I think I just had a Lipo die

[uneverno]

Hi all,
I have a TP 1300MaH 3cell Lipo that I've had for a year or so, but only just used for the first time this week. It's way too small for my T-rex, but I was using it to set up the ESC and Gyro. I throttled the heli up a couple times w/o blades to get an idea of what the tail was going to do. Three or so tests of less than 30sec each, and all of a sudden the power just gave out. I thought perhaps the cut on the ESC had kicked in, but it behaved like a hard cut, and I've got an initial soft cut built in.

I hooked the pack up to my balance charger and got an error message with one of the cells not lighting the led on the balancer. Checked the voltage and it was 8.4 - about in line for 2 operational cells...

I'm a bit new to LiPo's, but it seems to me that a cell died. My presumption at this point is that the pack is junk now. No big deal, as I have no real use for it anymore, but I'm curious if anyone else has experienced something similar and could give an indication of the cause.

[hawkman]

I have, check the wires where they are soldered into the pack...You might have to remove some covering.

I had a fly about and the heli just kept bogging down...I put it on charge and it showed an error right away...but whats puzzling me is another pack...this showed no error after a failure...but sure enough a wire had come off. Both packs were budget type...I wont be buying them again.

The wires I mentioned were both ones for the charge and balance plug...I use a LIPO4 charger that uses the main leads...so one pack is still used...I ripped the remaining small wires out.

Trex is currently grounded till I get a 2.4 ghz set.

Rob

[uneverno]

Hey Rob,
thanks.

That pretty much confirms what I was thinking: Internal loose wire/cold joint. Every once in a while, when I hook the pack up to the balancer, all 3 cells show up, but when I try to charge it, I get an immediate error. Thunder Powers are theoretically good packs, but everyone has an off day...

I'm thinking it's not worth the trouble to open it up though. Firstly, that kinda scares me, and secondly, it's not a pack I can use for flight anyway, so why risk it. It's from a retired heli, so it's become a test pack, and I have more. I'm thinking the $ 55.00 it cost me isn't worth the potential hazard.

[park]

I flew a 7.4v pack last night for 7 min. and it did great, the heli was just starting to loose power. But when I removed the battery and it was "puffed" like air was in it? I wonder if it's gone bad?

[uneverno]

That's not good. It's a sign that the pack overheated.

Personally, that's a pack I would definitely toss. I've heard that you may be able to bring a pack back from that, but it's a risky proposition at best, and it will likely never be the same if it does work.

[park]

Yeah, it's giving me the creaps, think I'll get rid of it.

[hawkman]

You want to be very careful of a pack like that, if it goes really bad you could end up with a fire.

To get rid of the battery I would dump it in a bucket of water and leave it a while...this will discharge it. Not sure about the refuse side of things...you might want to check that out. I dont think LiPo is too much of a problem...NiCads are a problem for sure I know that.

[uneverno]

Make sure it's SALT water. Lithium and water are not a good mix.

http://radiocontrol.wikia.com/wiki/L...#Safe_disposal

Lipo is not a probelm to dispose of in the regular trash after that (though personally, I'd recycle). It's the heavy metals in other types of batteries that are a major problem. Please never throw those away - always recycle.