Bob,
Your battery needs a good charging with a shore power charger. If you are 
lucky, that might bring it back to life. Sounds like you are using more power 
than your solar panel can place back into the battery.
You either need a shore charger or possibly a second battery and place both 
on a charge/discharge regulator from WM. I had the same problems a few years 
back and a hail storm took out my solar panel making my decision an easy one, I 
went with a "Guest" shore charger and removed the useless solar panel. When I 
dock, I simply run an extension cord under the pop top cover and plug it in. I 
get a full charge on both batteries overnight.
I thought about using a battery selector, but then decided to seperate power 
usage. I have the stereo and the VHF on one battery, and use the other for 
lights and everything else.

Rummy