12 Volt Thermo Electric Cool Box

[Halohodge]

When we travel from storage with the van we normally have a cool box on the back seat of the car as the internal fridge has not time to cool down. Next year I want to put my folding bikes on the back seat instead so I was wondering if I could put the cool box in the van at the front plugged into the 12 volt socket whilst towing, is this ok and has anybody done this

[JTQ]

If it is anything like a modern van the internal 12 volt system will not be "live" once coupled up and the towcar engine is running.

 

I am sure with the will and a bit of nous and DIY skills there is a work around this but is it worth it. If the produce is cold then IMO not much is going to warm up to levels of concern in the time scales involved with the inbuilt fridge getting going.

[Easy T]

Personally I would simply put a large ice pack or two on each shelf of the fridge and use that as a cool box.

[Jaydug]

JT is right! As soon as you start your engine the 12volt electrics in the van will switch off. If you have a 12volt socket in your boot or rear load area, you could get a two metre extension cable and run that to your van. I use a similar set up to power my caravan rear camera.

[Guest]

Depends on your van, mine does from the auxiliary supply which is part of the charge supply circuit, this would be the best circuit to use as it is normally on either a 15 or 20A fuse, Connecting a cigar type socket to the battery supply via a 10A fuse would be the best option.

[Halohodge]

Thanks for info, doesn't seem a very good idea, revert to plan B, only trouble is I hav`nt got a plan b

[maginnis]

What do you have that desperately needs keeping cold and how long is your journey likely to be?

 

I know everyone has a different way of caravanning but we never have anything that needs keeping ice cold - opposed to just cool in a cool bag with ice packs. But I shop on arrival, where as my friend takes everything with her - each to their own.

[Jaydug]

Before I set off for Spain each November I freeze solid two 1-ltr cartons of orange juice and a pint of milk at home. The day before I set off I buy quiches, pies and individual salad packs; as much as the BB dates will allow. Just prior to leaving home, the orange juice and milk go in the freezer compartment in the caravan with the other stuff filling the fridge. Thirty-six hours later the fridge is still cold and the 12volt supply takes over as I leave the ferry.

[Halohodge]

I know there are various options I can take, done it enough before, it just that we are taking the bikes to France (hopefully) next year again and with a long trip from the Midland then immediately onto a ferry to Caen, that`s quite a long time relying on freezer blocks, but `he ho` we shall endevour.

[ericmark]

Size matters, my home fridge/freezer can be off for 6 hours and all is still OK but the small extra one on top will only last 1 hour. The same applies to your cool box v caravan fridge the cool box needs power it will not last long without it. But the caravan fridge is much larger and even a couple of frozen bottles of water will keep it cool.

 

As to frozen bottles of water it is really surprising how long they take to defrost. I was cycling along a UK cycle route so one frozen bottle in ruck sack idea was it would still be cool 4 hours latter. Wrong still frozen solid, in fact 8 hours latter when returned to car still not melted. This was in a ruck sack not a fridge.

 

I think it was colder than I thought. It takes 2 days to freeze a bottle of water fully. But I had missed out one trip so this one had been in freezer for a week. Lucky found an ice cream van so did not need the water.

[Guest]

We take a coolbag with a 5litre bottle of frozen water on my mates boat when we go away - it's still very cold and there's a big lump of ice in it three days later.

 

A proper coolbox/cool bag will keep stuff cooler for a lot longer than an unpowered powered coolbox (if you can understand that).

 

A powered coolbox has a heat exchanger which conducts heat from the outside when it's not plugged in whereas a fridge or proper coolbox/bag doesn't actually have a heat conducting path to the outside.

 

Actually you can make a pretty good insulated coolbox just with slabs of polystyrene stuck together with duct tape - providing that it's sealed with no gaps it will keep stuff cool for a surprisingly long time if you put several ice packs in it.

[Brocher12]

You could always use a cigar lighter extension with the cable run direct from battery terminals of the caravan battery, this would also charge when the car is running if the towbar is wired fully. We have a fridge that produces ice cubes, we normally put these in to zip lok freezer bags over a few days before leaving. Then you can use what's left for topping of a nice brandy/Whisky etc once there.

[ericmark]

I could not believe how inefficient the Peltier, absorption and 12 volt compressor fridges/cool boxes and freezers are. For 230 volt single fuel units they have to comply with table 7 COMMISSION DELEGATED REGULATION (EU) No 1060/2010 of 28 September 2010, this stipulates the minimum standards and what label they will get A+, A++ or A+++ below A+ they can't even sell them.

 

But 12 volt and gas units don't come under the regulations and in the main would not even get a D energy rating. This is due to both the insulation used and the method of cooling. It would seem a 60 litre fridge D rated should be better than 342 kWh/annum but are more like 684 kWh/annum double the allowed amount.

 

Many also have no or little thermostatic control they just cool to approximate 30ºC below ambient, I know I have seen ice in my fridge where it has clearly gone below the normal 4~5ºC of a domestic model.

 

In real terms to keep food cool for a week or two on holiday it's good enough. But there is no way one can rely on food being kept cool enough using these Heath Robinson coolers. The fridges and coolers used to transport food are all compressor driven units.

 

The problem with any long trip is although one may have done it many times in 5 hours things do go wrong meaning still not at destination even after 10 hours. So what I do is buy food local and the fridge only means slight extension on use by date if not cooled and no way would I try to carry more than 2 days perishable food. If I want UK food then it's either freeze dried or cans.

 

I have selected items like Vesta freeze dried food not because I think they are really tasty but they are light and good for emergency when can't buy local food I like.

 

I lived in a touring caravan for some 5 years and I did consider using a mains fridge. However we also had frequent power cuts so one could never come home from work and be sure the food had not defrosted and re-frozen so pack of 10 beef burgers lasted 3 days then bin whatever was left.

[JTQ]

Our caravan's electronically managed absorption 'frigde freezer does have thermostatic control and would not thaw out from even a full day time length power cut. There is no danger of it defrosting and refreezing in the time periods we revisit it. I would be surprised if we did not notice it had defrosted itself we certainly would when getting out the icecreams, we could then make fact based decisions rather than keep dumping food just in case.

 

I don't have any doubt its efficiency re energy usage is very poor compared to a compressor based domestic fridge. However, we need to be able to use it on gas as frequently we don't have access to mains power, so efficiency is not an aspect that can dictate the situation we have to accept what technology offers a solution.

[beejay]

I could not believe how inefficient the Peltier, absorption and 12 volt compressor fridges/cool boxes and freezers are. For 230 volt single fuel units they have to comply with table 7 COMMISSION DELEGATED REGULATION (EU) No 1060/2010 of 28 September 2010, this stipulates the minimum standards and what label they will get A+, A++ or A+++ below A+ they can't even sell them.

 

 

 

 

Peltier v compressor type is not comparing like with like and there are no Peltier freezers

 

Most 12 volt compressor fridges are very efficient. Mine is an Engel (now Waeco) fridge/freezer which depending on the setting can be used as a fridge or a freezer. Getting down to -25C within two hours seems a good enough performance by any standard. The Sawafufi swing motor compressor is regarded as the best on the market and has a maximum consumrtion of 3 amps when running.

 

[ericmark]

You are correct, I had not seen this model before, both as fridge and freezer it is A++ and only £564. 07 a snip!

I had looked at a Waeco CRP-40 again very expensive and that worked out at energy class D, hardly seemed worth going for a compressor type with such a poor performance again £500 plus fitting bits.

[jetA1]

When we travel from storage with the van we normally have a cool box on the back seat of the car as the internal fridge has not time to cool down. Next year I want to put my folding bikes on the back seat instead so I was wondering if I could put the cool box in the van at the front plugged into the 12 volt socket whilst towing, is this ok and has anybody done this

 

According to the OP's profile he has Mondeo, I can't believe that even placing a couple of folding bikes in the back of the car there isn't room for the electric cool box.

 

I understand the 'need' for an (electric) cool box, we've travelled with one for the last 5 years, we have to carry insulin for one of our dogs (diabetic) which has to be stored at fridge temperature. We even have a 'small' electric cool box for when we go touring in our Triumph Spitfire.

Edited December 19, 2015 by jetA1