lipo battery storage

[kevrev68]

hi i am looking to put my 6s 5000mah into storage. i have a hyperion 1420i charger, in the storage mode what amps can i store charge at? i charge 2 x 6s packs in series at 1c 5.0amps can i do the storage mode the same? thanks kev

[Jez N]

Yes just put it on storage mode and it will charge/discharge to 3.85v per cell

[cjcj1949]

There's nothing special about the storage voltage. It's a good compromise. The lower the volts the better the lipos last, but the more likely they are to go flat. 3.7V should be ok. The temperature is just as important. High temperatures like a car in Summer are very bad. Storing at high volts in the cold is much the same as low volts in the Summer. This is one area that is well understood for lipos. There is a table I can find if anyone wants one.

[NiceBlades]

Table would be useful cjcj1949 please.

[cjcj1949]

Permanent Capacity Loss versus Storage Conditions
Storage Temperature	40% Charge	100% Charge
0 °C (32 °F)	2% loss after 1 year	6% loss after 1 year
25 °C (77 °F)	4% loss after 1 year	20% loss after 1 year
40 °C (104 °F)	15% loss after 1 year	35% loss after 1 year
60 °C (140 °F)	25% loss after 1 year	40% loss after 3 months
Source: BatteryUniversity.com

20% loss means end of life. So we get a 10 year life if we store at low volts in a fridge or 1 year life at full volts at 25 Centigrade. If you have lots of lipos you could store them fully charged in the fridge or with a few lipos it's quicker to store at low volts at room temperature and then charge before use. As lipos improve so much each year, it's probably not worth trying to keep them over two years.

There is a lot of info on the battery university site. It shows the effect of final charge voltage against cycle life and usable capacity. For a shorter life and longer flights charge to 4.30V. For many more shorter flights go for 4.10V.

Another graph I've seen shows lipo death happening at about 5.0V a cell. All lipos are different and there are many ways of destroying them. It is quite easy to spend more time talking about lipos than flying them.