Shorted Cell
 

I direct shorted a zippy 5000mah 4s pack....nice spark. There is no puffing and or fire!. Now when connected to the Hyperion is shows number 3 cell as zero volts the other cells are fully charges. There is no output voltage at the battery plug. Why is there zero volts at one cell and no volts at the output. I would think the bad cell would show something. Did a solder joint blow off?

I am nervous about taking them aprt to look...could easily short them again.

Any ideas?

Well, sounds like you killed the cell, but the solder joint may have come off. Usually it takes quite a bit to get the cells apart, so it is probably a dead cell. If you want send it to me and I will take it apart and let you know what is wrong. Check my sig for more lipo info if you like.

I believe some Lipo's have a "fuse" inside them. Rather than exploding in a ball of fire in a dead short situation, this weaker conductive run will blow.

I shorted a 5000mah 2S pack one time with the same result. It pushes ALOT of power before it lets go though.

Can it be fixed?

If one cell is dead the pack can be disassembled and made into a 3s pack...

Not much chance reviving a cell that is at 0v. Plus the cell is not completing the series curcuit of the pack, so it is most likely gone.

I'm inclined to agree with this.I have to wonder whether zippy uses the same thin tabs on their cells as I have seen on other budget lipos.In which case I would think you could melt a tab off the cell,duplicating your results,and the cell could possibly still be good.But there's only 2 ways to tell,split that sucker open,or send it to someone who will.

I split it open but do not see any collateral damage. I am afraid to hit it with a soldering iron for fear it will blow...(shorting it out).is this a rational fear? There is a "connecting plate" on the end of the cells with the wires and everything looks good. I have tested in numerous places with a volt meterand cannnot get a voltage reading anywhere but when hooked up to the hyperion 3 of the 4 cells read a voltage with one cell zero.