Think the problem in a caravan is often limited 12v storage. Gas is easier to store.
My brother uses his caravan a lot. And seems to have endless problems with fridges. Usually the heating element - gas seems to be more reliable. Do they use the same heating element for 12v and 240v (via the caravan 12v PS)?
^ This
No, separate heaters, with dire warnings to not use both at once
Avpx
Perhaps I only go away for a few days at a time, and buy any food when I like, where I like.
If you travel for months keeping the same food frozen in your freezer, then perhaps I can see your point.
Ice for your drinks? ;)
We have a boat, basically the same issues as a caravan. We've had a few boats in different places over the years.
Once upon a time absorption fridges were the best solution because they could run on gas and, though inefficient compared with compressor fridges were OK because gas was cheap. Plus you can store a lot of energy (and thus fridge running time) in a small space compared with batteries.
However with increasing gas prices and more effecient (and cheaper) inverters we now use a cheap standard domestic fridge running it on an inverter when we are away from mains power.
It's a cheaper solution than a 12v compressor fridge because 12v fridges are very expensive compared with a standard 240v fridge.
Not in the Thetfords, one of the common makes. There different elements for
12V and 240V, they fit into a cylinder like arrangement which is also like a chimney for the gas burner, the whole assembly is wrapped in glass fibre like insulation. A coolant pipe runs through it.
My understanding is that the 12 V element is not fed via a thermostat, because of the problem of switching dc cleanly without introducing unacceptable hysteresis.
This is generally a workable compromise, on the basis that 12 V is only used whilst on the move.
Chris
The freezers aren?t huge - I forget the capacity but around size of a single freezer drawer.
We tend to by most food as we need it but we like to have a some meals we?ve made ahead and frozen, mainly for days we?ve been travelling etc. I am also a fan of soup, make homemade soup in bulk. When I don?t fancy a big meal, it is perfect.
I?m not sure about that.
Some claim on 12 V 3 way fridges / freezes don?t get cooler, they just stay cool on 12v. That isn?t out experience. We were total beginners in 2011 and, on our first trip, ( only to a site 90 mins or so away) I popped some water in the ice cube tray. It certainly froze during the trip. That fridge was a more basic one. Maybe the older ones. The newer ones are more sophisticated.
A fridge freezer with a small freezer box will consume 50% more energy than a standard fridge.
By way of example:
I suppose I'm more familiar with live-aboard boats where solar isn't as effective as one might hope!
In what way?
A lot depends upon ambient temperature. Without a thermostat, in cool weather conditions over-cooling the fridge is a distinct possibility.
I gather a potential problem with the latest designs is that even when being operated on gas, the battery supply is still required for the controls.
Chris
We have a boat in Northern France, it has three full size (about 280 watt nominal) solar panels. In the summer months we can run our standard under counter domestic fridge (with a small freezer compartment) via an inverter. In the winter there's not enough sun.
I'd guess with more modern panels (now around 400 watt each I believe) and a more efficient fridge we might get away with all the year round.
Interesting.
While I?ve bought and installed a 12v compressor fridge / freezer - which cost a fortune- I have since looked in more detail at the inverter / domestic approach.
A comparable domestic fridge freezer - a bit smaller but the nearest I could find quickly- claims to consume roughly the same kWhr per year (no running power given).
My 12v one takes about 3A at 13.8v. The makers claim you can run it for about 3 days off 2x 95Ahr batteries to 50% so consuming 95Ahr in 3 days @
25 degrees C. To maintain the batteries you?d need about 30 Ahr / day. Assuming 5 hours sun, that is only 5 A. Allow a bit for losses etc, say 7A.That should be well within the capability of 280W of solar panels.
As a cross check. A 250W panel should produce 30kwhr / month ( online number). About 1kwh / day.
The quoted consumption for my fridge is under 0.5kwhr/day, annual about the same as a similar (slightly smaller) domestic one ( around 160kWhr).
It doesn?t seem to be your fridge that is the problem, even allowing for inverter losses.
I'm struggling to believe those numbers. My understanding of your 3A is that's the average current taken, or if the motor is variable speed that may be the continuous running current under normal conditions.
Can you provide the model details?
Some compressor fridges have a block of some substance that is cooled when power is available and keeps the fridge cold when it isn't. Also I keep one of those freezer packs in the freezer compartment and put it in the fridge part when off grid. When off grid I cut the power to the fridge for the first 24 hours. It stays cold.
My 24V fridge draws 1.5A but it is only running for about a third of the time in normal weather.
It's better to use fridges designed for marine use than for caravan use.
Bill
Thetford T2160
The domestic one was some cheapie from Curry?s, about £180, and roughly the same size - made in China.
I measured the current of the 12v one while running off a 13.8 v supply. It is the current while the compressor is running, I measured it while in my garage testing before fitting. Once the fridge was down to temp, the current was naff all. I didn?t run it long enough ( or full of food) to get a duty cycle but others say they run about 30% of the time. That is consistent with my measurements and the claimed consumption.
Limited testing I agree but certainly looking good.
0.55kWh => an average of 1.9A at 12V over 24hours. If you say it is on for 30% of the time then the running current is 1.9 x 1/.3 = 6.3A 0.55kWh sounds about right for a modern fridge freezer ~ 200kWh per year.
So no more efficient than a current 230V fridge freezer.
Mine uses 1.5A at 24V when it's running.
Bill
17A
Bill
Mine used 1.2kg of ammonia as the working fluid. They seldom leak, but if they do one can kill a large number of people. I vaguely remember a report done on them concluding that the small number of them in houses constituted a serious danger to life. I got rid of mine.
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