$550 battery rebuild?

[Corey872]

Hey all - had a few free minutes today and was reading the forum (specifically the "most mile on the battery pack" thread) and started considering the inevitable death of the IMA pack.

Got to searching around the internet and found:
http://batteryspace.com/index.asp?PageA ... ProdID=709

Basically – 1.2V NIMH battery, 10000mAh, with solder tabs - $4.51 ea in quantity of 100+

So it seems at though 120 of those would come in at under $550 and give about a 35% boost in battery capacity. Has anybody actually rebuilt their own battery pack? Also what do you think the cars computer would think about the extra capacity? It seems to me that if the ECU is looking mainly at volts you might be able to get away with it.?

[Aaron Cake]

As has been mentioned before, solder tabs are not capable of handling the currents that the Insight requires. You're pulling about 100A from the pack at full assist, which will basically turn solder tabs into metal vapour. Note how the stock batteries bolt together. One side has a inner thread, the other side has an outer thread and each battery screws into the next. These connections are able to handle the high currents.

Also, adding extra capacity isn't much of an advantage either. Since the BCM tracks current in and out of the pack to calculate SOC, it knows that the battery should be ~7AH. Adding a 10AH back will simply result in a wasted 3AH of capacity.

There MAY be away to "fool" the current sensor during regen to convince the BCM to put more juice into the pack. This would involve sensing regen (easy enough...) and controlling the voltage output from the current sensor to the ECM and BCM. In theory, you could might be able to do the same thing in reverse to get that extra capacity back. But I have not really looked into this, since I am looking more heavily into experimenting with a variation of the MIMA control...