The simple direct answer is you must start from scratch. Nothing about the 10w panel is upgradable or usable.
It is mostly a worthless marketing gimmick. Oh, it's trickle charges 1/2 an amp to your batteries sometimes. But that's all.
You can't use the wiring from it. And there is no charge controller. It's wired directly to your batteries and if it were not so useless at making power it would have destroyed them without a charge controller.
1 Solar Panels
2. Wiring from the roof to the area near your batteries probably 10g or 8ga
3. A solar Charge controller - a 30amp is a good place to start
4. Fuses and wiring to connect the controller to your batteries
Just proceed as if you had nothing already, because, in actuality you do not.
That starter kit link you posted would work - but there's no wiring with that. You'd need to figure out placement and a way to run the wires from the roof to the charge controller and then from that to the batteries.
Originally Posted by jrt13
I don't need anything crazy, just wanted something to power my incidentals without killing my battery.
One more thing - you don't really power anything with your solar panels. It's your batteries that do that. All solar panels do is replenish the power that you use up from your batteries. Solar panels are simply a method to charge batteries, not really run appliances, etc.