Originally Posted By: kc8adu
for that usage the battery is not that important.
the charger is.
a regular car battery as big as you can fit in the box will do.
a truck battery like a d31 will do a bit better.
each gate cycle is a lot like starting a car.
only a small % is used.and a d31 is known as a high cycle.
a hybrid between a sli and a deep cycle.
the charger must be able to top up the battery in a reasonable time to prevent sulphation and must not overcharge long term.
upgrading the charger will help a lot but your battery will age out before it wears out.
a bigger battery will hold up the system longer and give more operations during a long term power failure.
A quick D31 google revealed a ~$289 price tag at Oreillys.
I am just sticking with a marine battery because that is what the installer used 15 years ago. Perhaps a better (newer) charger is in order.