12V Compressor GE Refrigerator Review & 24V Hack
Hello everyone first-time poster so here goes nothing...
The GE GPV10 series is a 12VDC top-freezer/fridge with 9.8 c.f. capacity (shipping as 9.9 c.f.) rated for mobile and marine installations. It lists for about $1,050 US in black door or in stainless for +$50. It can be obtained from multiple online RV supply outlets for around $800 US in black [including shipping] which I found less expensive than the more recognized "RV" branded units. The country of origin is indicated as China.
This fridge replaced a 5 year old Norcold absorption type propane/AC unit in my camper. It easily fit both the width and depth of the Norcold's cabinet space but did require some adjustments vertically as it is a larger unit. The original outside fridge vent was replaced with a standard RV compartment door and the roof vent was sealed-off as external venting is not required by the manufacturer and also because the camper has 24/7 solar AC usually set at 72F. This fridge incorporates “skin” type coils located in the exterior sides for it's condenser [vs air-flow coils] hence the clearance requirements. Coil-cleaning/maintenance is not required.
IMO space-wise and in overall usefulness the GE is a superior unit to the Norcold but it does lack a few items for a RV installation. Fortunately there are some online RV part sites that now sell aftermarket top & bottom cabinet-face mounting brackets along with door “lock kits” made specifically for this model. They made the installation easier and doors travel-safe. Pics below.
The replaceable magnetic door seals seem to be of good quality but should be carefully adjusted using the slots in the door hinge brackets if changing the door swing or using the aforementioned aftermarket hinge-mount-sharing brackets. This step is unfortunately not in the manual and poor adjustment may lead to excessive frost build-up, the compressor running more than necessary or uneven wear on the seals.
This model is rated at 13.5 amps @ 12VDC. At 12.6 volts this copy averaged about 9.2 amps during initial start-up, gradually lowering to 5.2 amps for most of the cycle with roughly 6 amps (76 watts) being the average. The run time (duty cycle) is indicated on the product label at 32% @ 70F ambient and 57% @ 90F ambient (I assume this is without door openings). Hopefully this info will help others with estimating power requirements. I did not find any manufacturer specifications listing the minimum/maximum ambient temperature operating range. In addition to external fusing an external power switch or other means of disconnect is recommended as the “off” position on the thermostat stops the compressor but does not disconnect the phantom load of the controller or the internal lighting. I shook the compressor by hand while both running and off to simulate road vibrations and heard no ill “knocks or clunks” from over-extending the internal motor suspension that I've experienced with some AC fridge compressors under similar conditions.
The freezer section's evaporator is embedded in the four sides, not the back wall, and it's temperature seems pretty even throughout. The fresh-food evaporator is embedded in the back wall only so I plan food placement accordingly. I have experienced moderate frost build-up on the back wall. When the single rotary temperature control was set at “cold” it produced an average fresh compartment temperature of 36F and frozen of -10F. In the fresh compartment there is an internal drain basin for evaporator melt/runoff that empty’s into a plastic evaporation tray located above the compressor for the “partial-automatic” defrost function. There is no drain in the freezer and it's defrosting/melt removal is purely manual.
Now to the hack:
In the picture you'll notice the Wancool compressor and controller labeling indicates 12/24VDC compatibility. After a careful check I confirmed they were indeed of the dual-voltage variety, virtually identical to the Danfoss design, and that the only thing in the entire fridge that was 12 volt was the interior LED lighting! The compressor cooling fan receives regulated power from the controller making it and the purely mechanical thermostat 12/24V compatible.
A few easy measurements and calculations later resulted in a 200 ohm 2 watt resistor being added in series to the LED lighting circuit. It could have been added at the LED assembly itself or at the door switch but I opted to install it behind the easily accessible power input terminal strip. The input terminals have two red wires on the positive connection with one going to the compressor controller and the other going into the fridge's body to the door switch. The red wire to the door switch was cut, the resister inserted and heat-shrunk. For techies, the LED assembly measured 61 milliamps @ 12.6VDC. After conversion the circuit measured 60 milliamps @ 25.6VDC.
With this hack the fridge runs great on the camper's 25.6 volt lithium house system. After a few minutes of start-up current of around 4.6 amps it tapers to 2.6 amps where it remains for most of a duty cycle. Power consumption was identical to it's 12V operation at roughly 76 watts. I figure with a steady ambient of 72F over a 24 hour period it should consume about 600 watt-hours. This simple mod also saves about 6 to 12% of power by not having to run it through 24V-to-12V buck converter and lower cable loss.
Hopefully someone will find this info helpful when considering a lower-cost medium-capacity DC compressor-based fridge.
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