Swollen Lipo
 

So my RC sat for month or so, went to use it and the batt seemed dead.
Went to charge it and my Equinox said error. Then I noticed it looked like its about to pop. I do believe it was left unplugged, It was always balance charged, and has only been charged 7 times. As I put a sharpie mark on it every time I charge it.
Battery is a G Force 20c 1300 mah 3s.
Luckily their very affordable.
I would like to make sure this doesnt happen again. So where did I go wrong?

The first 6 words of your post point to the possible problem. If you drained the battery down to the cutoff then let it sit for a month, it possibly self discharged too low and swelled up and died.

Point taken.
I guess you learn best from your mistakes.

So, the all lipos needed to be charged somewhat before storing? Just to clearlify if this is a proper method or not.

Lipos should be stored at approximately 40 to 50 percent of their capacity.

So a 1300 at 3.0 volt cutoff should then be charged to about 600 milliamps for storage. And I think that's right around 3.7 volts per cell... could be off a tad on that one. Almost at nominal voltage.

Thanks for the clearification. It's what I kinda figured. Thanks man!!

the store feature on my hyperion puts the cells at 3.90 volts. there are always conflicting views for storage charge, basicly between 40-60% or 3.7 to 3.9 volts is acceptable.

if the pack was close to 3v per cell it may have self discharged bellow that and damaged the pack. on the other side, if the pack was stored fully charged that could have caused it to swell

Most likely my TX batt went dead before the RC. And I did nothing about it. Probably should of put some more charge in the 3s.