2-way fridge run from 240v by external transformer?

[badams]

Hi - wonder if anyone can help... I've been looking for a three-way fridge for my camper but they're more expensive and less available than two-way versions, of course.

I want to use hook-up when at sites which offer it (gas at those that don't) and then 12v to charge off main battery when on the road... so 3-way would seem best - BUT instead, is it possible / safe to install a transformer to step down the 230v hookup to 12v, effectively charging the leisure battery continuously and running the fridge that way? Then I could get a cheaper fridge and still benefit from using hookup. As far as I can see, it'd just mean that the transformer was outside the fridge rather than internal as with a 3-way - but could the battery cope with it and provide constant 12v supply for the fridge?

hope someone can help!
cheers, adam

[Louey]

if you get a good answer and a wiring diagram then can you pass it on please? possibly one for the wiki if it gets solved

[kevtherev]

this looks promising for small rectifiers

http://www.unipower-corp.com/Unipower_T ... elves.html

[badams]

thanks kevtherev - it does look promising. Useful to know... I just need to figure out which one i'd need.

[perro]

The two way fridge will draw about 7 to 9 amps depending on size when running on 12v thats quite a current draw easy to do if you want to use a step down transformer and a rectifier maplins will have all the bits you need . The connection is only two wires into the fridge .

A decent auto battery charger will do the job if you think about it

[SteveW]

I have 2 power supplies that I have used one is rated at 10A continuos and has no internal fan. This one gets way hot after a few hours and I would not loike to use over a longer period. I also have a 16A version with a internal fan. This is fine and keeps it's cool, the fan does get annoying after a while. Bearing in mind the price of these units I would think that if you did not have one for another use you would be better off putting the money towards a 3 way fridge.

PS the 240 volt does not go through a transformer on a 3 way there are 2 different heaters one for each 12v and 240v. Hope this helps.

[shepster]

Why not just run it on gas when you are camping? it doesn't cost that much.

[tonytech]

Remember that most 12 fridges dont have a thermostat so will get colder than necessary. I suppose you could build a simple thermostat circuit to switch the supply on and off.

T

[Louey]

Why not just run it on gas when you are camping? it doesn't cost that much.

I partly agree, but if you've paid for electric or it comes witha pitch then it makes sense to use it

[shepster]

Fair do's, it just seems like a load of hassle to me when you can simply 'flick the switch'. Each to his own though.

[badams]

thanks very much everyone - and esp SteveW for your tip about the noise of the fan / power units heating up etc. and tonytech for the point about thermostats - stuff I hadn't known / considered. It sounds like the amount of faff (and extra boxes of kit in the van) will outweigh any benefits, so I think when all is added up a 3way still does it best.

Now I just have to find one I guess - oh, and assuming the fridge has to vent out the side of the van, I suppose I have to cut a hole in the bodywork for a grille? ouch. Not something I'm going to do myself - anyone know someone in east anglia (norfolk best) who would do such a thing?

thanks, adam

[kevtherev]

Grills? No not entirely necessary some of the early campers and fridges have no grills just the flue vent.

Now in the winter the small amount of heat given off the heat exchangers is a bonus if it is allowed to rise into the cabin.

in the summer on a hot night I suppose a window open is the way to go.

My van has a vent in the floor, which allows the condensation to drip straight outside, preventing a rust trap. But also it does have one side vent

it depends on the size of your intended fridge I suppose. As the bigger they are the more ventilation or air movement they require to achieve the lower temperatures.

it freezes wine and beer overnight on gas No 3

[badams]

oh... so I may not have to hack about at my bodywork? brilliant!
It's a bit weird as my van has the usual unit with sink, hob and so on - including the grille in the bottom of the van for the sink waste and any gas to fall out of but it doesn't seem to have ever had a fridge, so I'm having to figure it out.

I figured it needed to vent the exhaust gases outside, though. So it's safe to vent it into the van, you think?

thanks for the bodywork-saving advice! adam

[kevtherev]

So it's safe to vent it into the van, you think?

safe to vent the heat from the exchanger yes..... as it is just warm air

[lloyd]

So it's safe to vent it into the van, you think?

safe to vent the heat from the exchanger yes..... as it is just warm air

but do need to have vent for CO when using gas...