Battery Died

[alan0043]

Hi Everyone,

I have a rookie question or too for you guys. I went to my supply of batteries and picked out a battery and found out it was died. Actual there were two batteries died. The battery (actually both batteries) in question is a Tattu 850mAh 75c. Why did they died ? What would drain the battery when not in use ?

All info is good,
Al

 

[JasonK]

did you run a storage setting on your charger before putting them in storage? if not - what per cell voltage were they at?
how long where they in storage?
could something have shorted them?

 

[alan0043]

did you run a storage setting on your charger before putting them in storage? if not - what per cell voltage were they at?
how long where they in storage?
could something have shorted them?

Hi Jason,

I do not know that a storage setting is. Can you please explain. The other 4 batteries that are the same as the 2 died batteries are ok. The batteries in question where in storage for about less then 3 months. I thought I had all the batteries fully charged before I stopped using them. Still open to more thoughts.

 

[JasonK]

Hi Jason,

I do not know that a storage setting is. Can you please explain. The other 4 batteries that are the same as the 2 died batteries are ok. The batteries in question where in storage for about less then 3 months. I thought I had all the batteries fully charged before I stopped using them. Still open to more thoughts.

lipo batteries are best stored at around 50% charge, any good charger has as storage setting. When your done with your batteries and are going to have them in storage, it is best to run them on the storage setting on your charger. If they are low/empty, they are likely to end up under voltage and damaged. If they are full, it will hasten the wear on the battery, meaning it will loose capacity faster.

 

[quorneng]

alan0043
The advantage of using the storage setting on a charger is that it 'balance' charges or discharges each cell to exactly the same storage level, normally 3.85V.
This is important as LiPo do slowly self discharge so if a cell is near fully discharged at say 3.6V after a few months it may have dropped below the 3.3 'damage' level. It is recommended that a LiPo in storage is given a storage charge every 3 months to ensure no cell voltage drops too far.
Leaving a LiPo for even a week or two anywhere near full charge is also likely to damage it from unwanted internal chemical reactions as does extreme heavy usage.
A LiPo is very powerful for its weight but needs careful attention to get the best out of it.
Finally beware actually using the maximum discharge rates that may be claimed (its C rating).
For an 850 mAh at 75c would be delivering .85 x 75 = 63.75A . I would be surprised if it really could or even that the battery wires were big enough to handle that many amps. In any case it could only do it for less than a minute before it would be fully discharged. It would also by then be pretty hot & excess heat damages a LiPo faster than almost anything.