Solar Power Maintainers

the word you're looking for is solar automative battery charger. do a google search on that

https://www.bestreviews.guide/solar-car-battery-chargers?&origin=google&google_params%5Bmatchtype%5D=&google_params%5Bnetwork%5D=g&google_params%5Bdevice%5D=t&google_params%5Bcreative%5D=533109193145&google_params%5Bkeyword%5D=&google_params%5Badposition%5D=&google_params%5Badgroupid%5D=125102079255&google_params%5Bcampaignid%5D=13872118049&bs=&google_params%5Bfeeditemid%5D=&google_params%5Btargetid%5D=dsa-19959388920&google_params%5Bloc_interest_ms%5D=&google_params%5Bloc_physical_ms%5D=9021554&google_params%5Bdevicemodel%5D=&google_params%5Btarget%5D=&dest=0&sys_id=0%7C903&origin=google&google_params%5Bmatchtype%5D=&google_params%5Bnetwork%5D=g&google_params%5Bdevice%5D=t&google_params%5Bcreative%5D=533109193145&google_params%5Bkeyword%5D=&google_params%5Badposition%5D=&google_params%5Badgroupid%5D=125102079255&google_params%5Bcampaignid%5D=13872118049&bs=&google_params%5Bfeeditemid%5D=&google_params%5Btargetid%5D=dsa-19959388920&google_params%5Bloc_interest_ms%5D=&google_params%5Bloc_physical_ms%5D=9021554&google_params%5Bdevicemodel%5D=&google_params%5Btarget%5D=&new_api=true&dest=0&sys_id=0%7C903&gclid=Cj0KCQjw1_SkBhDwARIsANbGpFu2PTpSR60tFt9lNhzyKpnKFQgxJzB2kIMwIAVMThbWJGQBKHv8EJgaAqRMEALw_wcB

I have had a 80 watt panel on the side of my carport for 21 yrs and it is wired to the controller inside the mh, keeps all batteries charged.

My system had 875 amp-hours of battery bank. I keep it charged between trips with 256 watts of solar.

https://freecampsites.net/adding-solar/

I use a 20 watt solar panel to keep the battery in my trailer charged. It does a good job.

After reviewing the original post, I realized I saw no reference toLithium batteries. So the following mostly only applies IF you have Lithium. Solar Controllers are selectable for battery types and will perform the maintenance function with a float charge.

A lithium battery rated battery charger with have a float charge mode as do solar controllers. Extra lengths of premade cable with solar connectors can be had on Amazon.
Forget using the search term maintainer.
The charger or the battery BMS MUST have low temperature protection to prevent trying to charge below freezing, very bad for LiFePO4. While it can be used below freezing, mine came with a manual that states it should also be stored at above 14* F.
Let’s regroup. LiFePO4 retain their charges longer and have a slower storage discharge rate. Part of the reason to use Battery Maintainers in storage is to help prevent liquids freezing, Lithium, NO liquids. I.e, battery MAINTAINERS are not needed for Lithium, just chargers.
Fully charge your battery for storage and disconnect it. Then either leave it in place or bring it in the house to keep it warm and cozy. Bonus, less than half the weight of LA batteries and NO dangerous outgassing while using or charging inside.
The solar panel and controller/charger on the shed roof is a good idea to keep the battery fully charged and ready to go camping. Especially because you’ll be using the battery power when accessing the trailer in the shed.