Maybe you should do a bit more planning before pulling the trigger? When I use to precharge my hybrid battery I also put the starter battery on charge. Someone referred to it as a mini phev mod. I did it to top off the starter battery to get max mpg.
My current setup was used with parts from around the house. The batteries were from an electric wheelchair I currently do not use, the charger was for my father to use since its soo light weight. The inverter was to use during power failures, but we got a generator now. The mean well power supply was to repair a mini fridge. Then I hacked up an extension cord from the dollar store for wire and used the cord from a bad power strip to plug it into the inverter. The only thing I purchased was the light switch for 70 cents and the zip ties. Hell, the lumber was in my yard and the fan was from an old pc I put a better one in.
Ive made a tank of gas last 2 weeks now.
I think PHack has a small solar panel on his hood. Not sure if it helps to top off the starter battery or if it serves another purpose. I got a few myself 5,10, 12 and a 15 watt panel. I had considered wiring 2 panels of the same size in series to ensure I have enough voltage in indirect sun light to be useful.