100w would give you more leeway and not cost too much more so this would be the best bet.
Solar panel and battery for small utility trailer.
I recommend the solar power kit from torklift tla7713.
4 25w solar panels 6 panel connection braces 2 led bulbs 1 dc connector cable 1 battery clamp connection cable 1 10a charge controller 1 4 in 1 connection cable amperage amps 6 8 material aluminum frame plastic product height 7 8 in.
The l 16 size battery i used for the solar power trailer shown in these photos has a 7 x 12 base x 17 height and weighs 128 pounds.
Product width 13 5 8 in.
Use this kit for rvs boats 12 volt battery charging or charging small electronic devices.
Best travel trailer battery.
Depending on the sunshine you re expecting and energy use you should be able to keep this charged for a weekend off just a 50 100w solar panel.
3 piece grape solar gs star 100w 100 watt polycrystalline solar panels a 40 amp grape solar comet charge controller cables and manual.
Product length 39 in.
Product weight 33 40 lb.
A solar panel would work well for you with this application.
Unless your trailer has dual axles it is doubtful you will be able to use more than eight of these l 16 size batteries without serious weight distribution problems.
To add solar panels to the battery charging system on your trailer i recommend looking into the redarc in vehicle bcdc battery charger 331 bcdc1225d this will allow you to use both solar and battery power to charge and maintain your auxiliary battery.
You would also need a power control panel to charge the battery.