Another Bad Turnigy Lipo??
 

I bought a pr of 1600mah 20C 3S Turnigy lipos to run in a mini. One of them shows 8.42v by DVM across the main power leads and the GT Power voltage analyzer I bought shows 3.9v, 3.91v and 0.26v or full voltage of 8.07v.

Can this be a dead cell without it being puffed? It looks perfectly normal, just like the other 3S that reads 11.61v. Why is there a diff in what I read across the main power leads with my dvm and what this GT Power voltage analyzer is seeing off the balance connection? I have a charger that charges thru the balance wires and it sees only 2 cells, it does not see the other and will not apply any charge to the prob cell.

Am I looking at some kind of internal problem that I might be able to fix? Thanks

You can check the balance wires and measure each cell using a voltmeter. But, your symptoms sound exactly like what I had on two of my packs, except in my case, the errant cell was only ~0.5v lower than the rest. Even when I charged that individual cell by itself, it would still drop over time. Bad cell.

Thats what I've done and having a hard time believing - 3.9, 3.91 and 0.26v??

I thought if I had a cell that low for real, it would be as big as a balloon.

Cells do not have to puff, they can slowly lose voltage and not puff. You can try a very slow charge on that cell using the balance wires. You may have to use a nimh setting, then swap over to a lipo setting when the voltage goes over 3v. Do not use more than .10amp and do not leave it unattended during the nimh charge. I have revived a few low voltage cells this way, but what Brian says about the cell not being as good as the others may well be true.

Yeah, had it happen to two Turnigy packs. One cell just wouldn't hold a charge. I would get it to be the same (if not slightly over) the other cells, let it sit for a few days, and when I checked it again, it would have dropped back down.

Hope it works out for you. Maybe you'll get lucky and it'll just be a pack assembled with cells of mismatched charge level.

Thats what its looking like right now, I charged it as a NiMh to get the voltage up over 9v and then let it charge as a lipo. The cell that was way down is still off - I stopped the charge when the otehr 2 cells reached 4.2 and the weak ones at 3.79v, but the voltage has been steady for several hrs. I'm going to put it on a balancer and let it even out and then top it off.

I've read about others like this, just was thrown with this one being so out voltage wise. Will get to run it several times tomorrow, its finally gotten a little dry here! That will tell what kind of lipo its going to be.

Thanks guys!