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Power On
There is an enormous range of 12V appliances and accessories available for Campervans and Motorhomes, all requiring a reliable 12V power supply.
Your Campervan or Motorhome needs three things for a reliable and sustainable 12V power supply:
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- adequate battery capacity to power all appliances;
- adequate battery recharging sources, including appropriate regulators;
- appropriate cabling and connection of appliances and devices to the battery.
All these bits and pieces can be installed permanently or fitted temporarily. Regardless of which option you choose, all your 12V appliances must be connected to the power supply with suitable gauge cable and robust (and correctly fitted) cable terminators and plugs, for both safety and functionality. This is important – in some applications it is critical.
More 12V info…
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Your 12V ‘house’ appliances are powered independently from your vehicle’s starting battery, though the battery/s powering your appliances can still be recharged from your vehicle’s battery charging system using an isolator / regulator.
This video provides a good overview of 12V off-grid equipment options:
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- Easy Off-Grid Camping System (4WD SupaCentre)
Listed below are some DIY options for providing and maintaining a 12V power supply in your Campervan….
| * Prices are approximate and are in AUD | *Links are to examples of the device category | ||||
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Battery capacity? Check your appliances’ rate of consumption of electrical current (amps) – this will determine the type of battery (AGM or Lithium) and the storage capacity (Ah) required for a Power Station or battery.
A 120Ah Lithium battery has a ‘usable’ capacity of around 96Ah (80% of specified capacity*). A 12V fridge drawing 2 amps (when the compressor is running) will deplete 1.5 Ah per hour from your battery, so you have a ‘safe’ runtime of around 65 hours from a fully charged 120Ah Lithium battery (with no recharging). A 120Ah AGM battery has a ‘usable’ capacity of around 60Ah (50% of specified capacity). The same 12V fridge, consuming 1.5 Ah per hour will have a ‘safe’ run-time of around 40 hours from a fully charged 120 Ah AGM battery. You can estimate when an AGM battery has reached its 50% charge capacity when the voltage drops to 12.1V.
* Some Lithium battery suppliers claim 100% usable capacity. Maybe. Let’s play it safe and stick to a guideline of 80%, which will ensure battery operability and a longer life-span.
Battery Charging – Of course, the estimated appliance run-times above are based on the initial capacity and subsequent discharge rate of a fully charged battery. Deep-cycle batteries can be recharged to restore their capacity and significantly extend the run-time of your appliances.
Your batteries can be recharged with electrical current generated from a solar panel, the vehicle alternator, or a 230V mains supply, via an appropriate charger / regulator, which can extend your appliance run-times indefinitely, if you have enough recharging capacity.
Thinking of an inverter? Inverters are used to run portable 230V AC appliances from your 12V DC battery/s. However the amps drawn from a 12V battery by domestic 230V appliances operating through an inverter can be huge – calculated (approximately) by dividing the power draw of the appliance (Watts) by 10. For example, a 700W toaster will draw around 70 amps, consuming around 1.2 Ah per minute from a 12V battery.
A low wattage inverter (under 1000W) connected to a battery with 100Ah or less in capacity is more suited to charging laptop computers, running CPAP machines, etc, rather than powering larger domestic appliances. A battery’s capacity to supply a high continuous current is a consideration here too – Lithium batteries are an advantage in this scenario.
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| 12V Power – Option A: | Portable Battery Box | |||
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Powered Battery Boxes hold your battery securely, providing external connections for Anderson plugs, 12V cig sockets, USB sockets, and screw terminals. They are also fitted with a voltmeter, which can be used to estimate how much charge you have left in the battery. If you fit an AGM battery, and include a 230V charger in your kit, a Battery Box option is probably the cheapest portable 12V power option. For overnight or weekend trips, running only a fridge and mobile phone charger, it is likely that, with decent battery capacity, you may not need any on-site re-charging….
See also: Portable fridge & 12V power on the go >>> For longer trips, a solar panel and/or 12V DC-DC charging facilities will provide longer battery runtime….
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Battery Box – Option 1Adventure Kings Battery Box – (Holds 120Ah AGM or Lithium battery) – Includes 2 x 30A Anderson plugs, 2 x USB outlets, 1 x 12V cig socket, 2 x screw terminals, 1 x Voltmeter, isolation switch, resettable circuit breaker. (~$60) |
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Battery Box – Option 2iTechWorld GoFurther Box – (Holds 120Ah AGM or Lithium battery) – Includes 1 x 175A Anderson plug (for Inverters, etc), 4 x 50A Anderson plugs, 3 x QC 3.0 USB outlets, 1, USB-C outlet, 2 x 15A 12V cig socket, 2 x screw terminals, 1 x LCD screen, isolation switch, 2 x 50A auto-reset circuit breakers. (~$300) |
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Battery Box – Option 3iTechWorld GoFurther Box & Charger – (Holds 120Ah AGM or Lithium battery) – Includes a 25A DCDC Charger (with 1 x Triple Anderson plug for DC-DC ignition source input & 1 x 50A Anderson plug for DC-DC MPPT solar input), 1 x 175A Anderson plug (for Inverters, etc), 4 x 50A Anderson plugs, 3 x QC 3.0 USB outlets, 1, USB-C outlet, 2 x 15A 12V cig socket, 2 x screw terminals, 1 x LCD screen, isolation switch, 2 x 50A auto-reset circuit breakers. (~$600) |
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| However, if you are considering a Lithium battery, with AC and DC chargers, and maybe an inverter, along with the various plugs and fittings, and vehicle installation, it may not be worth the effort (and cost) when compared to the simplicity and functionality of a Portable Power Station…. | ||||
| 12V Power – Option B: | Portable power station (the easy option!) | |||
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These power stations have become a more widely available option in recent times with the advent of affordable Lithium batteries and good quality power inverters. A portable power station provides a reliable 12V power supply for your fridge and other 12V accessories (lights, fan, etc), along with the option of 230V for small appliances (like a sandwich press) and USB charging points for all your portable devices – as well as all the required built-in infrastructure for re-charging the power station battery from the vehicle alternator, a 230V mains supply, or a solar panel – all contained in a single portable box. They can be used during the week for power on a worksite or in the back yard, then double up as a camping power supply on the weekends. Larger models can even run your domestic household appliances (eg – freezer) for short periods in the case of a power outage. The only decision to make is how big do you want to go (and how much money do you want to spend).
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Power Station Option 1 |
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Power Station Option 2 Self-contained Lithium power station – 50Ah – A medium capacity Lithium ‘Power Station’ for longer run times for refrigerator, LED lights, fans, etc. Includes an AC inverter (PSW – 500W) and a variety of 230V, 12V and USB outlets. Recharge from 230V, car, or solar. (~$900) |
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Power Station Option 3 Larger capacity portable power stations are also available, but they do become expensive! See Goal Zero >>> |
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Power Station Option 4 Lithium power station (50Ah) + Solar panel – Combine a self contained power station, built around a Lithium battery with a built-in 230V inverter, and a 200W solar blanket. Outlets for 230V AC, 12V DC and USB. Built-in lithium battery recharges from solar / 12V / 230V (~ $1500+ AUD) |
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| 12V Power – Option C: | Permanent battery and charging installation | |||
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For a more permanent setup, a battery (or batteries) can be tucked away in a cupboard or under the bed, and wired permanently into the electrical system of the van. This is the most common setup in a Campervan or Motorhome. In addition to the battery/s you will need a battery charger and wiring infrastructure to connect your camping batteries into the electrics of the vehicle, to provide for the alternator to charge the batteries when the engine is running. Note: As a result of new Australian Design Rules (ADR), introduced in late 2022, it is likely that you will also need a vented ‘battery closet’ in which to mount and store the battery/s, so they are sealed from the house area of the van. More info here when implications of the new ADRs are clear, and commercial products to meet these needs are available. |
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| Batteries | ||||
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You basically have two options for a permanent battery – an AGM battery or a Lithium battery. Lithium is the way to go if you can afford it. They cost about $900 for a good quality 120Ah battery compared to around $300 for a similar capacity AGM battery. But they are half the weight (no lead) and provide a more consistent and longer lasting 12V power supply. (There are cheaper Lithium options available – around $500 – though there are questions around the performance of these cheaper batteries over time, especially when operating under regular high-current-draw conditions.) |
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Option 1 Permanent battery – 120Ah – A permanently fitted deep-cycle AGM or Lithium ‘house’ battery (100Ah+) will power a 12V fridge, lights, TV, water pump, etc. ($300 for AGM to $1000 for Lithium). Recharge from alternator, solar panel or mains power. (Battery chargers/regulators required). |
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Option 2 Single 200 Ah and 300 Ah Lithium batteries are also available – check the installation space you have available. |
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| Battery Recharging | ||||
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Your battery/s need to be recharged to maintain their energy supply. Each of the options below can be used to recharge your house battery/s. A combination of all the options below will provide flexibility to be able to recharge your battery/s in various environments.
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Option 1 Vehicle Alternator – Your vehicle’s alternator is charging the starting battery whenever the engine is running. Harness the output from your alternator (via a suitable isolator/regulator) to recharge your Campervan house battery. Read more about Battery Charging >>> |
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Option 2
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Option 3 Important: Mains power connections to your van must be installed by a licensed electrician. |
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| Charging regulation | ||||
| You need a battery charger / regulator to adjust the output of the charging source (solar panel, alternator, 230V) to suit the charging requirements of the battery/s. | ||||
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Option 1 – Solar panel only Look for an Anderson plug connection rather than alligator clamps to connect to the battery. Not required if you are charging a power station that has a built-in solar charger. |
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Option 2 – Vehicle alternator + Solar panel
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Option 3 – Mains Power Important note: Mains power installations must be carried out by a licensed electrician, with an appropriate circuit breaker installed.
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Very basic – Vehicle alternator only |
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| The Hookup | ||||
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Nothing else matters if you don’t get this right… Installing a battery, a charger, a solar panel and a fridge is the easy part. Connecting it all together requires careful planning, based on an understanding of good electrical installation practice.
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| Other stuff | ||||
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Gauges, panels & outlets – Use a distribution panel with a built-in voltage meter to monitor your battery state of charge (AGM batteries) and to provide outlets to connect various portable devices. Wide variety of options available. From $100. | |||
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Fitting a Battery Monitor – Check % battery charge (SoC), incoming and outgoing current, voltage and remaining battery capacity. Can be used for both AGM and Lithium batteries. ($50 – $200) | |||
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Inline Power Meter – Connect between your portable solar panel / regulator and battery to measure how much current is being returned to the battery from the solar panel. ($30) | |||
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Installing an Inverter – Run 230V appliances from your 12V power supply. (There are some limitations – read more here.) ($200 – $1500) | |||
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Fuse box – Provide a fuse link for each permanently installed 12V appliance. Various options available from most RV parts shops. | |||
12V cabling – There is cabling and there is cabling. If you want reliable 12V power you MUST use quality cable and cabling techniques to hook everything together. There must be a suitable gauge cable path for electrical current to move from your battery to your appliances, and back again, without any cabling hindrances.
If you are planning on a basic van setup, with a bed, a fridge and a portable water supply for weekends away, then a self-contained power station is without any doubt the easiest way to get up and running with a reliable 12V power supply.
More detailed info about a sustainable 12V power supply:See also:
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DIY Fit-out | What size van? | Draw a floor plan | Cabinet materials | Fittings | 12V power