Fridge on a timer (12v)

[springerdan]

Hi,

after years of living without a fridge onboard i have finally bit the bullet and acquired an old RM212 to experiment with. i was intending on running the fridge as follows:-

 

put a fair few of those cold block things into it.

as i leave for work in teh morning, put the fridge onto gas.

when i come home (anywhere between 6 and 7pm), take it off gas and place it into 240v mode as i run the generator to charge the batteries.

turn it off at 8pm and avoid opening the thing until the following morning.

after opening it in the evening, run the fridge on 12volt for a few minutes.

if i cruise, turn the thing on and take the power while its being made.

 

however the good woman and i have lost our bottle with gas, so to speak, so i was considering getting hold of a 12volt timer and asking that to run the fridge for the odd hour or half hour during the day and keeping some coldness that way until the usual 7 till 8 battery charging time when the fridge can run from the generator.

i have a 20 amp charger (and 10A for the lesser used bank) so i dont have many amps to be able to put in in my limited time available. i also only have a 220amp domestic battery bank and really would not want to run that down far.

 

currently () i dont really need to charge every day for more than around half an hour as i use very very little power which at this time of year the solar panels seem to help keep abreast of. i have 36watts of panels (dont ever see more than 12 watts come out of the whole set..) so i am hoping that with a little more solar, a 12v timer for the fridge and a little more battery charging i can avoid having the gas plumbed in - which i am not sure is even legit nowadays.

 

can you chaps and chapesses comment please on whether a timer running a fridge will be a waste of money and effort as i really dont have the funds available to buy a really efficient fridge and anything has to be better than nothing!

 

first topic/post so please be gentle!

 

~springerdan

[bottle]

Hi Dan and welcome.

 

The rm212 is a fridge designed for caravanning, it is a re-design because regulations were bought in many years ago that made it illegal to tow a caravan with the gas bottles turned on.

 

The fridge is basically designed to run on gas, it was then re-designed to have a 12volt element that replaced the gas flame when being towed, when using 12volt it will only maintain the temperature inside the fridge, it will not cool further.

 

The load when running on 12 volt is large and is continuous, not thermostatically controlled.

 

Later in its life, when 240v hook ups appeared on campsites the 240 volt option was added, this is thermostatically controlled.

 

Run it on gas and if you want to, run it on 240v (generator/landline) when available.

[sueb]

Hi,

after years of living without a fridge onboard i have finally bit the bullet and acquired an old RM212 to experiment with. i was intending on running the fridge as follows:-

 

put a fair few of those cold block things into it.

as i leave for work in teh morning, put the fridge onto gas.

when i come home (anywhere between 6 and 7pm), take it off gas and place it into 240v mode as i run the generator to charge the batteries.

turn it off at 8pm and avoid opening the thing until the following morning.

after opening it in the evening, run the fridge on 12volt for a few minutes.

if i cruise, turn the thing on and take the power while its being made.

 

however the good woman and i have lost our bottle with gas, so to speak, so i was considering getting hold of a 12volt timer and asking that to run the fridge for the odd hour or half hour during the day and keeping some coldness that way until the usual 7 till 8 battery charging time when the fridge can run from the generator.

i have a 20 amp charger (and 10A for the lesser used bank) so i dont have many amps to be able to put in in my limited time available. i also only have a 220amp domestic battery bank and really would not want to run that down far.

 

currently () i dont really need to charge every day for more than around half an hour as i use very very little power which at this time of year the solar panels seem to help keep abreast of. i have 36watts of panels (dont ever see more than 12 watts come out of the whole set..) so i am hoping that with a little more solar, a 12v timer for the fridge and a little more battery charging i can avoid having the gas plumbed in - which i am not sure is even legit nowadays.

 

can you chaps and chapesses comment please on whether a timer running a fridge will be a waste of money and effort as i really dont have the funds available to buy a really efficient fridge and anything has to be better than nothing!

 

first topic/post so please be gentle!

 

~springerdan

Buy a carbon monoxide alarm - preferably one with a digital display so you can see the numbers, then use it on gas. If no numbers are showing you have no problems. We bought our Kidde alarm from B&Q. We have run a gas fridge for 20 yrs.

Sue

[wonderdust]

What type are chargers are they? Can they not be left on peramantly, PowerPack mode, or even put the charger on a timer!

 

i have a 20 amp charger (and 10A for the lesser used bank) so i dont have many amps to be able to put in in my limited time available. i also only have a 220amp domestic battery bank and really would not want to run that down far.

~springerdan

Edited May 12, 2009 by wonderdust

[Gibbo]

The only way to run that type of fridge efficiently is on gas and then you have the problem of possible carbon monoxide poisoning. But let's not get into the probablities of that here.

 

Running on electricity they are horribly inefficient and drink electricity at about 8 to 10 times the rate of a compressor fridge for far less cooling.

 

You can't trick or fool the laws of physics. If you try to do so, by turning it off at certain times, it will warm up and it will use more power when you switch it back on again to get back to working temperature. If you manage to reduce the overall power consumption by means of this trick it simply means the fridge is warmer inside than it would otherwise have been.

 

The only time you can win using this trick of turning a fridge on and off manually is if you deliberately make the fridge far too cold when there is a surplus of electrical energy available (say when running the engine and the batteries are nearly full) then relying on the fridge remaining, on average, at about the right temperature.

 

Gibbo