Long-term battery storage strategies?

[Greg Parker]

Many are buying and socking away extra batteries for later or much later use.

I was wondering what strategies others might be using. For instance are these batteries being checked and charged to a particular storage voltage? Are they being stored a cooler temperatures? How long can they be left alone and still be viable with different storage methods?

I usually leave my 6 active batteries charged for short-term storage at 15.2 volts or a little more. That is the default storage voltage for the Hitec X4 charger I use. Some in the past have suggested charging to 4 lights with light 5 flashing. Yet when my charger reads 15.2 volts my 6 batteries show anywhere from 2-3, 3-4 or 4 lights lit. Not sure if this a symptom of the age and condition of the batteries or some inconsistency in the way the number of lights are illuminated.

 

[nvpowerdoc]

I believe the storage voltage for LiPos is 3.7-3.8V/cell, or 14.8-15.2V for a 4S battery pack. Not sure what that correlates to on the Solo Battery (display lights), but from what I recall, the Solo batteries self discharge to a "storage" voltage level after some period of time (reference necessary here). You could fly a Solo with a battery until it reaches the storage voltage and store it at that point. Anytime you store the battery in a "cool" temperature (say 72degF), it will prolong the battery's life.

Just Google LiPo storage - there are many documented sources on prolonging LiPo batteries.

 

[Greg Parker]

Will a Solo battery stay at storage voltage (15.2v) for a year or more?

 

[Jubalr]

Will a Solo battery stay at storage voltage (15.2v) for a year or more?

I don't think it is something to worry about. Otherwise you would have warnings and Born On Dates on the boxes. Some of the batteries being bought today were likely manufactured in the first batch. Properly stored they will last a good while. I found this regarding a test:

I’ve reviewed CBA battery analyzer discharge graphs of packs that were base lined brand new and put in “proper storage” for over 3 years. When CBA tested
again years later the packs were virtually identical to the “brand new” discharge graphs.

 

[my-spot]

...from what I recall, the Solo batteries self discharge to a "storage" voltage level after some period of time (reference necessary here).

To correlate with that statement, I charged three Solo batteries to 100% and then didn't fly until maybe 2+ weeks later; each was down to ≈69%... If they are designed to discharge to "storage" level then it is a nice feature but it begs the question... Since it really isn't always practical to charge to near 50% after a flight, is it better to leave them in a discharged state or charge them and let then discharge to storage levels on their own?

 

[Greg Parker]

To correlate with that statement, I charged three Solo batteries to 100% and then didn't fly until maybe 2+ weeks later; each was down to ≈69%... If they are designed to discharge to "storage" level then it is a nice feature but it begs the question... Since it really isn't always practical to charge to near 50% after a flight, is it better to leave them in a discharged state or charge them and let then discharge to storage levels on their own?

I doubt that putting the extra full charge cycles on the batteries is of any benefit an may shorten their life. As mentioned above many suggest charging to 14.8v to 15.2v. That should be around 3 to 4 lights on most batteries although as I mentioned not all my batteries are consistently lit at 15.2v.

That is one benefit to a charger that will stop at storage voltage.

 

[Greg Parker]

I just opened a recently acquired sealed battery and checked the voltage. It read 15.17 volts and had 4 lights lit. Since it is doubtful that it was made in the last six months it seams that once they drop to storage voltage that they stay there pretty well.

 

[Cuzman]

I had read something once about maybe putting them in the fridge for longer-term storage?

 

[andrew.baker.142]

Storing LiPo batteries is a discharged state is bad. I usually charge them to roughly 50% charge (4 lights) by manually taking them off the charger. If I have fully charged batteries and no plans to go flying soon I usually just go run the batteries down to 50% by hovering in the front yard.


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[Joe Horn]

I just opened a recently acquired sealed battery and checked the voltage. It read 15.17 volts and had 4 lights lit. Since it is doubtful that it was made in the last six months it seems that once they drop to storage voltage that they stay there pretty well.

Its date of manufacture is printed on the bottom of the battery. Flip it over, and look in the very bottom right corner. I've gotten several "new" batteries in still-sealed boxes that were 50% charged when I opened their boxes, and their dates of manufacture were over a year old.