240V Fridge in a Camper? Are you mad?
When you have a Campervan, you need a way to keep the Beers cold and the Wine chilled. And what most people end up doing is buying a 12V Compressor Fridge. Job Done!
Well, yes, that works and works well, especially in conjuction with a Solar Panel installation to replace the energy the fridge takes.
But there is a price to pay when choosing to run a 12V Compressor Fridge. Literally a price to pay! You really need to pay through the nose for one – a small 45L Fridge like a Waeco CRX-50 is over £500! They are good units and I installed one in the VW T5 Shuttlecamper, but when I got the VW LT Minibus to convert, I thought there must be a better way?
And there is!
I searched for a high-efficiency AC (230V Mains) Fridge and found the Inventor range of Fridges on Amazon.
I chose the 93 Litre Model with an A++ rating as I wanted a larger fridge then the standard Campervan type. But Inventor also make a small 45 Litre with an A++ rating which is the equivalent of the CRX-50 in size which could be handy for conversions in smaller vans.
(note that the fridges above do come and go in terms of availability, so if they are showing as unavailable, they should come back into stock again. I am linking to these units as they are best I have located in terms of power efficiency, noise and price).
The 93L Fridge I bought was significantly cheaper than the Waeco CRX-80 12V fridge which would be the traditional alternative – we are talking a price difference in excess of £500! (£180 vs £700+). Of course, you cannot plug a AC fridge into a 12V DC Socket. It is neccessary to get an Inverter that converts the 12V DC from your Leisure Battery into 230V AC to replicate your household mains supply.
There are different types of inverters and a very wide range of quality of inverters and their capacities and capabilities.
I recommend the Pure Sine Wave type over the Modified Sine Wave (also sometimes called Quasi Sine Wave) as the Pure Sine Wave (PSW) type is the closest to a household supply and you can be sure household devices will work with them.
Size of inverter in terms of how much power they can handle is the next consideration. Inverters are measured in terms of Watts – a 1000W inverter should be able to provide 1000W of power; a 500W inverter 500W, etc. Sizing of inverters can actually be a complex thing. Too large an inverter and you could waste power in the process of converting DC power into AC power; Too small an inverter and it is too small to run what you want. There is also the question of Peak Load Performance (the ‘capability’ part of the selection). Many AC devices have a power surge when you switch them on. You occasionally notice this when say a power tool starts and the lights flicker. To combat this with an inverter, they have a Overload Peak Rating – usually twice what the continuous rating is. But how well this peak rating works depends on the particular inverters design and quality. Some will manage a peak for a few seconds, some for just milliseconds.
An Compressor Fridge – be they AC or DC – has a significant surge on startup, and can be upto 15 times the usual running power. With an DC model, the solution is to use nice fat juicy cables from the Battery to the Fridge to minimise voltage drops and support that high current for the second or so it happens. On an AC Fridge used via an inverter, it is essential the inverter itself can handle the surge and care must be chosen to select the right product for the job.
The Inverter I chose to run my AC Fridge was the Victron Energy 12/500 Phoenix.
Victron make some of the best off-grid products in the world, each backed with a 5 year warranty, and as the fridge will be on 24/7, I wanted an Inverter that could run continuously day after day, month after month, year after year. So Victron was the obvious brand.
This inverter is a Pure Sine Wave Inverter, so that box is ticked (actually, I am not sure Victron do any inverters other than PSW as that is the best and most compatible type).
Now in terms of Power Rating, I looked at the Phoenix range of Inverters and their characteristics. They run from a 12/250 up to a 12/1200. The Fridge draws around 35W when running, so any of the inverters could cope easily with the power when running. However, as mentioned, there is a big in-rush power surge when the compressor starts up and the power can hit over x20 the usual power – so 800W peak is typical.
The 12/250 and 12/375 models have a peak rating below that value, so had to discount them. The 12/1200 could probably power the fridge without any peak overload but that model is not out yet in fact and will be expensive. This leaves the 12/500 and 12/800.
Differently to other makers, Victron quote the rating in VA (Volt-Amps) rather than Watts. the actual Watt rating of the 12/500 is 400W, and for the 12/800 it is 650W. These means both of those inverters would go into overload momentarily on the Fridge startup.
So why did I chose the 12/500? The design specification of the inverter includes the ability to handle a peak of 900W. As the fridge will surge below this and only for 1-2 seconds each time, then the 12/500 specification is within the operational range. The 12/800 would of course be a suitable candidate and probably more so – however it will still go into the overload situation and is twice the price of the 12/500.
Given that the 12/500 inverter will be running at under 10% of its capacity (35W draw on a 400W inverter), I think it is the best option to power a Fridge.
So with the cost of the Victron inverter added into the equation, our savings of AC Fridge vs DC Fridge has now dropped from the £500+ to around a £350 saving – no small change I think you would agree!
If you opted for the 45L AC Fridge option, the saving would be less as the 45L Inverter Fridge is £100 less than the 93L model, but the Waeco CRX-500 is around £200 less than the CRX-80. But you would still be looking at a saving of £250 – or 50% less than the traditional option.
I have had the AC Fridge running in Clarence, my Camperbus Conversion, since the end of October 2017, so it has been running throughout the long winter we have had in 2017/2018, and also through the UK Heatwave in June/July 2018 and has performed flawlessly throughout that time. The power usage has hardly fluctuated with the higher temperatures (and higher temps are invariably accompanied by brighter days, so the Solar Harvesting would have compensated anyway) so as a viable solution I think the AC Domestic Fridge (make sure it is the right AC fridge though) is easily a match in a campervan to the traditional DC Compressor Fridge.
If you would like more information about installing an AC Fridge in your Campervan, Motorhome or Caravan, please contact Wildebus. If you want us to supply a turn-key solution for you to install, or even do the installation itself, feel free to contact us for a quote.