Storing Lipo Batteries

[Rich D]

Do you guys charge them up before storing for weekly racing, or just leave in what was left after your last run, and then charge again before use ?

[Bungleaio]

I just leave mine after the final till the next week and they've been fine. I've even left them for 5 weeks with no apparent problems.

[Dazzler]

I had a conversation with a guy at Trackpower ages ago when I first brought mine, I was advised that storing with at least 80% charge was good practice. I have never had any problems with any of my LIPO's or seen any degradation in performance.

[mark christopher]

rich
bc6 has a storage mode just for the job!!

[chb]

Originally Posted by Dazzler

I had a conversation with a guy at Trackpower ages ago when I first brought mine, I was advised that storing with at least 80% charge was good practice. I have never had any problems with any of my LIPO's or seen any degradation in performance.

The best advised charge should be 40~50%, not 80%. Sounds like a lot science from that Trakpower guy... or has he any interest in us keeping bateries too long and not buying new ones

Bantam BC6 is great for that indeed ! (it's not the only one that has a storage mode with ~50% charge)

[Dazzler]

Interesting... I read this as I had taken what I was told as correct.. I've took a look on the Trackpower site and they state that their LIPO's ship with 70% charge. Quote 'When you buy a new TrakPower pack it comes around 70% charged. The pack can be charged from new at the normal charge rates' so as you suggested 40 - 50% I thought i'd do a little digging. Kokam are supposed to be one of the best quality cells (Or so we are told by Orion and the likes) so I looked up a couple of their technical data sheets. Kokam quote 'On a storage, Cell state is 40%~50% charge(3.7~3.9V).' So CHB does seem to have a good valid point, I still maintain that I have had no issues however, but then - Time will tell..

Originally Posted by chb

The best advised charge should be 40~50%, not 80%. Sounds like a lot science from that Trakpower guy... or has he any interest in us keeping bateries too long and not buying new ones

Bantam BC6 is great for that indeed ! (it's not the only one that has a storage mode with ~50% charge)

[lambchops]

Do you need to keep them at this level when storing for just 1 week or are we talking long term storage?

[Dazzler]

It doesn't stipulate what duration constitutes storage, but I'd suggest it's good practice for any storage duration, and it means it'll take less time to charge your packs when you need them. I always try to charge mine at the earliest opportunity. One other piece of info I read on the Kokam data sheet, was that storage for longer than 12 months would cause irreversable loss of capacity. Maybe these things have a shelf life based on that fact, but that is not the question being asked..

[dodgydiy]

i bought some lipo packs that had been stored for about six months, were fully charged when stored, have had to charge and discharge them several times to get the cells back in balance, they still time out at 2 hours on charger of which an hour and a quarter is balancing. still out of balance but improving slowly. this is also not due to cells not being balance charged before storage, i know the previous owner well and he did not mistreat them. there doesnt seem to be any loss of capacity or power compared to the identical packs which i already had

[Rich D]

Cheers for the replies guys - particularly the BC6 info

As far as packs not balance charging, i have purchased a total of 8 new lipo packs from two different manufacturers. Two of which have not balanced charged from new and time out at 120 mins. I've not noticed any difference in the performance between packs that charge and packs that don't charge so i haven't bothered pursuing it.

[Marvin]

CHB, I'm not sure where you got that from, but you can store LiPos with any amount of charge in them, providing that they aren't left too long with very little charge (internal resistance, while low, does eventually discharge the pack).

80% or even fully charged is fine for 'storage', but if you're only leaving it for a week or so, the 50%ish that is left in the pack after your last run would be enough.

There is no 'optimal' storage charge, just don't leave a pack with no charge left in it. The 'optimal' charge idea is just made up for those people who are used to the habits of NiMH.