I have this unit wired to 45 watts of solar panels. I use this system to keep six deep cycle batteries charged on 2 RVs that get used every 4-6 weeks. Every time I have used the RV the batteries were about 12.8 volts. During a weekend usage I rarely have to start a generator unless I need the A/C or microwave. Whatever I use during the night (heater blower or a cooling fan) the panel recharge thoughout the day. I put a similar system on a friend\'s RV and his batteries are usually 14 volts. Great to have confidence that when you get to the camp you\'ll have fully chargerd batteries. Maintenance free at that!!