We have used the Outback Power 2012 (2000 Watt / 12 Volt) inverter charger for the last five years and it has been awesome. It is a duty rated system designed for 24/7 usage even at 2000 watts. They are commonly used in off-grid homes but do make Mobile editions of most options. You can also get one in 24v to match up your chassis voltage and can set it up to use the altenator/generator power to also charges while your driving. It is a three stage charger and programable to charge your batteries according to manufacturer spec. They also provide a five year no questions asked warranty.They are around $1500