A 98Ah deep cycle battery will let you run a 45L Camping Fridge for around 50 hours, assuming that the compressor fridge is drawing around one amp hour on average. Of course how efficiently a 12V fridge/freezer runs is affected by temperature, how many times you open your camp fridge and whether you add more items into the portable fridge that need to be cooled down. When you think about it, 50 hours is more than two full days and nights – which is perfect for some campers. But if you wanted to extend the run time of your camping fridge/freezer without getting more battery capacity, one the best and easiest ways is to connect a portable solar panel to your setup every day of your trip! Now so long as the sun is out your camping solar panel will be charging your camping battery, or topping it up so the deep cycle battery is going to stay at 100% capacity.

Once the sun goes down your camp fridge is continuing to draw power… let’s imagine the sun goes down at 6PM and wakes up again at 6AM, but you’re camped near a tree line and the sun doesn’t really hit your campsite (or your camping solar setup) until 8AM. By 8AM your fridge has used 14AH of auxiliary battery capacity, so when your 12V solar panel starts working again, you’re already down to 86AH. If you only have a camping solar panel capable of less than 60Watts, even in ideal conditions your camp solar panel will be only able to supply enough to keep it at that level of charge all day until the sun goes down again. The next morning you wake up and your deep cycle battery is now down to 72AH… This will continue for a couple days until you reach 50% capacity and really need to charge your auxiliary battery back up otherwise you’re starting to cause potential long term damage and drop in overall capacity. This is of course only true in ideal conditions too, so in the real world it’s so important to upsize your camping solar setup to the biggest you can afford and manage in your vehicle!

The only way to solve the issue is by stepping up to a larger battery, a more powerful solar panel or ideally both! Running two 98AH AGM deep cycle batteries and a 160W Solar panel with MPPT regulator would extend your camping time massively. But you still need to be aware that poor weather, not-ideal camping solar panel angle and panel temperature will affect the portable solar panel output – plus the ambient temperature, what your camping fridge is set to, how many times and how often you’re opening your 12V camp fridge and whether it’s copping any sun will affect how much power your compressor fridge is using. Plus you might want to run more than just a camping fridge! So anytime you charge your phone or turn on any LED camp lights you’re using more power that your portable solar setup has to add back in.


Each battery will also have a maximum charge rate – this is a limit for charging current that you shouldn’t exceed, but also means that bigger batteries can accept more charge and therefore charge at a higher rate than smaller batteries. For example, a 115Ah AGM deep cycle Battery can be charged at up to around 30Amps. The second point here is that once an AGM battery reaches max charging voltage, the current allowed into the battery from the solar regulator will decrease – so being able to get more current into the battery early is great and is another big positive of a bigger portable solar setup – such as 250W Folding Blanket. While it’s capable of putting out max power around 20 Amps, the deep cycle battery will eventually limit the amount of power coming in once it has reached maximum voltage.

Let’s look at a real world example!  If your portable camping solar panel can put out a maximum of 10 Amps, consider that you’ll lose some power output in real world conditions, let’s say it’s now at 8 Amps. Plus it’s an extremely hot day, so your camping fridge is working harder, plus you’re opening your fridge to grab cool drinks more than usual… so it’s drawing 2Ah on average. Next you’re also charging a phone or tablet from your battery, using about another A/h per hour… You’re now only getting 5A of actual charge going into your deep cycle battery from your portable solar panel that is capable of a possible 10A. If your auxiliary battery is almost full, then running 5 Amps is enough to keep it topped up – the battery probably can’t accept much more than that anyway with its state of charge. That means it’ll easily stay nice and charged overnight… If on the other hand your house battery is already down to about 60 or 70% capacity, the 5 amps coming from your undersized solar panel is now not ideal! The battery can accept a much higher rate of charge so it’s going to take even longer to reach the maximum voltage, so you may never fully charge up your battery in this situation! So, you need to upsize your camping solar setup to take into account not only the weather and the real world, but also the properties of your deep cycle battery and the way it will charge – in the above example a 250W solar Panel capable of up to 20Amps of charge could’ve put in 15 amps of charge instead of the smaller panel’s five amps – and that makes a massive difference to your battery charge and how long you can happily stay at camp!