on my portable solar panel i have a plasmatronics PR1210 12V 10A regulator that sits inside the junction box on the back of the solar panel $60/$70 from memory
i also have a solar panel fitted to my defender with the rugular mounted inside the cubby box, it has little leds that tells you what is happening in the circuit.....al fun to look at for the first couple of days however i have not looked at it in two years now, i can get the make and model if you like
stick to the small match box size regulators and get yourself a cheap current tong/multimeter thingy
i get most of my gear through springers low voltage, good advise, close by but i probably pay a few extra dollars

