Can I use the solar to maintain the battery during storage?
The 200 watt panel is going to produce 16 amps. What you don't want to do is overcharge the batteries when not in use. Your solar panel could potentially overcharge the batteries and that can kill a battery in short order. On my equipment that isn't used on a regular basis I use battery tenders, they will keep the batteries fully charged, but not overcharge them. Now if you don't have an AC source where you are storing your rig, the battery tenders obviously won't work.