LiPo charging question

[sirrith]

Hi, I just bought myself an Imax B6AC charger and a G&P (intellect) 7.4v 1200 30C battery.  Plugged the battery in and did a balance charge, and now it says "finished" but it only shows 438mah, and it's also showing 8.48v.  I can't really figure out the manual as it is in rather poor English.  Is this normal? 

Thanks. 

[Stuey]

Probably wasn't flat when you got it.

 

I've no idea if the capacity counting is accurate or not (I'm leaning towards not).

[Libris]

The maximum charge per cell should be 4.20v or 8.4v in this case since their are two cells in a 7.4v lipo. There should be a storage mode on the lipo charge section. Run it at that and it should, eventually, drop the voltage to 7.6v. Then recharge the battery in balance mode. It should come back up to 8.4v. Bear in mind though, 8.48v is less than 1% different from 8.4v. Don't leave the battery fully charged unless you're using it fairly soon that's what storage mode is for.

[sirrith]

The maximum charge per cell should be 4.20v or 8.4v in this case since their are two cells in a 7.4v lipo. There should be a storage mode on the lipo charge section. Run it at that and it should, eventually, drop the voltage to 7.6v. Then recharge the battery in balance mode. It should come back up to 8.4v. Bear in mind though, 8.48v is less than 1% different from 8.4v. Don't leave the battery fully charged unless you're using it fairly soon that's what storage mode is for.

Ah, I had no idea that the voltage would go over 7.4 when charged.  That clears it up, thanks.  So if I want to store the battery now, I just plug it in to the charger and select the storage option, and it will discharge the battery to a good level for storage?  I was under the impression the storage function only charged the battery, not discharged it.  Thanks for the help!

[Libris]

When fully charged a lipo is a relatively fragile beast and susceptible to puffing up quite badly if left for a while at this level. The storage option sets the voltage to 7.6v which which gives the battery a reasonable level of charge so that even over a long time it will be unlikely to go flat. Flat Lipos are more often than not dead lipos. You should never discharge a lipo to below 3v per cell; below that it's unlikely to be revivable and you have effectively killed your battery. Get a lipo alarm if you are going to be using the gun extensively over a day to warn you of this. I haven't bothered with them because I usually turn up at a skirmish (when I can be arsed) with a car load off weapons so it's unlikely that I'd discharge the lipo in any one of them to any great extent.