People often ask me what solar panels they need for camping situations so I thought I would pass on some general information to help those looking to set up travel vehicles with Solar.
I have a lot of experience with solar panels for camping, caravans and travel vehicles generally. When you travel a lot solar panels are very useful for two essentials, lighting, and 12-volt refrigeration. They can provide power for other items as well and with sufficient panels and batteries can provide power for other 240-volt appliances through an inverter.
Why do people need Solar Panels for Camping?
Solar Panels, in an outdoor camping scenario, are designed simply to recharge 12-volt deep cycle batteries. You need enough panels to charge the batteries during the day so that the power is stored and used overnight, then recharged the next day.
For most people, this means using a 12-volt compressor fridge, LED lights, 12-volt phone charging, a water pump for taps, and perhaps your television.
Update – this applies to lead acid batteries (which includes Gel and AGM. Rules for Lithium batteries are different.
The battery bank needs to be sufficient to supply power through the night so that the voltage early morning gets only to around 12 volts. This helps extend the life of your batteries. It is not good to go much lower than this.
Batteries will work lower, but this is not good for the batteries and it is harder for the solar to recharge during the day. Often, as in the case of operating a compressor fridge, you have a draw on the batteries during the day whilst at the same time recharging with the solar panels, therefore the storage capacity is as important as the solar supply itself.
For lighting, a water pump and a small amount of TV time about 120 watts of solar together with a 100 amp hour deep cycle battery are sufficient. However, adding a fridge is a little more complicated.
What Combination of Batteries and solar should you have?
The rule of thumb is that you need to allow at least 2 watts of solar per litre of the fridge and 3 watts of solar per litre of the freezer. This is for a chest-type 12-volt compressor fridge. Uprights require more allowance because when you open the door the cold air escapes quickly. Gas (3-way) fridges are not suitable for small solar systems.
Likewise, you need a big enough battery system. It is recommended that you use around 100 amp-hours of battery for around a 50-litre fridge and perhaps a little more for a 50-litre freezer. For larger units, use a larger battery bank.
This is assuming that you are remaining outdoors, and not just going away for the weekend and can afford a slow loss over a couple of days.
There is always the odd cloud in the sky or a hotter day when the fridge is opened more often – or someone drops by for happy-hour and the fridge gets used a little more. For this reason, I say at least. Always, a little more is beneficial.
What types of solar panels are there?
There are basically two types of solar panels. Fixed and Portable.
Fixed panels, as the name suggests, are permanently mounted onto a vehicle and are always connected, via a regulator, to the battery.
Unless it is extremely hot you will need to find
However, you would be surprised how many roads in Australia have trees along them placing your panels in the shade whilst travelling. However, this is still a very good option.
Unless you have a large system with a small power draw this needs to be supported by some sort of supplementary charging.
This could be folding panels, DC charging, a generator or plugging into the mains somewhere.
Portable panels, are generally folding with their own regulator on them, and can be put out when stationary and hooked directly to your battery bank.
Traditional portable panels were glass with an aluminium frame, however, we now have other lightweight materials including light aluminium and canvas-style blankets.
Portable panels can work alongside fixed panels and if you have more than one battery (which if you have two sets of panels is most likely) then you can connect each panel to different terminals in the battery bank. (Your battery bank should be set up in parallel rather than as two separate units )
I found a YouTube video which explains this perfectly.
This means one solar set goes to the positive of the first battery and negative of the last battery in the bank and the other panel set goes to the negative of the first battery and positive of the last battery.
Size and placement of solar and Battery.
Unless you have a large roof on your travel vehicle, there may be limited space to place fixed panels.
Some people like me, have a bus, truck or large motorhome and can place panels on the entire roof. This means that you can have larger battery banks, more panels and larger inverters to run more appliances off the batteries.
I have 1100 amp hours of battery and a bit under 4,000 watts of solar and run most of my motorhome on 240v including a large 500-litre household fridge freezer.
And yes, there are times when I need to charge my batteries with my generator. I also have a DC battery charger, so I charge the batteries whilst driving.
Solar panel warranty.
When selecting a panel, check out the warranty. Most of the good brands have a warranty for 20-25 years for power output. This is a good indicator of the expected lifespan of the panel.
Although technology will definitely change in time, the longer the warranty the better you can expect the quality to be.
The other thing to be careful of is that there is higher voltage for houses and lower for camping. Whilst both may be good quality, 36-volt regulators sometimes don’t start charging until the voltage on the panel is higher. You need to research carefully when selecting both panels and regulators
Sometimes high voltage panels can give you can get less charge time during the day – which can mean you may need more panels to do the same job. With most vehicles, you are limited for space so I highly recommend 21 or 22-volt crystal for charging your 12-volt system.
Solar is a very good way to charge your batteries, but like all systems, it is not the only answer unless you simply want to go without a 12-volt fridge, TV, or technology, and use battery-operated lights.
Most of us have done this in the past, lighting fires and the like. However, if you wish to travel full-time and free camp, solar is definitely worth the money.
Hope this was helpful.
I hope that you are enjoying my posts and please leave a comment below if you have any questions. You can also follow me on social media and I would love it if you could share my posts.