[MarkCrowe]

OK, so I got my new Thunder Power 610C up and running, used it to set the storage charge on my parkzone battery, then tried to charge my brand new turnigy battery. Same cells and maH rating; 3S, 1300 maH. I get an error message that pack voltage is too low/wrong polarity, and I can't get it to initiate a charge. Anyone else have this problem?

On the helifreaks forum it seems I'm not the only one having this issue and Thunder Power hasn't been helping anyone to date. Anyone else here run the same charger and could maybe run me through what I'm doing?

[aceplant00]

have you checked the packs voltage to ensure it is correct.

[waylander]

Yep check the charge on the pack first must be at least 9v. I've had 2 of my last 20 hk packs with at least 1 cell under 3v

[MarkCrowe]

Put a multimeter on the pack, and it's not even enough to register. Same meter, other pack, got 10.4V, which is what I set it to discharge to.

So I'm running an experiment: both chargers I have (the parkzone and the TP610C) are too 'smart' to put a charge into it. So, I've MacGuyvered a charger using the AC portion of the parkzone charger and an EC3 plug to 'force' some volts into the pack that way (and watching it VERY carefully). I'm only trying this because I can't think of any other way to get enough voltage into the pack that it will register high enough for the balancing chargers to do their thing.

Thunder Power claims the 610 has a mode for a recovery charge for badly over-discharged batteries that it's instructions are woefully inadequate for. Best solution I can come up with before I use a brand new (but cheap, at least) lipo for target practice!

[waylander]

You can use the 610C in nimh mode to charge it up to a minimum level but... over discharged batteries will perform poorly at best. I'd suggest that you never run that particular battery in series or parallel with another.

Make sure that regardless of how you do it, you keep a good eye on it, suggest you do it in the garage in a lipo sack (or other fire proof container).

[MarkCrowe]

UPDATE:

I did the unthinkable with the unintended help of a site that showed the wiring diagram of a balance connector, as I was trying to figure out exactly what was going on. I then started to suspect a physical wiring problem rather than undercharged cells as 2 cells were reading 3.8V each and absolutely 0 on the third.

So I (carefully) took the wrap off the lipo and started inspecting wiring and solder connections. Guess what? That dead cell wasn't dead; sometime after it was assembled, the thin copper strip coming from the + side of that cell had separated. A bit of careful cleanup, a quick touch with the soldering iron, and the pack was reading 11.5V. Carefully put the pack back together, re-wrapped with some 2" wide vinyl electrical tape to hold everything together nicely, and I've saved the pack which is charging as we speak.

HOWEVER: I'm glad I got the pack serviceable, but there is no way of knowing how long it will last. I did a lot of tinkering with something no one is supposed to tinker with, and that solder connection may not hold- I was careful, but there's still glue there because I didn't want to compromise the physical integrity of the cell- I do know what happens when lithium meets oxygen!

In no way do I blame HobbyKing; the cell was charged, indicating it had been put together properly; I have no idea how it was handled after that or on its way here; the copper strips used in those cells is very thin and where I found the break is in a spot fingers should never get to. I'll use it as long as it holds out; it's only for the Cub anyhow as a spare pack and it'll be treated as such. I'll charge it, discharge it and set a storage charge until I want to use it and watch carefully each and every time it's used.

So for anyone who wondered, sometimes a dud battery isn't, and sometimes they can be saved!