Lifeop4 battery storage .

[peter247]

Hi , Sure this as been ask hundreds of time before , For long term storage should you store them at 60% or 100%. ( 3 or 4 months , over winter )
Some say 60% some say 60% to 100% and some just store fully charge ?
Is there any problems with storing a life battery at fully charged state , I know with LiPo's that is a definite , NO , NO , never leave them flat or fully charged .

 

[rhino]

You can see on the data sheet for EVE cells which should be similar to others it states:

7 Storage
Batteries should be stored (more than 1 month) indoor with a dry and clean environment at 0°C ~35°C. Avoiding contact with corrosive substances and staying away from fire and heat source. The battery should be charged and discharged every 6 months. The storage SOC is between 30 ~ 50% .

 

[sunshine_eggo]

30-70% SoC, room temp or lower.

 

[Donnybrook]

There seems to be a lot of options on storage and I would like someone knowledgeable to weigh in. LiFePO4 when not in use for a month can be stored at 100% SOC? Some say between 80-20%. Others say 80%, period. Li-ion and NiMH have a different set of parameters. Many elect cars recommend not regularly charging to 100%.

 

[sunshine_eggo]

All Lithium chemistries degrade being held at high states of charge and high temperatures. Both together, and it's ugly. One or the other, it's less significant. 100% @ room temp for a couple months? Probably fine. Installing a backup system that may only cycle a few times a year - you'll see measurable degradation after a year of being at 100%. Chemistries, manufacturers and formulations will all be a little different.

"don't charge to 100%" is because most batteries experience the maximum damage from normal operation during charging and more so charging to high SoC. The fact that LFP gets nearly fully charged at 3.65V/cell is a key reason why it has improved cycle life over the 4.20V of NCA, NCM, LMO, etc., chemistries. The first LFP cells were ran from 2.0-4.2V/cell, and they didn't do so well.

If you have a battery with a warranty, follow their storage instructions - usually store fully charged and recharge every 3-6 months or something like that.

NiMH? WTF? Why?