How to recondition an Insight IMA battery pack pt.1

billysan
Posts: 73
Joined: Tue Aug 26, 2008 9:26 pm

How to recondition an Insight IMA battery pack pt.1

Postby billysan » Thu Sep 25, 2008 10:04 pm

MY insight has never been 100% healthy since Ive owned it. Its got almost 120k miles on a 6 year old car and the battery is on its way out. I get frequent battery recalibrations (meaning I loose all motor assist for a good 5 mins) that are happening almost daily now. Whats worse is Honda want over £2500 for a new battery pack :shock:

So Im going to attempt to recondition the battery myself using some off the shelf battery chargers and test equipment.

Tonight I have stripped the back of the car out and now have the battery pack sat on my living room floor. Tomorrow starts the big job of disassembling that and to begin cycling the individual cells!!

I would start tonight but Im tired and the thing has several live terminals with 144v dc on them, and its capable of delivering over 100Amps!! Yikes!

I'll post pictures of how Im getting on anyway for people to follow. Not that I expect everyone to try this, but I thought it might be of interest.

billysan
Posts: 73
Joined: Tue Aug 26, 2008 9:26 pm

Re: How to recondition an Insight IMA battery pack pt.1

Postby billysan » Fri Sep 26, 2008 11:10 pm

Here is the progress made during the first 24 hours.

All the rear covers removed to show the battery pack and associated electrical hardware;

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Battery pack out of the car and sat on my living room floor;

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Pack end removed to show sub packs;

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And this is in essence the battery. It is just 120 D cell rechargable Nimh cells mounted in strings or subpacks of 6 cells. Each cell is 1.2v, 120 of them gives 144v with the ability to deliver over 100A continuous.

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And here begins the reballancing. Using my Triton battery charger/discharger/cycler to deap cycle each subpack hopefully I will be able to restore the cells capacity and get rid of the memory effect they seem to have aquired over time. Its a long drawn out process though, I only cycled this subpack 3 times today and that took almost 11 hours!!

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I need to have the car back on the road for the 16th of next month at the latest so I think I may have my work cut out!!

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Karl
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Re: How to recondition an Insight IMA battery pack pt.1

Postby Karl » Sat Sep 27, 2008 8:06 am

Its amazing to think that the battery pack is really little more than a load of rechargeable "D" batteries - the same things that power my little boy's tonka truck.

Could you not just buy off the shelf replacement D batteries or are they of a different spec?
2015 Skoda Octavia VRS Combi 2.0 TDI 184 DSG in Candy White - 50MPG and climbing

billysan
Posts: 73
Joined: Tue Aug 26, 2008 9:26 pm

Re: How to recondition an Insight IMA battery pack pt.1

Postby billysan » Sat Sep 27, 2008 2:24 pm

Unfortunately its not quite as simple as popping down to wollworths and clearing them out of D cell evereadys. Honda ordered one job lot of there cells from Panasonic for the insight project, or so Ive read. Panasonic want a minimum order of 10'000 to make some more.

The batteries although being 'D' cells are of very high specification compared to consumer batteries. For starters the ends are threaded, they are bolted together. They rated charge capacity is 6500mAh, all combined the battery pack is actually rated at 10kW!!! Then you have to take into account the temperature extremes these batteries are designed to work in, the shock they must be able to take, and the fact that they are designed to have a servicable life in excess of 100'000 charge/discharge cycles. They also have a very low internal resistance unlike consumer batteries, you could blow one up if you shorted it out unlike a normal one which may only think about getting a bit warm. They are rather specialist, hence why they cost so much.

Some very very clever people in the states worked out what I am doing, and indeed Honda does the same when you buy a new battery on an exchange basis from them. Thats why Im saving myself the money and doing it myself. If it was a case of just swapping them with something available I would have gone for that route instead, believe me!!

A friend up in Yorkshire has actually fitted li-ion batteries to his but in doing so has completely written off his spare wheel well and what small amount of boot space the car had to start with. Again this was not cheap.

If all goes according to plan for me here I should have a fully working battery pack for about £300, not including my time.

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