Camping and off-roading are two of Australia’s favourite pastimes. Loading up the 4WD and heading off the beaten track is a great way to find adventure, and it’s some of the most affordable fun you can have. But what do you do for power when you want to spend long stretches on the road? Modern solar panels and battery systems can provide plenty of juice for a weekend, but our customers often want to know what it takes to go fully off-grid. So, can I go off grid with solar panels? There’s lots to think about when designing an off-grid system for your caravan, 4WD or adventure vehicle, and in this article we’re going to help you get started.
Can I Go Off-Grid with Solar Panels?
The simple answer is yes! Paired with enough battery storage, you can use solar panels to go off-grid almost indefinitely. Modern solar panels provide plenty of power for things like mobile phones, laptops, camp lights and even fridges and freezers.
Of course, going completely off-grid is a serious challenge, even if you cover your caravan in solar panels. The major limiting factor here is battery storage. Deep cycle batteries are often big, heavy and expensive, and you’re going to need several of them if you want to power your set up without shore input. But that’s not the only challenge. Solar panels are highly effective on sunny days. But what happens when it’s cloudy for weeks in a row? If you want to go off-grid for long periods of time, these are things you’re going to have to think about when designing your battery and solar set up.
How Much Solar Do I Need to Go Off-Grid?
The simplest way to calculate your power needs is compare the wattage provided by your solar panels to the power consumed by your devices. A Watt is a unit of energy that’s calculated like so:
Volts x Amps = Watts
The solar panels found on most 4WDs produce anywhere from 100 Watts to 150 Watts each. You can compare those output figures to the power being drawn by each of your devices. This is where some people get lost, because we often measure power consumption and battery capacity in a unit called Amp Hours. Amp hours is calculated like so:
Amp draw x Number of hours in use = Amp Hours
So, if your phone charger draws 2 amps, and it takes 2 hours to charge your phone, it’s consuming 4 Amp Hours of power per day. To calculate how much solar power you need, you’ll have to make a list of each of your devices and calculate how much energy they use in a day. The table below shows a rough estimate of how much power you might use in an off-grid camping set up:
Amp Hours (Ah)
Calculating Solar Usage
Using our example above, we know that we use about 74Ah of power every day. That means our solar panels need to replace 74Ah of power or more. To compare those 74Ah to the wattage of our solar panels, we can use the formula from earlier to convert the figures:
74Ah x 12 volts = 888 Watt Hours (Wh)
Same as with Amp Hours, Watt Hours is a measure of power over time. If a solar panel is rated at 100 Watts, it can produce up to 100 Watt Hours of power in an hour. Now, we also know that most solar panels don’t run at 100% efficiency all day. In Australia you can expect to get about 6-8 hours per day of good sunlight that you can use to charge your batteries. That means we need to generate 888 Watt Hours of power in 6 hours, or the equivalent of about 148 Watts per hour, which could be provided by a single panel!
Adding Battery Storage
That was a lot to get through, but we’re on the home stretch. Once you know how much power you’re going to use in the average day, you can calculate how much battery storage you’ll need.
If you want the longest life from your camping batteries then you need to monitor how much of the total power is being used on a daily basis. We refer to this as the safe “Depth of Discharge.” Keeping within your battery’s Depth of Discharge rating can extend its lifespan by years, or even decades. The safe depth of discharge for common deep cycle batteries is as follows:
- Lead acid. Lead acid batteries should only be discharged to about 50% capacity.
- AGM. AGM batteries can discharge about 70% of their total capacity.
- Lithium. Lithium batteries can be 85-100% discharged.
Depth of discharge effectively means that you can’t use your battery’s full capacity every single day. For example, an AGM battery that’s rated at 100Ah should only provide about 70Ah of power before being recharged. When designing your off-grid solar set up you need to consider your average daily usage and whether you need redundancy. Our 100Ah AGM battery could provide enough power if the weather is consistently sunny. But, if it’s overcast for several days, we’ll need additional power or an alternative way to charge the battery (such as the vehicle’s alternator). In most cases it’s safer to build redundancy into your system by adding extra batteries, rather than relying on the sun to provide all the energy you need to go off-grid.
Design the Ultimate Off-Grid Solar Systems Brisbane with Access Auto Electrics!
If you’re heading off the beaten track but don’t want to give up your creature comforts, it’s hard to beat the convenience of an off-grid solar set up! Off-grid solar systems for 4WDs, caravans, boats and campers can make all the difference to your comfort, both on and off-road. Designing an effective solar system can be complex, but Access Auto Electrics makes it simple!
Access Auto Electrics is an experienced team of auto electricians who offer camping fridge hire Brisbane wide. We design a wide range of off-grid, camping and solar set ups and towing accessories Brisbane wide for vehicles of every kind. Whether you need power for a single weekend or extended off-grid stays, we can design a system that meets your needs. Get in touch with us to find out more, or phone us on 07 3366 8585 for a consultation, whether it's vehicle diagnostic services or Off Grid Solar Systems Brisbane wide!