Storage level for batteries

[SOB8604]

Hey gents, so back in early January possibly even late December I had charged all my batteries, however didn't get out to the field early enough before the flakes flew and that was the end of it up until this point, I've had a sh*t ton of stuff on my plate and all but forgot about them until now. I have read a few different things about storing LiPo's, store em full, or at 50%. What do you all do with your batteries for storage, and at this point having been charged full for nearly two months should I be concerned about their life?

55* on Tue and Wed here so we can start melting these feet of snow away!

[WintrSol]

RE: Storage level for batteries

Hey gents, so back in early January possibly even late December I had charged all my batteries, however didn't get out to the field early enough before the flakes flew and that was the end of it up until this point, I've had a sh*t ton of stuff on my plate and all but forgot about them until now. I have read a few different things about storing LiPo's, store em full, or at 50%. What do you all do with your batteries for storage, and at this point having been charged full for nearly two months should I be concerned about their life?

55*  on Tue and Wed here so we can start melting these feet of snow away!

In general, most LiPo batteries will slowly degrade when stored fully charged, or discharged; ideally, they should be around 40-50% charged, which is about 3.8-3.9V per cell. How quickly they degrade has never been pinned down, to my knowledge. So, when you do use them, reduce the time some; maybe 20%. Then, check the cell voltages after use and a few minutes rest. If they are above 3.8V, they are still useable for that duration; if above 3.9V, you can increase the time some, and measure again. Below about 3.7V, and they are possibly failing; they've certainly lost capacity.

[retiredflyer]

RE: Storage level for batteries

I used to keep my batteries at full charge too, until I noticed that they were slowly losing their full capacity. Some even started to expand (like inflate) a bit. Not too good! I eventually got a charger that has a storage setting and that is what I do with all my batteries now for the winter. Even in the flying season, if I don't plan on going out for more than a week, I will put them into storage mode. Usually after flying I will leave them at their discharged level until I go out again the next day or two and charge them up full again, vs. putting them at storage levels.

[SOB8604]

RE: Storage level for batteries

Thanks fellahs,
Where as I don't see myself flying again until probably the end of this month at the earliest would it be worth it to discharge em with my charger than go into storage mode? Or would another few weeks time even make a difference.

[WintrSol]

RE: Storage level for batteries

I always charge or discharge to storage levels if it will be more than one day; so far, my only battery failures have been from accidental over-discharge (lost in a corn field), or mechanical damage. How much more damage another few weeks will do is not defined, but it would still make them last longer if you bled them down to storage level.

[SOB8604]

RE: Storage level for batteries

Thanks WintrSol, I'll bleed em down tomorrow and get em into storage. Thanks

[Tom]

RE: Storage level for batteries

Everyting posted above is correct. I only have one tbing to add. When stored fully charged, IR goes up as the battery degrads. Higher internal resistance will effectively lower the c rating. Your battery may appear dead after a few min of flight but when measured after landing, it can show 3.9v per cell or so. All batteries will do tbis eventually but storing fully charged will accelerate the process. Conversly, storing below 3.8v per cell will do the same damage and uaually a lot more quickly.

[SOB8604]

RE: Storage level for batteries

Thanks Tom!