Check the link below, it's a good start to see what is needed for 12 volt charging. I own three of these kits and got them on sale just to play with them. The inverter is not needed for battery charging, but you may wish to add a battery monitor as well since the solar would continuously charge the batteries without caring if they are being overcharged.
Contents Solar panel, 7 amp charge controller, 200 watt modified sine wave inverter, wiring accessories, green LED test light
Moving up to 24 volt though, this kit seems appropriate for your use.
This kit is $1300, and has everything you need except for the monitor.
Check out Youtube to learn about solar and see if it's for you. Then shop around for prices as they can range from reasonable to ridiculous.