That unit is a trickle charger with only 1.5A capability with an automatic shutoff. That unit should not hurt a battery because of the low current capability, and the feature of shutting down when the battery is charged, but it will not help you much if you are living in your coach and drawn the normal current required for 12V systems in the RV to work. Your battery will drain much faster than you can replenish the charge with that charger.
1.5A is only18,75W @ 12,5V. Even less than most normal light bulbs consume.