Battery maintainers/trickle chargers? (12v and others)

I’d like to have a few more 12v batteries on trickle chargers/maintainers around home, maybe with solar panels, and that kind of gear seem to be changing fairly fast.

My memory and intuition are outdated on this sort of thing.

Curious if anyone knows a current informed source on what’s what.

I’m in an earthquake area so keeping some spare AGM 12v cells charged, even when they’re too old to be trusted in a vehicle, gives me a bit of extra power backup.

I know about the 110v Deltek “Battery Tender” models and have one in use on an old flooded battery. I see they have a model now specific for no-fill AGM batteries.

I have a couple of small solar panels with charge controllers in use.

Deltek has new models just about to be for sale, in California and Oregon (state/utility stability/efficiency requirements forced upgrading their design)
They have several different solar panels with built in battery maintainer gear.

And what else is out there? There are a few other brands.

There are some dirt cheap mystery 12V battery chargers from DX, you know how to find those, not linking ’cause I have no idea what they might actually be selling.

——That’s for 12V but I have the same question for other kinds of batteries — looking for pointers/ ideas on a solar charger that will trickle/maintain but not cook batteries left hooked up indefinitely, as part of the emergency preparation.

so as usual, opinions are fine, but, since I mistrust my own, I’d welcome pointers to actual reviews/ takeaparts /tests.

I just got a CTEK MUS 4.3. Nothing fancy. It'll be kept on my car all the time, and plugged in while parked for more than a couple days. I'll get one for the motorcycle too. I don't know much about solar, but moving into a house with solar, so I'll be learning a lot about it if I want to add a few more panels and energy storage.