Heat and Batteries - Why she no go?

This may be a simple one, I'm not sure. I think I may have cooked my battery because of what happened to me today (wall-o-text ahoy!):

I've been out of town a couple of weeks so the bike has not been ridden in something like 20 days. It hasn't been on a tender during this time. Before bed last night I decided to ride today and went to see if it would start like it should. Nope. Dead battery - no big deal, slap the charger on it and we'll be good to go. So this morning I go out to the garage and try to fire her up - no dice, acts like the battery is weak. I hooked the charger up to the battery and was able to start with the boost that provided just fine. Rode to work, no problem; rode to lunch, no problem; rode home, problem. I was almost home, been riding for about 30 - 40 minutes, coasting to a stop to make a left turn. Radiator fan was on, blinker was on...bike shuts off. Indicator lights are still on, but I pull and check all the fuses anyway. Nothing blew...weird. :crazy: So I backed up and roll-started it (first time ever doing that), was successful on my second attempt. Fine, ride home - it's about 2 miles from here. I get to the corner of my street and it dies at the stop sign again. Fortunately my friend lives on the corner and I was able to push it over there to get a jump and ride it the last 3/4 of a mile home. When I got home I let it sit idling to see what would happen. After about 10 minutes it bogged down and died.​

TL;DR - bike electrically died twice on my way home today while coming to a stop. No fuses blown. Wat do?

Post-mortem analysis revealed a possible lack of heat shield over the exhaust directly beneath the battery [Picture 1], the filling ports of the battery slightly raised [Picture 2], and a dry interior of the battery [picture 3]. After the bike had been sitting dead for another 10 minutes, I took a temperature reading on the positive post of the battery - appx. 130° f. The battery is an Absorbed Glass Mat type purchased from Wal-Mart a little less than a year ago. It's not supposed to require adding water, but it looks awfully crusty in there.

Your thoughts, gentlemen?

Picture 1 - Potentially Missing Heat Shield
There is a screw boss on the exhaust, visible in the middle of the shadowed area.


Picture 2 - Battery Fill Port Cover Bowed Out


Picture 3 - Battery Interior
​

 

I would check the rectifier (do a search) and if it is functioning within tolerance put a high quality yausa in there. You can wrap it with heat tape if you want but I think you may find your r/r cooked the battery (which was a cheapie) and things cascaded downwards from there