Lipo battery care tips

[bearcat]

I didn't know some of these myself. Check out these Lipo battery tips.

1) Never let the batteries run down lower than 70%. Once the battery is low, the chemical reaction happens, the resistance goes up, and the battery deteriorates very fast.
2) Never store the batteries in full charge. Battery will not discharge because it is not active.
3) Never store the batteries lower than 3.7V/cell. Battery cannot be charged back when the voltage is too low.
4) Store the batteries in half charged, between 3.8-3.9v


...And there's one more. Lipos will last longer if they're balanced. That's what that other spare plug is for on them. A balancer plugs into that to keep an equal amount of energy in each cell at all times. With as much as lipos can cost, a balancer could be a good investment.

[bearcat]

This is different from Nicad batteries, which have to be completely drained before you recharge them. You never want to completely drain Lipos, however.

Nickel Metal Hydride batteries, I'm not sure about. Does anyone know if they are handled the same as Nicads?

[Lt Swiss]

And they recommend soaking trashed batteries in saltwater for several days to neutralize them before throwing them in the garbage. They catch fire very easy otherwise.

[bearcat]

I have a bad lipo battery. It grounded my Easystar today. But it's a brand new battery that I bought a month ago at Hobby Proz, and those things aren't real cheap.

So what the heck happened? I flew a couple weeks ago, I don't remember exactly what weekend, but it was the one and only flight on the new 2200 mah battery. It still had a lot of charge left.

I think it's my fault. I forgot to unplug the battery. Over time, I think it discharged too far. Today, I discovered the battery still plugged into the ESC. That's what my battery problem was today. At home I checked it and it only had 1 volt on it. The battery charger wouldn't charge it set on 2 cells, but charged it just fine on 1 cell up to 4.2 volts. That means one of my two cells is bad.

I killed my lipo, didn't I? Damn.

Check this out:

[bearcat]

Mark, is your Easy Star's battery okay? If it's a Lipo, then when your son took it way up high until it was completely discharged, it could have destroyed the battery.

I know because I completely destroyed my brand new Lipo 2100 mah battery. But I couldn't understand how. So today I talked at length to this knowledgeable guy at Hobby Proz.

Actually, the planes that fly with their motors constantly on (the non-sailplanes) are actually a lot easier on their Lipo batteries than a sailplane is. And here's the reason.
Just by their nature, sailplanes are rougher on Lipos because they have their motors shut off frequently to glide around. By doing this, the Lipo never has a chance to continuously discharge, and the voltage recovers. So although it'll ACT okay while it's on a long gliding flight with a number of power-ups and climbs to altitude, it is a lot easier to overdischarge the battery. It may act okay because of the phenomenon of voltage recovery after letting the battery rest...even if it's taken down to dangerously low levels.

It's just like a car battery that won't start the starter motor and just click-click-clicks. You let it rest awhile and some voltage recovers, maybe just enough to turn the engine over a few times. Same phenomenon with an RC plane battery.
But whereas the Nicad and NiMH types will not be destroyed by fully discharging them, (in fact, that is preferred with those), the Lipo WILL be destroyed by a full discharge.

So a month ago, when I had that long flight with Mitch, I probably flew a good 30 minutes, with probably half a dozen startups and climb-outs. According to Hobby Proz, that Lipo was probably only good for about a single climb out, as two 1-minute "burns" would have used about 2 amps, which takes a 2100 mah battery down near zero...and I did what, 5 or 6???
THAT'S what killed my battery. It was my own fault.

I'm going to have to either be a lot more careful with my sailplane Lipos, or get MUCH larger capacity Lipos. In fact, last weekend when I didn't have the power to climb very high, that was a sign that I had already overtaxed my other Lipo battery. It came back, however...I got lucky.

Short flights are the name of the game with motorized Lipo sailplanes. Take it up once, search for thermals, and then land the darn thing.
Folks, that's not what we have been doing.