Yep... hot weather is a primary failure accelerator on batteries... followed closely by being in a persistent undercharged state (ie: below 40% of saturation charge).Maybe this explains it:
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1) The amount of charge at full charge actually declines with temperature in flooded cell batteries.
2) Hot weather tends to cause evaporation of the electrolyte as well... and so the cell electrolyte in each cell needs to be monitored periodically, and topped off with a little distilled water if the levels are low.
3) Hot weather tends to also sulfate the plates a bit faster as well, and plate sulfation is slow persistent killer of all batteries.
All of the above becomes a real problem for the infrequent or short trip driver... since the battery will often not be fully recharged after a drive.
And NO... a bigger battery will not change any of the above. People keep pressing this theory but it is simply not factual, and goes to a misunderstanding of how flooded cell batteries actually work. All a bigger battery does for you is give you another 20-30% of reserve charge (good for about 10 extra days on a gen5 CRV before the battery is dead, and the extra CCA you get from a bigger battery is wasted on a CRV engine. Better to just put a higher quality 51R in that gives you more reserve capacity charge in the same footprint.
An AGM battery will address some of the issues with heat better. , but they too have their own idiosyncrasies to deal with as well... so you need to know what you are buying and what you are not. In my view.. AGMs do not provide enough benefit for the additional cost required. Better investment to simply buy a premium 51R which will have better specifications than the stock OEMs, and most after market 51Rs.
Of course there is a school of thought that just ignores the battery, then complains when it dies before it's expected life span too.