Solar Boombox Upgrade
Ok so im looking to upgrade my DIY portable boombox for the 2nd time and one of the things i want to add is a solar panel to supplement the battery power from my 12v 7ah sla battery, that by itself will currently run the thing for about 3hrs at full blast. The new version will have Directed CSX-650 component speakers: (bottom of this page) http://www.lightav.com/car/directedaudio/directedspeakers.html and the amp will be one of these: http://shop.41hz.com/shop/item.asp?catid=42&itemid=43 , so what id like to know is what tech spec should i be looking for in a solar panel that would be capable of charging the battery while the boombox is not in use and will supplement the battery power to extend the run time while it is in use? Also will i need some kind of circuit/component to prevent overcharge of the battery?
Oh and is there some kind of simple light/gauge i can wire in to show the charge level of the battery?