Battery Trickle Chargers
Let me add my 2 cents from the Phoenix side.....
Battery life in this environment is 2 years.... No matter what type of standard battery you have. The typical failure mode is a swelling of the case and a cell going dead. Battery voltage ends up at about 10.5 in the failed mode and the internal resistance of the cell is so high that it limits the cranking current to spin the engine.
This is the result of several contributing factors... the worst are:
1) The weather never gets cold enough here to properly exercise the battery and it tends to have a "shallow" charge that does not use all of the plate surfaces.
2) Underhood temps (I'M sure the rear mounted is only slightly better) are high enough to cause battery overheating during the charge cycle and thus plate warpage.
I know this doesn't have much to do with trickle charging, but here is my connection..... In hot weather climates... If you maintain a trickle charge on the battery without exercising it regularly it can create a surface "float" charge that has little depth for serious cranking. My recommendation is that you use an "automatic" charger of a conventional type that will put as much as 10 amps into the battery and then taper off to a trickle when fully charged. Sears sells a nice one. Put this charger on a pool timer or any type of timer that will handle the watts required. Home Depot has some that will work too. Let it charge for only one hour a day. This will provide some exercise for the battery and still maintain a full charge.
If you ask the guys in the cart barn at your local golf course, you will find out that they hit the batteries with a hard charge every night and they love it. Yes, they are deep cycle batteries, but the theory is still valid. They have 30 amp chargers on a huge timer.
Bottom line..... There is usually more than one way to solve almost any problem.....
Best of Luck,
MIke