I'd recommend looking at the Duracell AA 2650mAh batteries.
I have not seen anything higher than these on the market yet.
If the mAh is not listed, then I wouldnt buy it.
This number is directly related to the amount of time the batteries will last during use.
I used this setup for many seasons. I have now gone to a single 12volt (think fire alarm or emergency light size.) battery.
The draw back I found to the AA system is that when you have a single battery in the mix fail, the others are unable to carry the load; and unless you have a way of checking the batteries, you dont know which ONE to replace.
I opted for the single battery setup (albeit in a small version 3 Ah) so I knew which battery had failed.
Here is a link the my club forum site that has some pictures of my battery setup and install.
It has other pics as well, but your interest may be of the battery rigging.https://www.gulfcoastkayakfishing.com/f ... 19&start=1
Don't lead me to temptation, I already know the way.