Battery Aging

[Sam.MP4]

If you have a Lithium-Ion battery and you leave it inactive for let’s say a year what will happen to it? Will the capacity it can hold at full charge change? Will the battery life decrease faster?

[ThijsKunst]

if the battery is fully charged when you put it away, you're fine. no decreased capacity. it only loses 10-20% of its charge. if its empty when you put it away it might lose some capacity, but not that much. also the capacity will slowly come back if you cycle the battery again

[akio123008]

An unused li-ion battery won't degrade significantly, though if charged, it may lose some of its charge (but that's not really a problem, you just have to recharge it)

 

I believe the recommended charge level for storage of li-ion batteries is something like 3.7-3.9V, so that's like 25-50% charge. That's what these things get shipped at as well. I don't think it would be harmful to store one that's fully charged though.

[ThijsKunst]

4 minutes ago, akio123008 said:

I don't think it would be harmful to store one that's fully charged though.

storing fully charged li-ion cells is perfectly fine. they just lose some of their charge.

 

5 minutes ago, akio123008 said:

like 3.7-3.9V, so that's like 25-50% charge.

more like 50-75% charge

 

th

6 minutes ago, akio123008 said:

That's what these things get shipped at as well.

they ship at 3.7v bc... 1. they dont charge them at the factory and 2. its safer to spotweld / solder on a 33%/50% charged cell than it is to do that on a full one

[Sam.MP4]

12 minutes ago, Bob116 said:

if the battery is fully charged when you put it away, you're fine. no decreased capacity. it only loses 10-20% of its charge. if its empty when you put it away it might lose some capacity, but not that much. also the capacity will slowly come back if you cycle the battery again

Thanks for the help! I bought an Anki Cozmo because I liked Vector, one of their other robots. Since Anki was bought out, they haven’t started manufacturing again and it’s been about a year. Manufacturing isn’t planned to start until sometime near the holiday. So from what I think, you are saying nothing will happen to it even if it’s shipped with 0-50%? Are you saying it might loose some of its capacity it can hold even when recharged but it will come back once he is put on his charger?

[akio123008]

4 minutes ago, Sam.MP4 said:

Are you saying it might loose some of its capacity it can hold even when recharged but it will come back once he is put on his charger?

I think what he meant is:

a) usually the battery doesn't degrade when stored

b) if it does degrade, the capacity loss isn't permanent and former capacity is usually restored after some charge/discharge cycles

 

the above does not go for a battery that's degraded because of usage.

[akio123008]

9 minutes ago, Bob116 said:

more like 50-75% charge

Well I wouldn't say that for the lipos that I use, but the voltages are lower on most cilindrical cells.

[ThijsKunst]

7 minutes ago, akio123008 said:

Well I wouldn't say that for the lipos that I use, but the voltages are lower on most cilindrical cells.

i mostly use  the cylindrical 18650s. 3.7v is about half full and 3.9 is about 65-75%.

[ThijsKunst]

15 minutes ago, akio123008 said:

I think what he meant is:

a) usually the battery doesn't degrade when stored

b) if it does degrade, the capacity loss isn't permanent and former capacity is usually restored after some charge/discharge cycles

 

the above does not go for a battery that's degraded because of usage.

exactly

[Sam.MP4]

14 minutes ago, akio123008 said:

I think what he meant is:

a) usually the battery doesn't degrade when stored

b) if it does degrade, the capacity loss isn't permanent and former capacity is usually restored after some charge/discharge cycles

 

the above does not go for a battery that's degraded because of usage.

So essentially if it has been sitting in an Amzazon warehouse for a year it would most likely just loose some of the percent it had? And even if it did degrade, it would be reversed in a few charge cycles? Thanks for the help!