Initial NiMH Parallel Testing

[uhtrinity]

****** be careful if you decide to do any of the stuff I explain below, you can be killed or your car damaged. High voltage is involved, as well as potentially volatile batteries. ******


Well, due to being on spring break and being very bored I took the next step. After fully cycling my old Insight subpacks, and getting results of 5800 - 6000 mAh I decided to put them pack in the Civic case. Some subpacks had to be cycled a few more times than others. The longest taking 3 cycles. It looks like the 7 - 8 year degradation amounted to about 5 - 10% capacity loss (the -15% subpacks being cycled a 2nd and 3rd time).

I used the Civic case, with the extra components removed from from the output side. The only things I left was the 100 amp fuse and switch along with its protective cover. I also left the (-) output block, the (+) cable was connected directly to the battery post. This allowed quick switching off, and fuse protection. I also had some 6 foot, 8 gauge cable with loop connectors made, I also soldered the connectors to make sure it had the best connection possible. All of the DC to DC circuitry was removed. The PTC strips haven't implemented yet.

On the first attempt I connected directly to the (+) and (-) terminals on top of the Insight pack. This wasn't my first choice as I wanted to connect the positive cable below the high voltage relay, but above the black current sensor. This resulted in an IMA light and a P1440 code as soon as there was assist of any kind.

On the second attempt I connected the positive cable on the bottom terminal of the hv relay. This resulted in a fully driveable car, with one exception that I will mention below. As I expected (and hoped), by connecting to the bottom relay terminal and above the white current sensor, the mima display only showed max 50% charge and 50% assist (though both batteries were doing 100% combined). If I shut off the booster pack it would jump to 100% / 100% like normal. The stock assist / regen gauge also worked like normal going full range. So it did fool the system into thinking it was running one 5 - 6 aH battery, at least from what the mima display showed. I also didn't see any odd charging / assist behavior on the mima display that would indicate that one battery was charging into the other. Battery temps never went above their initial temperature.

Now, the one problem that I did see. If at any time I went to full assist, whether via mima mode 1 or mode 2, it would generate an IMA light after holding that assist for longer than about 15 seconds. With the booster pack off this doesn't happen. The light would also reset itself after turning the engine off then back on. A positive recal would occur over the next 30 seconds until the soc gauge was back to 18 bars. The car seemed to operate normal as long as assist was not pegged 100% for more than 15 seconds. Mode 2 (pima) also had a lot of torque, again, you just couldn't peg it for too long. Like I stated above the batteries didn't even get warm.

Questions: What is the function of the second black current sensor above the relay output? Could the problem be that the two sensors aren't giving the system matching results? The Civic pack I have only has one white current sensor below the relay. Any ideas what could be generating the IMA light?

edit: Btw, I did 80 mpg 4 miles out and 4 miles back without even trying, soc dropped about 1 bar from start. This was including about 5 restarts to clear IMA codes.

[Artric]

Do you have any pictures of how you made these connections, or instructions for someone who would like to go this same route?

[uhtrinity]

Disregard those connections as they didn't work. There are some schematics linked from Jim Isbells site. There is also another thread where I went into more detail as well as more pictures including mounting the pack.