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How to Plan For Your Off-Grid Electrical System

How to Plan For Your Off-Grid Electrical System

Summary: Follow below for pro tips on how to be best prepared to be off-grid and not be caught out.

Topics: 4x4, tech, Off road, Aftermarket

How to plan and prepare for your off-grid electrical system

When the time comes to start thinking about exploring the great Australian outback it is important to ensure you are well prepared for the journey. Questions start popping into your head like, how much fuel do I need? How much water do I need? Do I need recovery gear? What emergency equipment do I need? The list goes on.

What a lot of people find confusing though is how do I make sure I have enough power to supply me when I am off grid? And how do I ensure I am not going to run out of power?

At we have some handy tips to help you with this, & we also have all the essentials you will need to get you on your way and keep you out of trouble.

Did you know are able to help you design your own electrical system and assist you in your install process?

Calculating the Load of Your 12V Devices

Before hitting the road, it's crucial to grasp the total electrical load your caravan's 12V appliances exert on the system. Everything from your lighting to the fridge has a specific current draw (measured in amperes or amps). Here's how to calculate it smoothly:

  1. List Your Devices: Begin by cataloguing each 12V device you plan to use.
  2. Find the Amperage: Check the device itself or the manual for its amp rating. If you can’t find the amp rating, you can find the wattage of the device. By simply calculating the Volts / Watts you will have the amperage of the device. For example:

A 12V fan is 4 Watts. Divide 12 by 4 and that gives you 3 amps.

  1. Sum Up the Total: Tally the amperes for all devices to find your total amperage requirement.
  2. Count the total running over time: If your fan draws 3 amps for 10 hours that would have drawn 30 amps from your battery. If your battery is a 100ah then you would have 70% left in your battery.

Imagine you have three lamps at 2 amps each, a fridge drawing 5 amps, and a TV at 3 amps. Here’s how you'd compute that:

Total Amperage = 2A + 2A + 2A + 5A + 3A = 14A

This figure is vital as it directs you to the suitable battery and solar capacity.

Determining Your Battery Needs

Choosing the right battery involves understanding both the load it needs to support and the duration you require its service without recharge.

Estimate Battery Capacity

Battery sizes are given in ampere-hours (Ah), which tells you how much charge a battery can store and deliver over time. Here’s how you calculate your need:

  1. Calculate Daily Usage: Multiply your total device amperage by how many hours a day they run.
  2. Consider Autonomy Days: Decide how many days you need power without recharging and multiply by your daily usage.
  3. Consider Solar & Charger Capacity: Solar only performs at its rated output when the sun is at it’s peak. This is generally only about 4-5 hours per day. Ensure you have enough solar to sustain your batteries & your power usage outside of these hours.

Using our previous example:

Daily Usage = 14A x 4 hours = 56Ah/day

For two days of autonomy:

Total Capacity Needed = 56Ah x 2 = 112Ah

Pick the Right Battery

A Lithium battery is your best bet for a caravan, as recommended by Parts Guru. Opt for one with at least 20% more capacity than your calculated needs to account for any unforeseen power demands.

Optimizing Your Solar Solutions

Solar panels not only reduce your environmental footprint but also keep your batteries charged without reliance on mains electricity. Determining the right number and size of solar panels is crucial:

Work Out Needed Solar Output

Solar panel output is rated in watts, which indicates how much power they can produce under ideal conditions. To find out what you need:

  1. Convert Amps to Watts: Multiply your daily amp-hour needs by your system’s voltage.

Daily Watt-hours = 56Ah x 12V = 672Wh/day

  1. Calculate Based on Sunlight Hours: Divide the daily watt-hours by the average peak sunlight hours your location receives.

If you average about 5 hours of sunlight:

Needed Solar Power = 672Wh / 5 hours = approximately 135W

Choose Adequate Solar Panels

Select panels that provide slightly more than your calculated needs to ensure coverage during less sunny periods, as suggested by Parts Guru.

System Integration Tips

Properly integrating your battery and solar system with devices like a solar charge controller can significantly enhance efficiency and battery life. A charge controller regulates the flow of energy and prevents overcharging, a crucial aspect highlighted by Parts Guru.


Understanding and managing the electrical demand of your caravan’s 12V devices, along with the appropriate battery and solar configuration, ensures that your journey remains powered and pleasant. With these strategies, you’re well on your way to a worry-free adventure.

For more expert advice and top-quality caravan parts, visit Parts Guru.

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