Camper Van Electrical – Add Inverter-Charger

This section covers adding a 1200 watt Samlex Inverter/Charger. The inverter/charger works this way: when you are running on your house battery, the inverter part of the inverter/charger will power 120 VAC appliances in the van. When you are on shore power, the charger part of the inverter/charger will charge the house battery from the shore power. So, it basically combines and inverter and a shore power charger into a single unit.

Combining the inverter and charger in a single unit makes things a little simpler and the unit automatically handles the transfer from inverter to shore power and vice versa.

Samlex 1212F Inverter/Charger

The Samlex is Inverter/Charger is a high quality unit that is built like a tank – it weighs 39 lbs and is used in a lot of commercial applications. I did some testing on it including tests at high loads, running sensitive devices (microwave) and running it at low voltages – it did fine on all of these. The only negative is that the cooling fan is a bit loud when on.

One thing to be aware of with this Samlex is that the remote control is pretty much a necessity. The remote is the only way to make all of the settings (battery type, …).

There are other inverter/charger choices out there from Victron, Renogy, … in case the Samlex does not appeal.

Wiring diagram

Take some care in locating the inverter/charger. It requires some ventilation space – see the manual. The heavy cables from the unit to the hub should be kept as short as feasible to reduce voltage drop. The unit is heavy, so it will require good mounting to stay in place in case of a crash.

The inverter/charger has been added to the wiring diagram below. Only three new wires to hook up.

Inverter/Charger added to the base system
Base system with inverter/charger added
Back of inverter/charger showing connections.

Wiring

DC Wiring

Connect an AWG #2 cable from the positive (red) terminal on the inverter/charger to one of the four high amperage terminals on the Hub. Both ends of this cable have 5/16th inch (M8) lugs. Use a 200 amp AMI fuse on this terminal. If you have a torque wrench, the torque is 180 in-lb.

Connect the negative (black) inverter/charger terminal to one of the large negative terminals on the Hub.

Try to keep these supply/return lines as short as possible to minimize voltage drop on these high amperage runs.

Connect a wire from the grounding terminal on the inverter/charger to either a negative return terminal on the Hub or to a prepared chassis ground – use at least #6 wire.

AC Wiring

There really is no AC “wiring” – just plugging things in.

Using this adapter cord, connect the shore power outlet to the matching socket on the back of the inverter/charger – this provides shore power to the inverter/charger.

Plug a plug strip into one of the regular house power outlets on the back of the inverter. Locate the plug socket where you want your 120 VAC outlet in the van.

That’s all there is to it. The inverter/charger will automatically sense whether you are on shore power or inverter power and send juice to the power strip either way. It also automatically bonds the AC neutral to its ground when on inverter power as required for safety.

My first electrical system on this van had a full AC distribution panel, AC circuit breakers, and outlets all over the van. This proved to be a total waste of time, energy and money. We only ever used one outlet by the galley -never used the rest. I just love how this is ready to just use with zero wiring effort.

The 120 VAC power outlets on the inverter/charger are protected with ground fault breakers, so no further protection is required – just plug stuff in.

If you see any errors or misleading material on this page, or if additional information should be added, please let me know in the comments.

Gary 7/21/22

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