On Nov 10, 2017, Ignoramus30995 wrote
(in ):

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

What you want does exist in the marine world. When boats are in storage (on a
cradle in a boatyard or back years), people often use trickle chargers to
keep the batires charged (and thus freeze-proof). These chargers are almost
always used outdoors, and are powered by 115 Vac.

Ask around your local boatyards for the best brands. And for the
avoid-at-all-costs brands.

Joe Gwinn