I am looking for a design to achieve the following. I have an off road camping trailer with a second deep cycle battery installed. The second battery never reaches full charge because of the voltage drop from the alternator in front to the battery in the rear of trailer To charge the second battery in the trailer to its full capacity from the tow vehicle I use a 12v to 220v inverter and then a 12v battery charger. Very inefficient and bulky. Where can I find information to assist in designing a 5-12volt(dc) input to 13.8v(dc) output voltage booster/inverter that can deliver 30 amps.