Hello all, I have my first lipo set up and I received my battery and charger the other day... The batteries came set a 3.8v per cell.. THe battery is 2cell 7.4v 5000m? I was just curious cuz essentially the batteries came fully charged and I wasnt sure if they were full voltage? Is there a clear cut way to know what each cell should be too? thanks again...

It's only partially charged. 4.2v per cell is around the norm for a fully charged lipo.

Lipos can be confusing - there are at least 2 voltages tossed around that can confuse. When lipo is talked about - the 3.7v, 7.4v, 11.1v - that the "nominal" voltage and its mainly used just to compare. The fully charged lio cell voltage is 4.2v. SOme chargers will let you charge to 4.24v or so, but most chargers charge close to 4.2v/cell. The 2S then is 8.4v, 3S - 12.6v and so on. There is also a minimum voltage as well (~3v/cell).

I've read nominal voltage is supposed to be the voltage of a charged cell under load.

3.8v is a partial charge and new lipos usually come partially charged.

Thank you guys alot... DUster you are a class act answering all these questions for us...

3.85v is also the voltage you should charge them to if storing them for more than a week or so

Cheers

Be aware that for SMC lipos, SMC specifies 3.6v/cell. 3.85v is not universal, its good, but so is 3.7-3.8v unless the lipo is an SMC. SMC maintains their lipos are diff. This is a quote from Bryan, the SMC rep, taken from a long winded post in the electric offroad forum -

"Bryan: For our Lipo's, discharge them to around 7.2v area, don't worry about the rated capacity, we go by voltage. Then once a month or month and a half, fully charge and discharge them to cycle the chemicals in the cells to prevent them from prematurely wearing out. Lipo's do not have the discharge issues that NimH do, so if you leave 1000mAh 7.2v alone and check it a two months later, its gonna be pretty much within .1-.2 V from where you left it."

SMC also advises that their lipos not be charged unless ready to run.


My chargers (Hyperion) storage function is %'age based, not sure how many are voltage based, but I store lipos (months) at 70-80%.