When we first got the camper I was confused by the low charge rate of the solar charger. In bulk it would charge just fine, but when in float — it would let the battery discharge to ~13V before re-entering bulk charging. That is far too low for a camper solar setup.
I found an online discussion regarding the EPEVER Tracer that explained the behavior. The settings are not well optimized for a solar system on a camper, where you want to utilize the sun as much as possible.