with a single 100w solar panel, it might not even NEED any controller, though if it has one, it's probably right with the House Batteries, which it is attached to in order to charge them.
a single 100w panel is not going to go far in 'charging' the batteries, even with full sun - but it will help just a 'tiny' bit - just don't 'over expect' - it's not going to 'run' anything in the RV, either, it's only to help 'trickle charge' the batteries.
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