I own a large amount of equipment, and some of it, such as my home generator, is supported by battery maintainers.
Overall, reliability of those has been pitiful. They are sold by "features", "microprocessors", "smart charge modes", have numerous LED status lights, etc.
The reality is that most of them fail in a year, often in moderately cold weather or for no reason at all. Some stop working, some display blinking lights and do not do their job, some drain batteries when they fail etc.
I am personally not even asking for much, just a weatherproof device that keeps the battery mostly charged and not overcharged. Unfortunately, I have not been able to locate anything useful that could survive being out in the weather.
The one item that I had a lot of success with, is a solar battery charger that I use on my rough terrain crane, that one seems to be a champ and the crane is always charged. But the 110v devices are abysmal.
Would anyone recommend some weatherproof charger, the "dumber" and less sophisticated, the better. Thanks