AUTOfridges - setting the fridge up for voltage cutout

[nicbeer]

hey all,

i have a autofridge


http://www.energymatters.com.au/autofri ... p-601.html

and wondering whats the best voltage to allow the battery to get to.

i have dual batteries (twin 520cca AC delkors) not deep cycle.

at the moment i can run fridge till it cuts out and still start the zook of that battery. it has a danfoss controller inside i can adjust to a certain amount.

[-Scott-]

I've never measured where my autofridge cuts out, but I run it through another low-voltage cutout that I installed (and adjusted) before I bought the fridge. The fridge cuts out before my cutout does, so I'm happy with where mine is set - if anything, I would set it lower, but mine runs off a second battery (so starting isn't an issue) and the existing setting hasn't caused any issues.

[nicbeer]

what model do u have scott?

i have one of the early 39L R12 ones i beleive. with an updated danfoss that can run a fan and led for indicator.

not going as cold as it should also. need to get someone to look at it. maybe regas or more euetic juice

[-Scott-]

what model do u have scott?

Not sure of a model number. Bought it about mid 2005, 39 litre. It still has the lid hinged at the end, but I have the fan in the top and an internal "tray". My father and brother have older models without either.

Mine freezes too easily. Left to cycle on the lowest ('1') setting it will start to freeze stuff. When I rang to ask if this was normal, I was told it is, but the manufacturer also gave me instructions on how to adjust the thermostat - I adjusted it once (only vaguely recall the process) and it's now a little better - takes longer to freeze.

[Dominator]

Cheif you will want to be carefull how low you set the cut out. I know you are running dual battries but starting your car is not the reason they have voltage cut outs. As your voltage drops the current your fridge draws increases. V=I/R. If your voltage gets to low you can do damage to your compressor windings or pc board. I would suggest the cut out being no less than 10.5 volts at the fridge, anylower and you may risk doing damage in the long run.

Also, i am not sure how the autofridge's work but if it runs off a compressor you usualy wont have a eutetic solution, (i could be wrong with this particualar brand) and it should only ever need a re gas it it has a leak. R12 is nearly impossible to get a hold of these days, unless you know someone, so it will need to be retrofit to R134A.

Hope that helps.

[nicbeer]

Cheif you will want to be carefull how low you set the cut out. I know you are running dual battries but starting your car is not the reason they have voltage cut outs. As your voltage drops the current your fridge draws increases. V=I/R. If your voltage gets to low you can do damage to your compressor windings or pc board. I would suggest the cut out being no less than 10.5 volts at the fridge, anylower and you may risk doing damage in the long run.

Also, i am not sure how the autofridge's work but if it runs off a compressor you usualy wont have a eutetic solution, (i could be wrong with this particualar brand) and it should only ever need a re gas it it has a leak. R12 is nearly impossible to get a hold of these days, unless you know someone, so it will need to be retrofit to R134A.

Hope that helps.

Yeps thats correct there is a Eutetic solution in there. its basically an icebox with a compressor in short. once cold the compressor can be turned off and it will stay cold a lot longer than a normal fridge. i can get R12 i believe off a mate.

thx on the Cutout, will have a look whats it set too now. i was thinking of what it can go down too on the compressor side. as Engels go down to stupid voltages as can kill batteries i have seen.

I found out that i can get a top up of the solution done for $80 as mine has a small crack in the bottom other than that works great.

[Dominator]

dont know if i would bother paying $80 for a top up solution. Most eutetics are not much different to engine coolant. I have repaired ice cream machines that use a eutetic solution and need to get down to -36C and we just used coolant and mixed it nice and rich.

[-Scott-]

I can't remember whether I read it or was told it when I rang, but the eutectic solution in the Autofridge is simply a salt solution in water. I don't know the concentration.

[Dominator]

if you want to make a salt and water solution just mix salt into the required amount of water. Keep adding salt untill it wont mix anymore. the actual meaning of eutetic is a salt/water mixture at its salt saturation point. ie, no more salt will mix with the water. also if you heat the water a little it will help the salt mix faster.

[-Scott-]

the actual meaning of eutetic is a salt/water mixture at its salt saturation point.

No.

http://www.businessdictionary.com/defin ... ectic.html

eutectic

Definition

Mixture of two or more components in such proportion that their combined melting point is the lowest attainable

The eutectic point of a salt solution isn't at saturation. But I doubt that a saturated solution would have a significant effect on the operation of the fridge - it's freezing point is still way below zero.

[poppywhite]

I see an energy matters sticka on that pic. If you bought from them phone and ask them they also sell all types of battery for alt power. most cranking batteries dont like much volt drop. If you plan to use a lot and dont have charging facilitys buy deep cycle battery it will be cheeeper than stuffing crank battery