Inflated battery!!

[aw]

I purchased one of these 2500mAh LiPo batteries for my MightyHat about 5 months ago:

http://www.ebay.com/itm/162171810914

The battery is a pretty tight fit between the rpi and mightyhat board already, but the other day I noticed it was busting at the seams.  The battery had inflated and I'm lucky it didn't get punctured by solder joints on the bottom of the mightyhat board or the heatsink on the rpi.  It feels like like the inflation is entirely gas within the battery, the solid parts feel normal.  Did I get unlucky with this battery?  Should I consider this battery bad even though it still holds a charge (ie. should I perhaps deflate it and seal it back up)?  Any leads on batteries that I could actually trust?  Thanks

[WhiteHare]

Definitely don't use it. 

This is one of the reasons why I've been focused on using supercaps rather than Lipo's.

I guess this also proves that just having the overchrage/undercharge/short-circuit, etc. circuitry isn't enough.  You need other protections, like a pressure sensor and/or temperature sensor(s) to also help protect against disaster.

Did you exceed the recommended  limits for charge rate?  If it's that critical, they should have hardware protections for that as well, but it doesn't sound as though they do.

[ChemE]

Darn, and I thought I was going to find a new spin on the Zn/Air batteries when I opened this thread!  Speaking of supercaps, that company has not gotten back to me regarding the MEC202 vaporware solid state battery.

[aw]

What are the charging characteristics of the MightyHat?  Could I perhaps use a more stable(?) Lithium Ion (18650) instead of these LiPo packs?  Google tells me that LiPo is 3.7v nominal, 4.2v max while some Lithium Ion are 3.6v nominal, 4.1v max, but others might be identical to LiPo and therefore compatible with their charge circuits.  Does MightyHat have any bridges to cut or solder that'd make it work, might it work already, or do I need to hunt for these higher spec'd Li-Ion batteries?

[Felix]

@aw,

Those types of batteries can be quite unreliable. Made in ... guess where. Certified or anything? Of course not.
I suggest buying cell phone batteries. Those are very high quality and have certifications. I've had one in my attic with a weather shield for the past 2 years, never thouched it, it was an old discarded battery from a mobile phone that could not hold a charge for more than a few hours - i recharged it to whatever it could hold and put it up there to see how it works and still going after 2 years with a Moteino and weatherShield.

The attic can reach 130F in a hurry in the summer and endure way below freezing temps in the winter - so I would be very hesitant to put a chinese LiPo in such "extreme" conditions -

The MightyHat charges at 212mA by default, you can change it to 500mA via a solder jumper on the bottom. Both would be no harm to a 2.5Ah battery like you have.
Can we see a photo of your battery? Would be lovely for the "from china with love" section of my blog

[aw]

Cell phone batteries seem to be just as much of a grey market as the generics, is the certification real?  Is the branding real?  Is it used or "seller refurbished?  Cell vendors can't escape this problem either... Samsung.  Chances are they're made in the same place.

[Felix]

Possibly but usually the fakes have some telling signs they are fake especially if you put them side by side with a known genuine.
Sometimes the genuines have hologram stickers with branding and very high quality print, which I doubt the fakers go through the trouble of investing in that and high quality packaging, when they can just generic package.