up and running, so I took it for a test drive.

so far, but not yet

.

I push the stick forward, and I get full assist, but after a few seconds, it cuts down on the amount of assist it will give me, just like stock.

It's actually quite limiting. On a six mile round trip, I started with 19 bars SoC (fresh off the charger) and ended with 19 bars (probably on the verge of dropping to 1

. I got 90mpg + some Wh/mi instead of the usual 60mpg.

Of course I tried out the fuel injector toggle switch, but the result was predictably disappointing when assist cuts out after a few seconds. Though one of the porch-sitters I passed said "hey, an electric car!" Close enough.

I have four digital probes on each hand, so I touched one of them to the battery and inverter heatsink housing after the run. Both were near local ambient, 90°F.

I presume there's something wrong. Where should I start looking?

P.S. I should add that I opted to assemble my own MIMA controller, and I haven't yet sent it to Mike for testing and calibration. I also have the wrong size pot in place for the battery amps, so I can't calibrate MIMA's amps gauge yet. But I believe this problem is external to the controller.

RobertSmalls · 08-13-2010, 01:51 PM

I believe this is consistent with having the stock MAMODE1 signal, which would suggest a problem with my controller, in the vicinity of the MAMODE1 relay. I'll see what I can do.

RobertSmalls · 08-13-2010, 06:47 PM

Had a negative recal from 10 bars as I was pulling in to the driveway. I chuckled at the perfect timing, and I hit the fuel kill switch and Flintstoned it into the garage.

Maybe I was just asking for more assist than the IMA battery could put out at that time. MAMODE1 relay checks out fine.

I'll get it all sorted out eventually.

Artric · 08-14-2010, 12:37 PM

Wow, a negative recal from 10 bars?! Do you have a grid charger?

RobertSmalls · 08-14-2010, 12:50 PM

Yep. I don't hold the stock SoC gauge to be accurate at all. Positive and negative recals all the time.

How long can you hold 100A of discharge, starting with a full battery?

Artric · 08-14-2010, 01:55 PM

Not long at all, but I haven't really tested it because I'm very prudent with the electric

. Maybe I'll try it out on another tank and let you know.

There's supposed to be no limit, to my understanding, at least with the purchased MIMA kit.

RobertSmalls · 08-14-2010, 09:13 PM

But more than 15s, huh?

Mike Dabrowski 2000 · 08-15-2010, 07:31 AM

Robert, as we discussed in private e-mail, your controller has problems, and I would advise that you send it to me so I can give it a thorough test.I test every controller by running it through a complete operational test on the bench. I would not consider putting a board in a car before that test. Same with the harness.
It is so easy to damage the electronics of the car if the board has serious issues like yours seems to have.
On a good battery pack, one can draw full assist for several minutes.

RobertSmalls · 08-15-2010, 10:01 AM

I'm sure you're right, and I plan to send it to you after I replace that 20K pot with a 5K and finish testing the harness.

**MN Driver** · 08-15-2010, 12:06 PM

Quote:

Originally Posted by RobertSmalls

Had a negative recal from 10 bars as I was pulling in to the driveway.

Separate of your MIMA issues, if this happened after a positive recal with a grid charge to where you knew it was full, you might have some checking to do on your battery pack. ...unless you think your issue with the MIMA caused this.