I replaced the entire hybrid battery pack of my 2008 Prius at a Toyota dealership and kept the original swapped out battery. Now I need to figure what to do with the old one. My line of thinking in keeping it was that the car is 10 years old (with very low millage, around 55K) and it's still worth the cost of a new battery, but if this happens in let's say 5 years, it won't be. Then, the older battery could be of some use (why? see additional info). Is it safe for storage though? I have a storage space in my building where I can keep it, completely sheltered but not AC controlled (non-extreme temperatures though). Is it safe to store there? Is the battery even going to be any good in 5 years time? Additional info: I think the battery is fine other than the bus-bar. The mechanic at the dealership said the battery is acting out because one cell "reversed its polarity" going from positive to negative (which sounded like improbable bullshit and he couldn't explain how that's even possible, but we couldn't find a non-toyota mechanic to open it up and fix it - so we changed the entire thing). Now, I opened up the battery pack case and the bus-bar is heavily corroded, so voltage probably wasn't measured correctly. Also, the troubles with this battery started immediately after the car was driven off-road and got smacked in the bottom by a rock, is it possible that this loosened the bus-bar? I really can't think of a possible scenario where a cell suddenly reverses its polarity. The mechanic mentioned he has never seen this before, but didn't seem to know his ways around those batteries other than swap the old one out and put a new one in... Has anyone ever encountered this? Thanks for any input!
I don't know about the reversing polarity thing - but a quick search on google shows it is possible on a lead/acid battery. As for the battery being good in 5 years - meh. I would think you would need to discharge/charge that pack in some way and if the corrosion is already there....? If I were you, I'd tear that battery down and sell the packs, or take it back to a Toyota dealership and see if it's not too late to recoup the core charge.
If one cell in a pack has significantly less capacity than the others, then it can discharge completely while the pack is still outputting power. The current being forced through the dead cell acts as a charge current in the wrong direction, thus a reversed cell. Since the prius uses only a fraction of the total capacity, this should be very unlikely to occur. Posted via the PriusChat mobile app.
Yes, it does happen and is the number 1 reason for rendering a module useless. One bad module takes out the whole battery.
I don't think storing a 10 year old hybrid battery, that has already failed (regardless of reason) with expectations that it would be "worth it" in 5 years is worth the trouble.
Oh yeah, they refused to give any credit at all for the original battery, that's the reason I kept it (which they tried to prevent btw). It's possible to buy a new bus-bar though. In any case, it has been a couple of months now since removing the battery. Have the cells self-discharge themselves significantly by now? If so, I'm guessing it'd be difficult measuring their capacity etc. Any workarounds?
yeah how come the dealer let you keep the old pack? Cell reversal is common. And the clock is ticking on that old battery. Your line of thinking its worth the cost of a new battery is nutty. Its an ancient battery with severe corrosion issues which usually means a pack is leaking electrolyte. Sell it on Craigs list to a whack a moler.
