Almost every trailer we have built out has been setup for boondocking ie. off-grid use. When a client comes to us with the desire to use their trailer without being plugged into water, sewer, or electric, the first thing we ask them is for a list of appliances they want to run while boondocking. Certain appliances have a larger draw on your trailer's batteries - and these need to be kept in mind when building your electrical system.
Here are the basics for beginning to design the electrical system for your off-grid camper. For an off-grid trailer, here is what we recommend your system include:
A Converter - This takes your shore power (AC) and converts it to DC power (12v system) and charges your batteries the quickest through shore power.
An Inverter - This takes your 12v (battery bank) and converts it to AC power (your outlets, plug-ins for certain appliances). Size will depend on your 110v power requirements when not plugged into shore power.
Batteries - We like the AGM or Lithium Iron batteries
Lead Acid Batteries - These are less expensive, higher maintenance
AGM Batteries - These are a little more money, but no fuss no muss
Lithium Iron Batteries - This is the most expensive option, the lightest weight and offers more charge cycles. You can also deplete these down to 0 and recharge them.
Solar Panels - We are partial to Zamp Solar because they're based here in Bend, they are made in the US and they make lower profile, longer panels that fit nicely on Airstreams
Renogy is a good option for a less expensive setup and if you like having all of your components from the same supplier, they build panels, batteries, chargers, and inverters.
Propane Appliances - Propane appliances can draw little to no battery supply. Here are a few main appliances that can be propane:
Catalytic Heater or Furnaces - There can be a large battery draw using a furnace if your fans are on all night
Water Heater - We've used the Suburban Instant Hot Water Heater in almost every build, and have been incredibly happy with it
More 12v than 110v
The number of solar panels you want and the size of your battery bank is going to depend on what it is you want to use while boondocking and we recommend monitoring your energy draws regularly.