Hi, I know it looks like a no brainer to pay £500 for a 12v fridge when you can get a 230v version for a fraction of that.
To clarify 12 volt fridges run off 12 volt batteries, there is no inverter involved and they are by far the most efficient way of producing cold.
In my experience the boats with the most problems with battery power run a 230v fridge through an inverter set up. Others will be along to reasons why you should buy a 230v unit but on the whole they will be wrong !
A 12 volt fridge will take approx 4 amps out of your batteries 50% of the time, i.e. on / off cycle.
I have recently found Sterling inverters taking nearly 4 amps out of the batteries at idle.
Planning to live aboard, its a no brainer not to buy the 12 volt fridge.
From your stated proposed 230v usage you could reduce the size of the inverter to off set the cost of the 12 v fridge
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