When it comes to solar, bigger power (or more ‘watts’) is generally better – it means you can charge your batteries up faster and make the most of the sun while it’s out – you never know when the clouds will come over and hide the sun – and even a couple of overcast days can be enough to ruin your holiday if you were banking on eight plus hours of perfect sun every day! So first it’s important to size your deep cycle battery correctly and in most cases bigger is better here too! The bigger your camping battery, the more power you’re able to store for those times when your solar isn’t working whether that’s overnight or on overcast days. If you’re running a fridge and other 12v gear, having a bigger solar panel will be able to supply enough power to charge the battery and run the appliances at the same time. A smaller panel may only just cover the power used and never actually charge the battery up, or not supply enough causing your battery to still discharge slowly – which is a big issue once the sun goes down and your fridge keeps running as your solar panel may never catch up.

So how many watts do you need? Well, it depends on your setup and how much 12v gear you want to run – if you’re running a fridge up to around 65 litre in capacity then with a 120W Solar blanket with MPPT regulator you’d need about 6 hours of good sun per day to cover the fridge power usage over 24 hours. Upping your solar power to a 160W panel or 200W blanket would mean you’d need about 4 hours of sun to cover usage and then stepping up again to a 250W folding solar blanket or 250W folding solar panel would need around 3 hours of good sun per day to cover what your camping fridge will use in terms of amp hours. If you stepped up to a 70 to 90 Litre fridge then you’d need to upsize your solar too – in this case you would need 6 hours of good sun per day if you had a 160W fixed panel or a portable 160W folding panel or 200W Folding solar blanket with MPPT. Up sizing to a 250w Folding panel or 250W folding blanket with MPPT would require about 4 hours of good sun. If you wanted a permanent setup then you’d need at least two 110W panels, or even better a pair of 160W panels! Finally if you only were getting 3 hours of ideal sun per day then you’d really need a minimum of 2 panels or blankets that are at least 160W in power and even better would be a pair of 200W folding solar blankets.

If you’re intending to use your 70 or 90L fridge as a dual zone fridge Freezer (that is where one side is a fridge and one is a freezer) then you might need to expect up to another 50% more power usage and upsize your solar power accordingly. Of course this is all based on the idea that you’re not intending to drive your car at all and you’re just sitting at camp – because if you were planning to drive, even an hour a day, then a DC-DC charger will make huge difference to the length of time you could be camping! The Adventure Kings 25A DC-DC has a built in MPPT solar regulator that means you can charge your batteries while you’re driving and while you’re sitting at camp with the one system – this ensures your batteries get the right charge to keep them happy and healthy and the other big benefit is that the 25A DC-DC Charger can accept up to 360W of solar and use that power really efficiently and effectively. With a one hour drive, you could be charging your battery one third up to one half of what is required and then your solar wouldn’t need to work anywhere near as hard, or as long to make up for the power usage of your camping fridge.

All solar panels are tested to the same standard test conditions so you can compare them like for like. The panel is tested at 25°c, with 1000 watts per m² of sunlight, an air mass 1.5 (am1.5) and no wind with the panel pointing directly at the light source. A 250W folding solar panel puts out the same power as a 250w folding blanket. So that means, 250w panels from different brands will both put out 250w (assuming the seller is being honest! The difference between brands and types of panels is just how big they need to be to get that amount of power in the same standard test conditions – a panel that’s twice as efficient will be half the size! Where output changes is often in the real world and depends so much on the individual setup and the conditions – for example when a solar panel heats up in the sun it may lose up to 10% power due to inefficiency. The main things to consider are the weather and the direction / angle your panel is facing. If it’s raining and overcast your panel will be putting out very little power and at dawn or dusk, if your panel is laying flat it won’t be working at full power. Similarly if it’s the middle of the day and the sun is above your panel, but it’s facing west it won’t be putting out as much power. The difference between a panel pointing directly at the sun on the correct angle, and a panel laying flat on an overcast day can be as much as 80%!