Lipo charge Q.

[ducati777]

I know I know! Another Lipo thread... anyway I think I got something new.

Everyone keeps saying don't leave a Lipo unattended, I say don't leave it somewhere flamable. If it goes up, its going to burn whether I'm watching or not. Thus I always charge in fireproof areas, but I may or may not be watching.

When I'm not I worry about damaging the pack. But with the PQ charge guard in place, I can't go above 12.6 volts on the pack right? Or else the guard will trip it, thus I shouldn't worry too much about not disconnecting the pack right when the buzzer goes off.

Is this right, or is there risk to the pack from being left on "trickle" charge even though its limited by voltage by the guard? Remember I got the fire side handled, lets not get caught up on that.

[tcolesen]

If you want to learn A LOT about Lipo charge/storage safety, check out the RC Groups "Battery and Charger Forum":
http://www.rcgroups.com

Charging in a fireproof place is a very good idea. I personally don't do it, but I do monitor the charging. If a battery burns and you are there, you could throw sand or some other flame deterent on it. Smoke will be a problem though, so taking it outdoors (if possible) would be a very good idea.

The PQ charge guard doesn't really add much in the way of safety. It makes it so that if one cell in the pack gets to about 4.30v, the charging will end (or whatever it does). The charge guard just prevents severe overdischarge for individual cells (caused by imbalances in the individual cells). It is in no way a balancer that makes the battery more safe to use. Also, 4.30v really is too high. 4.25v and higher is considered to be where the battery chemistry becomes unstable, to the point where it can be dangerous.

There really isn't such a thing as "trickle" charging for a Lipo. What this term commonly refers to is the slow tapering off of the charge rate during the CV (constant voltage) mode of the charge process. This can be thought of as topping off a battery.