Sounds like you morningstar charge controller screwed up.Do you have a temp probe hooked up to it.It should have sensed a higher temp and stopped charging.
Depends on where you live the group 29's are light on cranking amps mine say 675 CCA for my generator from WM,the group 31's are around 950 CCA from Sams,the guy told me he paid around 100 bucks ea for 31's at Sam's we were replacing his group 24's with
No, on the Group 29 they are rated at 845 Marine cranking amps, but they are combination start and deep cycle batteries that is why they are heavier than the Group 31's, same size, just the posts are different. A better battery than a Group 31.
I just bought two 950 CCA (at 0 degrees F) 31's for $90 each at Truck Pro (they are in 33 states), house brand, made by Deka. (1000 CCA's are $100) Virtually all batteries are made by Exide, Johnson Controls, or Deka. The 31's from Batteries Plus have M10 studs, which don't work well with 3/8" nuts. The 31's from Exide don't have a handle, just finger grips.
The Walmart Group 29's use a combination solid post and a 5/16" threaded post. Group 31's use a 3/8" threaded post. ...
Ask for a strap they will give one free Walter,I buy post type 31's and use the military post connectors then you don't fight getting all the connections on a battery stud ,only the military would use the post type batteries with stud type cables but the connectors are neat.If the time comes when you can only get the stud type battery just remove the post terminal connector and connect the cables to the stud a 2 in 1 deal the military came up with