Campervan Electrical

Last modified: Dec 4 2020

This document is an up to date description of the campervan electrical system.


The campervan has one bank of AGM batteries and one bank of a single lithium (LiFePo4) battery. The 12 volt lights and appliances can be run from either battery bank. Electricity is supplied by solar panels, an on-board generator, the factory Ford Transit alternator, or 12v volt ‘shore power’ from a household wall outlet and extension cord.

The air conditioner and microwave require 120 volt AC. The lights and water pump required 12 volt DC. The furnace, hot water heater and stovetop are propane fueled, but are controlled by 12 volt electric.

In the current configuration:

  • Either battery bank can be charged by any or all of the charge sources. Charge sources are the campervan alternator, the 200w rooftop solar, 220W portable solar, shore power (plugging the camper into a wall outlet), and a Cummins Onan generator.
  • The alternator can charge the lithium battery bank at a 40 amp rate and the AGM battery at an 18 amp rate via DC-DC chargers.
  • The charger/converter can charge at a 30 amp rate when plugged in to shore power or on generator.
  • The 12 volt lights and appliances can be run from either battery bank. Switching the load between banks is manual.
  • The 120 volt microwave, air conditioner, and outlets can only be used if the campervan is either plugged in or the generator is running.
  • We use about 40 amp-hours overnight, so either driving or running the generator for an hour recovers most of what we use.

The 120 volt AC electrical consists of:

  • A 2800 watt Onan gasoline generator that draws fuel from the Transit gasoline tank and generates 120 volt AC.
  • A 30 amp ‘shore power’ connection that feeds 120 volt AC from a standard 30A campground outlet and extension cord.
  • A WFCO transfer switch that automatically transfers load to the generator anytime it is running.
  • A 120 volt load center with circuit breakers that feeds 120 volt appliances (microwave, air conditioner) and 120v outlets.
  • A Victron charger/converter that supplies 12 volts DC to the 12 volt side of the campervan.

The 12 volt DC electrical consists of:

  • A 30 amp Victron charger/converter that supplies 12 volts DC.
  • A 200 watt GoPower solar array.
  • Two SunPower 110W portable solar panels.
  • One Victron 75/15 solar controller
  • One Victron 100/20 solar controller
  • A SPDT A/B switches to manually transfer solar controllers to either LiFePo4 or AGM banks
  • An OEM Ford heavy duty 250 amp-hour alternator.
  • Two 105 amp-hour Duracell AGM house batteries.
  • One 100 amp-hour Battle Born LiFePo4 lithium battery.
  • Two OEM 70 amp-hour AGM chassis/starter batteries.
  • A battery isolation relay that automatically combines or separates the house 12 volt circuits from the Transit chassis/starter batteries as needed.
  • A Victron programmable low voltage disconnect that disconnects the house loads from the batteries when the batteries are discharged.
  • A Redarc 40 amp DC-DC charger that charges the lithium battery with a LiFePo4 specific charge profile. Limits current to 40A to prevent overload of other charge sources.
  • A Victron 18 amp DC-DC charger that charges the AGM batteries from either the alternator or the lithium battery bank.
  • An A/B switch that manually transfers house load and the 30 amp Victron charger between either the LiFePo4 or AGM batteries
  • A 12 volt load center that distributes and terminates 12 volt circuits throughout the campervan
  • A solid state relay (SSR) that can programmatically disconnect the Redarc charger input from the house 12v system.
  • Two Thornwave battery monitors installed in line with each of the AGM and LiFePo4 batteries.

Details (12 volt)

Campervan Electrical – as built, 10/2020


GeneratorCummings Onan 2.8HGJBB 3800 watt, 120V AC. Gasoline fuel sourced from chassis gas tank. Generator is hanging under the campervan behind the rear axle.
Transfer SwitchWFCO WF-T30 Generator priority 120V transfer switch. Transfers 120V loads to generator whenever generator is running
Charger/ConverterVictron IP-22 30 amp DC charger/converter
12V 120V Load CenterWFCO 8930/50
120V breakers, 12V fuses
Solar PanelsGoPower 100W FLEX-110 100W x 2
Sunpower 110W Sunpower E-FLEX 110 x 2
Solar ControllersVictron MPPT 100/20 20 amp MPPT
Victron MPPT 75/15 15 amp MPPT
BatteriesDuracell AGM Group 31 105AH x 2
Battle Born Lithium LiFePo4 100AH LiFePo4
Isolation RelayPrecision Circuits BIM-160 160 amp isolation relay
Detects charge sources and connects/disconnects house and chassis batteries as needed to maintain charge.
Low Voltage DisconnectVictronSmart Battery Protect low voltage disconnect. Prevents houes loads from discharging batteries below programmable threshold by disconnecting loads. Permits manual disconnection.
DC-DC ChargersRedarc BCDC1240D Battery-to-Battery charger. Charges Lithium battery bank using 12v DC from other 12v sources. Lithium-specific charge profile, 40A current limit.
VictronOrion TR-18 DC-DC charger. Charges AGM batteries via either alternator or lithium battery bank, manually selectable.
A/B SwitchBlue Sea 6007 Four-way battery selector. A/B/Both/Off. Allows load to be sourced from either battery bank, no battery bank, or both battery banks (not a good idea)
On/Off SwitchBlue Sea 6006On/Off battery switch. Disconnects Lithium battery from loads and charge sources.
Battery Monitor (Qty. 2)Thornwave Powermon Model BT-DCPM shunt-based battery monitors. Monitors voltage and current, calculates state-of-charge and remaining capacity.
Solid-State RelayThornwave TL-SSR solid state relay. Allows Thornwave battery monitor to programmatically disconnect the Redarc charger input from the house 12v system.

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