Any Electrical Wizards Out There?

A four year old battery as you suspect in your first post should be replaced. We do not buy batteries, we seem to just rent them. I would not buy an optima. Go to Walmart and buy the biggest deep cycle battery that will fit the hole. Clean the cables and where they attach to. By cleaning I mean remove one at a time and clean them with sandpaper or wire brush. Clean and shiny is an absolute must at 12 volts. Twelve volts has little "push or pressure" and will not go through much resistance. This can cause slow charging and low voltage at the devices you are running. My 89 Class C only charged at 3 amps. That drove me crazy. I used a ten amp car charger at that time to help and often ran the big engine to get it up quicker. In addition I added a second battery. Installing a sealed battery under the sink and running a pencil size wire really helped. Eventually I did add some solar. You will be much happier with a newer charger and a fresh battery. Changing bulbs to LED's will help a bunch as well. You can buy them cheap on E-Bay versus many other places.