Depends on the fridge type to a large degree, followed by battery capacity (and type - lead acid/lithium).
Absorption (3-way, gas/12v/240v) type fridges should NOT be running from 12v battery at all, they NEED to be powered from a running engine, due to their heavy power consumption. They can flatten a battery in a few hours.
The loosely termed 'fridge' of the Peltier/Thermoelectric Coolbox type are also unsuitable for running from 12v battery. Again they are heavy power consumers and usually without any thermostat, so constantly run flat out, again they can flatten a battery in hours OR many have battery protection circuits that switch them off when the battery voltage drops, that often means they only run for 15-30 mins before the battery voltage drops sufficiently to switch them off.
Compressor fridges are by far the most economical on power, they can run for days on a decent sized battery.
DO NOT run a fridge on gas on a ferry! The ferry companies ban it, you may get called to attend your vehicle and switch off the fridge if crew notice it, apart from all the safety issues.
Any type of fridge with a few ice blocks (or bottles/containers of frozen water) in it should be fine for 6-8 hours if the door is not opened after power cut off.
Been there, done that, nearly flattened the 12V leisure batteries or the van's battery with a thermo-electric coolbox, DOH!
Nowadays, I would only hook up the thermo-electric coolbox to the van's 12V socket and run it when I am driving, for it to switch to 240V mains power when I am on EHU on a site. It sits on the passenger seat nowadays.
My 80L Dometic fridge with a freezer compartment can run on 12V for a couple of days when the batteries are healthy. Hence I am having the batteries replaced this year as they cannot hold a charge sufficiently anymore.
DK
------------- Apple The Campervan - A Van For Work, Rest & Play!
- 2027: ? NL+DE+FR
- 2026: FR+DE
- 2025: 17/77
'24: 10/49; '23: 9/47;'22: 8/46; '21: 9/34
* Ex-tenter
* Treat life events like a dog: if you can't eat it, play with it or hump it, p1$$ on it and walk away!
I'd be tempted to just leave it be, if you are not opening the door of the fridge it should maintain its temperature pretty well.
You could always freeze cooling blocks and add these to the fridge when you board to add a bit of extra chill.
Unless you have something that must be kept in the fridge, then with the ban on dairy/meats etc. into France I wouldn't think you would have much in the fridge anyway.
Do you have a compressor fridge that runs off leisure battery in your motorhome ? If yes then yes you can. Leisure battery will charge up while you drive once off ferry.
Or do you have a 3 way fridge ? If you do then no. It will only run of engine battery while driving. It is not connected to leisure battery & cannot be due to high current drain.
If you want to run a Peltier type coolbox then yes you can as long as it runs from leisure battery & not engine battery or you will risk a non start when you are ready to drive off ferry.
If you have 3 way fridge then a couple of small bottles of frozen water should keep things cold during trip. Keep them frozen in freezer compartment then transfer them into fridge when you arrive at ferry port.
Quote: Originally posted by Swifty560 on 15/1/2026
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If you want to run a Peltier type coolbox then yes you can as long as it runs from leisure battery & not engine battery or you will risk a non start when you are ready to drive off ferry.
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The real and serious risk is that if it doesn't have an inbuilt battery protection feature, which will turn it off BEFORE battery voltage drops too low, it can discharge a battery (lead acid type) to permanently damaging levels! At best if it has battery protection it will only run for a shortish while, not hours unless you have a serious large battery set up!
Remember, lead acid batteries can only be safely discharged to around 50% of their stated capacity, and that capacity naturally declines with age/use. Typically a say 100Ah labelled battery may only have a REAL usable capacity of 20-30Ah or even less if approaching end of life!
Running a Peltier type coolbox/fridge solely off battery is less than ideal at the VERY best, but more likely to result in failure in under an hour.
I've a background in electrical/electronic engineering, I've got two coolboxes, one without battery protection and one with, I've done all the energy use calculations (AND suffered a flat car battery when careless!), and the battery protected one won't even start/keep running without the battery being on charge at the same time!
As I have mentioned already, nowadays, I only run my thermo-electric coolbox from the van's battery and only when I am driving, and store non-temperature sensitive items in there, such as beers and ciders.
DK
------------- Apple The Campervan - A Van For Work, Rest & Play!
- 2027: ? NL+DE+FR
- 2026: FR+DE
- 2025: 17/77
'24: 10/49; '23: 9/47;'22: 8/46; '21: 9/34
* Ex-tenter
* Treat life events like a dog: if you can't eat it, play with it or hump it, p1$$ on it and walk away!
Quote: Originally posted by tonybeech on 14/1/2026
hi we are travelling from newhaven to dieppe is it ok to leave the fridge on battery for 4hr thank you
No you are not supposed to take food from the UK into France and secondly a standard 3 way absorption fridge only runs on 12v when your engine is running and being directly powered from your alternator
I'm another one who got caught out many years ago. I had a cool-box running on my river cruiser. It was fine while the boat was running, the engine charging the batteries, but when I stopped and moored up for the night, within a short while my wife called out that she couldn't get any water. I checked out the electrical supply to the pump - nothing! Fuses were ok so I check the batteries themselves and they were completely flat. I'd had that set of batteries for a while and in less than two hours the cool-box had completely killed them. Not just flattened, they were wrecked! Fortunately I was only staying on the moorings for one night, and it was mid summer. We had to go to bed a bit earlier than planned as we only had a torch for lights. Good job the starter battery was separate, as it was needed in the morning and you can't push-start a boat.
Quote: Originally posted by neil and lena on 26/1/2026
Quote: Originally posted by tonybeech on 14/1/2026
hi we are travelling from newhaven to dieppe is it ok to leave the fridge on battery for 4hr thank you
No you are not supposed to take food from the UK into France and secondly a standard 3 way absorption fridge only runs on 12v when your engine is running and being directly powered from your alternator
Correct on both counts, well 'certain foodstuffs', basically meat or dairy or things containing them.
I haven't travelled to Europe since this was imposed (we used to take huge amounts to France to feed our camping group before this was imposed!), but have heard from multiple sources that no checks/penalties are imposed on personal foodstuffs - more blind eye turned than sanctioned! Not heard of a single case, and apart from this forum, I have feed back from thousands on a motor race supporters forum where around an estimated 60,000 Brits descend on the motor race event for one w/e in early June - golden opportunity if the authorities really wanted to throw their weight around! By contrast, motoring scrutiny is truly stepped up a notch or two, so it really is not a case of cant be asked to deal with the high volume!
We have always found that a couple of large bottles of frozen water in the fridge keep everything inside sufficiently cool as long as you are not opening the door (put the water bottles in the freezer at home for at least a couple of days to make sure they are really solid). If you can, run the fridge on mains for 24 hours at home before you leave to get the temperature down as quickly as possible and then switch to the battery while you are driving to keep it that way. When we get on the ferry we turn the fridge off and unplug the caravan from the car just to be on the safe side.
We have even done this on the long ferry to Santander and everything was still fine when we got to our site over 24 hours later.
Russell Hobbs RH4CLR1001 4L/6 Can Portable Mini Cooler & Warmer for Drinks,
I use one of these on longer ferry trips I have medicines that need to be kept below 8 degree c we run it while van is moving then take to cabin and connect to ships electrics
Quote: Originally posted by romany on 28/1/2026
Russell Hobbs RH4CLR1001 4L/6 Can Portable Mini Cooler & Warmer for Drinks,
I use one of these on longer ferry trips I have medicines that need to be kept below 8 degree c we run it while van is moving then take to cabin and connect to ships electrics
Unless you have a quality thermometer inside to confirm the temp, I wouldn't count on it storing your drugs reliably below 8C! Peltier/Thermoelectric device and only capable of around 18C below ambient after a VERY long cooling down period, OK for lightly chilled drinks but little else. Ambient would need to be below 24C for that to be relied on. ..... and with no thermostat, it could cool TOO COLD as well in chilly ambient, if drugs are sensitive to too cold temps as well!!!!
Quote: Originally posted by romany on 28/1/2026
Russell Hobbs RH4CLR1001 4L/6 Can Portable Mini Cooler & Warmer for Drinks,
I use one of these on longer ferry trips I have medicines that need to be kept below 8 degree c we run it while van is moving then take to cabin and connect to ships electrics
Unless you have a quality thermometer inside to confirm the temp, I wouldn't count on it storing your drugs reliably below 8C! Peltier/Thermoelectric device and only capable of around 18C below ambient after a VERY long cooling down period, OK for lightly chilled drinks but little else. Ambient would need to be below 24C for that to be relied on. ..... and with no thermostat, it could cool TOO COLD as well in chilly ambient, if drugs are sensitive to too cold temps as well!!!!
very true Monty which is why I have a digital thermometer inside it, never had a problem getting down to 8 degrees but have had to turn it off due tto getting to low
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Topic: fridge
via mobile 15/1/2026 at 10:46am
