I have been using a 2nd gen Engel 32lt refrigerator when camping. It's efficient but I feel some improvements could be made to make it even better. To adjust temperature you have a simple dial knob at the top with numbers 0 - 5 . I find setting 2 is a good for refrigerator (0 - 4 deg C) setting 4 or 5 is if I want to use it as a freezer (-12 - 20deg c).
In general this works fine but I do find there isn't any compensation for ambient temperature. For example on setting 2 I get between 0- 4 deg during the day but over night when the ambient temp drops I end up with 1/2 frozen milk. But If I was to set the nob at 1 or 1.5 and its hot during the day it might not be enough to keep things below 4 deg. Anyhow its manageable but you have to keep an check on it and fine tune the knob to make sure I am not over cooling then under cooling depending on ambient temp. This has to be wasting some energy to. I don't think the 0 - 5 settings on the nob relate to any actual thermostat setting or if the unit actually has one at all. Perhaps just a compressor cycle time ratio every hr or something like that.
The digital readout is nothing more that a simple a battery powered temperature gauge showing inside cabinet and has no control over the motor.
Just recently Engel came out with a 50th anniversary model fridge. It has all same features specs of the normal model other than the fancy gold paint. There was one notable addition..... (digital temperature control) I feel this is a valuable upgrade. Set the thermostat at 3 deg C and it will maintain it
I wont take credit for the following retrofit upgrade Idea as I did see an example selling online.
If I was to purchase a 12v digital thermostat unit . One with inbuilt relay trigger output. Then wire the 12v relays output to my refrigerator and place the temp probe in the fridge. Effectively interrupting the refrigerators 12v power cord. By setting the fridges knob to setting 5 (run compressor 100% of time) I would then Have digital control of temp and compressor cycling via the digital thermostat.
I can purchase the unit temp control unit for $15 online (That one is very popular unit and received a great review in a automotive magazine) . http://www.ebay.com.au/itm/DC-12V-LCD-Digital-Thermostat-Temperature-Control-Regulator-Controller-Aquarium-/290686773509?pt=AU_B_I_Electrical_Test_Equipment&hash=item43ae482905
The unit is programmable for set point delay's so the compressor doesn't cycle on,off,on,off around the set point.
Below is a link to the guy who is selling the units marketed towards eagle fridge users for $120 programmed and set in a nice component box with two plugs. I'm sure the components would be lucky to cost me $35 all up but I'm not 100% sure how much work he has put into programing the unit to cycle correctly - efficiently.
Link to ready made units being soldhttp://www.ebay.com.au/itm/Digital-Temperature-Control-Unit-12-volt-suit-Engel-Waeco-Camping-Fridge-Plug-CO-/221089974224?pt=AU_Car_Parts_Accessories&hash=item3379fd47d0
Anyhow I thought it might be worth me giving it a crack at building my own if I can save $90. I'm planing a 10,000km trip soon and hope to spend more time having fun than fiddling with the knobs to avoid frozen milk
Offgrid 2008, Selectronic PS1 6kw/48v inverter, x 2 Midnite solar classic 150 MPPT, 3960w NE PV 24 x 165w BP panels, 4200w NW PV 21 x 200w DAQO PV, 16x400ah lithium.