help fixing a 12V portable freezer/fridge

[kevinnem]

Hello all , I have a 12v portable fridge / freezer , a knochoff brand I think from "Junyea" , it is the same as far as I can tell as the evakool bcd-60.
photos I found of the unit below.

https://thegreynomads.activeboard.co...60-2010-model/

It is not working, compressor not on, fan not on. there are no fuses.
I tried ( as per youtubes) to jump the T and C point together, and it worked for at least 10 mins, and I also plugged in the fan, and it started to work as well, then I pulled a few things off, and tried to re create that , and it has't worked since. The same jumping points now do not start the compressor. fan doesn't work, nothing.

I checked continuity from the 3 compressor pins to the chassis there is no ground short. I checked between the 3 pin for resistance, and it is kinda odd, I was getting .8,.8 and 1.0 , however, my multi meter might be wrong , as if I just touch the ends together I get 0.8 -- so maybe it is reading 0? this might be expected as it is just a bunch of winding, I think.

Lastly , I made a wire with an led in it, as some youtube suggest this can be used to get a error code out of the system, .. however, I hooked it between the C and D points ( as you would with a danfoss compressor, even though this is not that style) and I go nothing, I also reversed the wires, and still nothing from the led.

Anyway, I hopeing you might be able to provide some direction, ideas, ect .. I am not sure it is the controller, I would like to know if it is , . if it is , then I don't know how to replace it as I can't find any suppliers for these online ( though there appear to be plenty of danfoss ones, not sure they will work).

[Richard Kollmann]

There are a number of manufacturers producing these three coil compressors but I would not call yours as a knockoff, although it is of similar design to Danfoss BD compressors.

From what you reported I would rule out compressor unless your testing sent power directly into compressor. As far as field coil resistances from pin to pin it takes a good meter and clean connections to read resistance as low 3 ohms.

I would start with a couple simple tests before blaming control module:
With power turned off place jumper wire across C and T module terminals after disconnecting wires from these terminals. Also disconnect both fan wires from module F and small +. Now disconnect wire from P terminal.
Turn power on to refrigeration. If compressor runs use any kind of fan to disturb air around condenser coils.
Compressor does not run continuously or it runs and gets warm but no evaporator cooling turn off power and go to next test leaving test one without reconnecting wires to their normal position.
Test 2. Remove both power wires from at bottom of module and run new wiring with a 15 amp fuse in positive wire and connect both wires with correct polarity to module and a fully charged battery. If compressor runs and cools evaporator, problem is caused by faulty power wiring.

Module is the only item that can not be tested on the unit.

[kevinnem]

tried the jumper thing before I even posted, . and it worked for a moment but then never worked again...

I was going to take it to a electronic repair guy, I have used in the past, . but when I put it in the car , plugged it in to test it in the car, .. the damn thing worked ( after hours of messing around with it.)

Best I can tell the power souce I was using to get my 12 V DC from( 14.4) wasn't able to supply enough current to turn the compressor on , the one time it worked, maybe stuff was aligned just right .. and capacitors were full already or something, I don't know. I am assuming it was too weak a power supply -- that is to say it could supply the running load, but not the STARTING load.

[Richard Kollmann]

Originally Posted by kevinnem

tried the jumper thing before I even posted, . and it worked for a moment but then never worked again...

I was going to take it to a electronic repair guy, I have used in the past, . but when I put it in the car , plugged it in to test it in the car, .. the damn thing worked ( after hours of messing around with it.)

Best I can tell the power souce I was using to get my 12 V DC from( 14.4) wasn't able to supply enough current to turn the compressor on , the one time it worked, maybe stuff was aligned just right .. and capacitors were full already or something, I don't know. I am assuming it was too weak a power supply -- that is to say it could supply the running load, but not the STARTING load.

The newer brush-less direct current variable speed compressors will reject abnormalities produced by a dirty power source. The DC compressor’s electronic control module measures the quantity, quality and frequency of current before converting it into thee motor field coil's alternating pluses.
Dirty power can result in pulse frequency changes and low voltage spikes during compressor start up that can not be detected do to their very short durations with a voltmeter. You have already taken the third set in trouble shooting chart by eliminating the original power source so what is left is isolating and correcting boat’s wiring poor connections.

Another problem that confuses technicians is dirty power’s affect on module frequency pulse change in motor three phase coils resulting iin poor cooling with compressor running continuously.

[DeBe]

The Grey nomads link should help as i put the thread up. You may just find the problem you have is poor solder conections on the motor control board where the spade conectors solder on to the printed circuit board. That was what caused intermitent not working on that particular unit. Not something highly technical at all & is resonably common.