Lipo question
 

Last week I bought two Flightmax lipos from HK, one is just fine the other showed 1.22v in total for a 4s pack. Two of the cells were slightly puffy, now it's completely dead and the other two cells are puffed as well, only slightly but it's there. I have registered it on HK within 24 hours after receiving it, but the cost of shipping makes hardly worth the effort to send it back even though I'm within warranty. What I mean is if there is anything I can do to save it I will not spend the money on sending it back, but if you guys deem it a lost cause.....well.

sometimes you can charge a lipo in nimh mode at a very low amperage to revive an over discharged lipo. Under 3.0v/cell is over discharged.

Since each cell should be atleast 3.0v a new 4s should be 12v minimum. Your extreme low initial voltage reading is indicating 3 cells were fried when you got it, and the 1 that was hanging on died in your care.

I'm sorry to say it is a lost cause. (assuming you checked individual cell voltage at the balance tap- if the voltage at any of the balance taps is more than the whole pack voltage the problem is an internal solder failure)

Yup I checked it at the balance tabs, just after I got it two cells read 0v and the last two were .55 and .62v. Now all cells are flatlined.
Sounds like I will have to send this one back to hobby king. It's lucky for me that the first pack I decide to check is the one that is bad, and that since I ordered from the DE warehouse I will only have to ship it to germany.

Good luck. Please update this thread if you are able to sucessfully send it back and get it warrantied.

I've decided to give it a try and see if it can be saved. I have it on a nicd program at .1A charge rate monitoring it and see if I can get it to 12v. Then we'll see if it charge on a lipo program.

I have the pack sitting in a ceramic pot to contain the heat if something should happen and I will be watching it like a hawk.

No dice it drops voltage almost as fast as it takes it, and it is now puffed a little more.

What about NiMH? I've never read anyone doing that with the NiCD program, but lots have with the NiMH.

What exact LiPo's did you buy?

I ended up charging in on the nihm program, got it up to 12v quickly stopped and switched to lipo, then it would drop a little begin charging before the charger giving me a low voltage alert.

It was a 4s 30c 5000 Flightmax Zippy. The other one just like it is fine, all four cells are within .01v.

sounds bad
 

Sounds like a bad deal to me. We have to expect that doing buisness overseas can end up with a bad deal from time to time. Thats just the nature of the Lipo market in general. You have to figure that about 90% of the Lipo market probably comes from China. Dealing with chemicals is never an exact science, and once it goes bad it is gone. I would have just packed it back up and sent it back. Let them sort it out.

I'll definitely do that next time it happens, live you learn. :wink: