Does a slightly bulging battery mean it's bad?

[trwalp]

I pulled my Phantom 2 Vision from the closet after leaving it unused for over a year. The battery was in the craft. I removed the battery and noticed that its gray side walls (long rectangles containing warning text) are slightly puffed out, to the point of extending about a millimeter beyond the white plastic outer body. They're a little springy, too.

It's been so long since I saw the battery that I no longer recall if this is its normal condition.

I pressed the battery test button and all 4 green LEDs light.

Is it safe to use?

 

[With The Birds]

It's less than ideal at best. I have continued to fly several slightly puffed lipo's in some models however I kept a close eye on internal resistance, mah put in and voltage balance.

For the cost of a pack I wouldn't risk it.

My guess is I went into storage full and/or discharged to critical level while in storage. Two bad conditions for longevity and performance.

 

[trwalp]

Thank you, "With The Birds," for replying. I've ordered a new pack. Is there a way for a moron to measure internal resistance and voltage balance?

Is worst case: it will explode into flames?

 

[Mark The Droner]

You can check those things with Phantom Assistant.

The general rule is, you should never use a LIPO that's swollen.

But some people will stretch that rule if the swelling is only slight.

If the battery sides are swelling past the white plastic case of the battery, that sounds like more than just a slight swelling. That means it's going to be hard to shove into the bird, and even harder to get out because it will swell more as it heats up in flight. I've never used a battery that swollen.

Yes, it could blow up. Not likely but there is the risk. It could blow up in flight or it could blow up in your closet. I would put it in a LIPO bag and then put that somewhere safe. MHO.

Next time, don't put your battery away fully charged. I like to keep mine just above 50%.