Charging lipos after storage?

[jordan...]

Hi,

Sorry for the noob question, but i am still fairly new to lipo's. I have found through searching that if lipo's aren't being used they should be stored at 50-60% capacity.

My question is, when you go to use a stored lipo, do you charge it to 100% from the charge level that is already stored, or do you run it from 50-60% down till the lvc, before giving it a full charge?

hope that makes sense
jordan

[BrianG]

Either way is fine, but charging them back up to 100% is fine...

Hey BrianG, i want to know, when you store lipo at 50-60% of their capacity, what's the way to know that the pack is at 60% of this cap
Is it 60% of the capacity of the pack in mAh, or 60% of the nominal voltage

Hey!!!!!!! why i have this line on my post

[JaySki]

Originally Posted by david lamontagn

Hey BrianG, i want to know, when you store lipo at 50-60% of their capacity, what's the way to know that the pack is at 60% of this cap
Is it 60% of the capacity of the pack in mAh, or 60% of the nominal voltage

It would be whatever 60% of the packs rated mAh is....
Basic math would say....an 8000mAh pack would be charged to 4800mAh, a 6000mAh pack would need to go to 3600mAh.

Hummmmmm!!! not sure, i think that each cell must be charge at a voltage of 3.7 volts or 3.9.................. do not remember

[JaySki]

Lipo is charged to 4.2V as a general "Rest" voltage but is actually rated at 3.7V under load and should maintain that voltgae or very close to it until the batteries energy mAh starts to drop. This is why LVC's are used.. Once the batteries energy(or large bulk of it) is used up, the voltage will start to drop pretty quickly.
SO.. Storage charge isn't based on the voltage, as it is always the same... but based on how much energy is put back into the battery... thus 60% of the batteries capacity.

I just tell my 0610i TCS setting 60% (or whatever) and let it do the rest.

I don't get to run a lot due to my business and I routinely charge my lipos from storage and then use them. Haven't seen any adverse effects from doing it this way - been most of the past yr and a half.

[jnev]

Lipo's should usually be stored at about 3.8 volts per cell. However, you don't need to keep them at this voltage unless its for about 3 or 4 weeks or more.

Can anyone explain why it's better to store them with less than full charge?

[BrianG]

Excerpt from http://www.batteryuniversity.com:

Originally Posted by batteryuniversity.com

-The time at which the battery stays at 4.20/cell should be as short as possible. Prolonged high voltage promotes corrosion, especially at elevated temperatures. Spinel is less sensitive to high voltage.

So, keeping the cell at half charge ensures the voltage to be at the nominal value. I'm sure you could discharge as needed until the open-circuit resting voltage is ~3.7v...

thank you, very good infos