John,
It's like its owner, dirty.
The Lipo is a LRP 4600 30C. These are not cheap. I got one to try and have been happy with it, although the IP3800 is very popular and will be the next batteries I get for mini.
I don't balance my packs and I don't touch them after racing. Just leave them until the next week and top up when i get to the track.
My batteries get a workout as I practice normally once a week and race twice a week when I'm home. Other than that they get left for periods of up to a month were they stay in the Lipo sack.
I have only had problems with swelling packs in Touring Car and the old 4000 IP Lipo packs. I must add that I thoroughly abused those packs and still have a couple I use for practice. These I would run to cutoff, which I had set at 3.8 volts per cell. This certainly hurts the batteries as they do not last as long. They are soon destined for greenier pastures.
BTW,
I have cleaned the car, ready for tomorrow night, providing the rain disappears and the sun comes out.
Later,
Calvin.