Bulging Lipos

[Storapa]

Hi all,

I've just received some cells from Hobbyking. Two identical 5.2Ah packs.

One is rectangular, the other is bulging a fair bit. Is this normal?

Also attached is a readout from each pack. The bulging pack is the one with the higher voltage.

Cheers,

Storapa

 

[Storapa]

Just measured across the cells. One is 43mm across as advertised. The other is 50mm

 

[Gringo]

Bulging cells = soon to be dead cells.

I've been using RC lipos for years and when they puff up its a sign there on there last legs, chemically breaking down.
Caused by either to high a discharge rate or physical damage.
I'd send pictures to Hobbyking ASAP requesting a replacement and asking for return postage details.

 

[Deleted member 4366]

Bulging is not good. There's nothing in those voltages that says anthing is wrong. It looks like just the cell under the label is bulging. Can you feel gas in it?

I'd get straight onto Hobbyking and show them the photo. Don't attempt to charge it, which could be dangerous.

 

[Storapa]

Thanks for your replies.

Have sent photos to Hobbyking. We will see what they say.

I can't feel anything / gas. I think the bulging cell might be living outside tonight.

 

[mfj197]

Thanks for your replies.

Have sent photos to Hobbyking. We will see what they say.

I can't feel anything / gas. I think the bulging cell might be living outside tonight.

Sensible. Might also be worth putting it in an empty incinerator or other such receptacle in case it goes off. I've a flameproof envelope for charging lipos which can resist a lipo explosion in the worst case scenario.

Michael

 

[Storapa]

I've sent further photos to Hobbyking. Hopefully they will sort this out as quickly as possible. I'm eager to get on with building my bike.

I think I might be buying a flameproof envelope now. I'll also charge outside in a steel box in future.

 

[Deleted member 4366]

I don't think you have to panic about them. They won't blow up in the middle of the night. If lipos swelled up and caught fire by themselves, Hobbyking's warehouse would have burnt down long ago. It's best not to charge them.

If you're lucky, they'll send you a new pack. You can then convert the pack to a 5S one by removing the offending cell. With lipos, you can have any configuration you want. At 11S, a 48v controller will switch off at about 3.6v per cell, which is pretty close to empty. The only drawback is that you lose 10% of your speed and power.

 

[Storapa]

Hi d8veh.

Good point about the Hobbyking warehouse. I feel a bit more relaxed about them now.

More photos sent to Hobbyking with batch code and bar code.

They are getting their product specialists to look into it.

 

[Storapa]

Full marks to Hobbyking.

I received a full refund for the battery.

I have just disassembled the pack. I'll post up photos in the morning.

Cell 5 (of 6) was heavily swollen.