Solar

This looks like a decent kit!
http://www.bimblesolar.com/offgrid/12v/175w-mppt-kit-shang

MPPT Charge controller is a good start as they are way better at converting the panel output to a voltage that the batteries can handle!
https://www.solar-electric.com/learning-center/batteries-and-charging/mppt-solar-charge-controllers.html

I’m finally getting around to this and have decided to go for a 300W panel and a half decent MPPT controller. I also got the optional remote control unit for an extra £20. I think it came to £400ish with postage.

https://www.bimblesolar.com/offgrid/complete-packages/295W-kit-mppt-mounting

I’ve gone for the bigger panel as I’d rather have too much than too little and this set up should also have capacity to support an electric fridge which I’ll get if mine dies. I may need to add a second battery for that as well though.