I can't answer your question about a solar charger but I think that before you try using a solar charging system that you should fix the problem with the disconnect.
First off you need to find the disconnect relay and toggle it(turn it on and off). If there isn't any click when you turn it on, you have found the problem and you need to determine if the switch is working. Use a trouble light, buzzer or DMM to see if turning on the switch sends power to the relay coil. If there is power to the coil and still no click, you most likely have found the problem.
If you are familiar with electrical trouble shooting to done all this, go ahead and replace the relay, if you're nervous about doing more either ask for additional help or get a mechanic to replace it for you.
Once you have the relay working, look into solar charging.
There is a ton of information here in the forums and on line sites like youtube where you can learn how to repair a lot of simple things, things like a disconnect relay. There are also quite a few members of these forums that will more than willing to help. Don't be concerned about criticism, some guys are a little abrupt but really want to help, just ask.