I’m installing a kitchen under the bed. A CD30 drawer fridge is perfect for this. It’s only 25cm high but holds 30 liters. Downside off course is the fact that you can’t store taller items standing up.
It’s a compressor fridge and energy efficient. The manual claims it uses 40 watts but some testing shows it only uses 2.2 amps @ 13,9V (about 30 watts) when the compressor and cooling fan are running with a small spike to 3 amps when the compressor kicks in. The requested temperature and the ambient temperature will determine how often the compressor and fan will run. The 110 watts solar panel and 110Ah AGM battery should provide enough power to run the fridge for 24 hours.
Changing the cut-off voltage
The fridge is equipped with a battery monitor which switches the compressor off to protect the battery when a low voltage is detected. It should switch off at 10.4 volts. and switch back on at 11.7 volts. Unfortunately, it’s insanely sensitive. I had it shut off at 12+ volts and start a turn off/turn on cycle.
Granted, the manual states you should use 4mm2 up to 8mm2 cables depending on length and I used 2.5mm2 which is plenty for the 3 amp load. Other people solved similar problems by beefing up the diameter. If you still have to install, use at least 4 mm2. I changed the cut-off voltage because I couldn’t run a new cable.
The Waeco manual doesn’t mention anything about changing or disabling the cut-off voltage. The fridge is equipped with a Secop 101N0650 controller board. The manual for this Secop controller board carries some interesting information. First of all, at 12 volts, 2.5mm2 cable should be enough for a 2.5meter run (page 6). Second, it documents how you can change the cut-off voltage using resistors or even a small piece of wire (page 10). The controller board is on the back of the fridge. By connecting a resistor with a specified value between terminals C and P, the resulting cut-off value will increase or decrease. I didn’t have any luck using resistors, but using 0 ohm (plain wire) worked perfectly. The cut-off value is now set to 9.6 volts and I haven’t had any issues with it for the last few months.
Word of caution: if you change the cut-off voltage, you are responsible for not running your battery down and possibly damaging it. Also, this change might void your warranty.
Ventilation and insulation
The unit doesn’t make much noise and most of it is coming from the fan. Considering the fridge will be under the bed, I expect it will be muffled to enough to not be a nuisance during the night. The ventilation is following a kind of “maze”. This will probably help with keeping the noise down. The fan will take air at floor level behind the water tanks. The warm air will be expelled underneath the sink.