Charging per cell on Lipos

[ducati777]

Hi all,

I'm making the switch to brushless, and also to Lipo batteries as many of you have.

Has anyone tried one of these chargers that charges each cell individually? I'm trying to reduce my chance of fire to zero...

check out this charger...

Charger Link (http://www.amondotech.com/index.asp?PageAction=VIEWCATS&Category=304)

[tcolesen]

I wouldn't use any of those. The one charger that does the individual charging would only work with their packs. And it can only go up to 1.5amps. So, to charge any normal RC car pack, it would take over 2 hours. I suggest a minimum of an Apache 2500. It is the charger I use. Even though its 2.5amp rate is still slow, it is a very good and small charger for $50:
http://www.aircraft-world.com/shopexd.asp?id=454 Theire shipping is pretty cheap from Japan.

There are others, like the Duratrax Ice (8amp, 1-4cells), and the Astroflight 109 (8amps, 1-9cells). These 2 chargers cost about $120-130.

You can check the cell balance via taps that can be built into the pack. Keeping a pack in balance is a good safety thing. My 3s 4500mah lipo pack has been in perfect balance for the last few runs, and I check it using individual cell taps.

[ducati777]

Well I plan on using the polyquest 1800 3s, and it comes with the plug built into the pack already.

Dang, no one seems to like charging each cell individually, but it seems like the safest way to me.

[tcolesen]

I have done that with my 3s pack. I built the pack myself, and installed a tap on each set of parallel cells (3 taps total). I don't charge them individually anymore, but I monitor the individual cell voltage via the taps. If you have balancers, then those will work to make sure that the voltage on each cell won't go too high.

[ducati777]

Well I don't have a balancer or even a charger yet... BUT...

What I'm thinkin is a normal charger, will charge in series. I'll have one of those PCM charge guards, which will tell me if they get out of balance. Thats all well in good, but once out of balance, don't I just charge each cell individually to get it back in balance?

If thats the case, then one would think a charger that always charges per cell would be better... plus it would be impossible to cook a cell at over 4.2 volts, as the charger doesn't exceed that per channel unlike a series charger that puts out 12.6 volts through all 3.

I guess what I'm really wondering, is given 2 chargers of the same price, one charges in series, and the other in paralelle, wouldn't you always want to go with the paralelle? I'd think so, but I haven't found anyone who agrees.

[starluckrc]

Many aircraft guys charge there packs as a single cell pack. You just need to be sure that the cells are at the same voltages before hooking them in parallel. Unless you have a high current charger, you may be charging for quite a while as well. Be sure to get the wiring right as well so you don't short your packs.

[ducati777]

Heheh get the wiring right eh? They come wired from the factory so I'll definately have words if they aren't right. Anyway my biggest fear is fire, which is probably pretty common. I think I'll go with a paralelle charger like the one above. On the plus side the one above monitors each cell individually, so even if they're off going in, it ought to charge them up equally. I'll still check voltages as much as I can though, better safe then fire.

I've been staring at my RC18T, and I'm already thinkin about how I can get 2 packs on it at once... Talk about stupid long run times, it would be a 3s2p setup with 3600 mah on an 18th scale!! Anyway thats more idle day dreaming than a planned project. But who knows I just might get bored with a dremel one day.