Being Sunday no one open so hoping an expert here.
12V fridge (no gas) with Mobitronics rectifier almost new.
Had to replace solar reg after Easter as it faulted, voltage all over the place, mainly tracking battery voltage not bulk or absorption stages.
ANYWAY fridge runs on 24V DC via Mobitronics when on 240V.
PROBLEM is fridge voltage drop 2.5V when on 12v alone and trying to start,,,,, so suspect low voltage trip out of fridge as it tries to restart about 60 secs later.
Connected fridge direct to battery and bypassed Solar controller and load and Mobitronics rectifier.
QUESTION for those familiar with BD50 operation - do you think the fridge controller is the problem, ie works on 24V but not on 12V ?????
Peter_n_Margaret said
01:36 PM May 5, 2019
Maybe?
The BD35 compressor will run down to about 10V though. Don't know anything about the Mobitronics. Why not run it from the 12V house battery?
Measure the voltage at the fridge as it tries to start.
Cheers,
Peter
Baz421 said
02:02 PM May 6, 2019
Yes drops to 10v,,,,,at fridge. Battery 12.5v before fridge tries to start
Whenarewethere said
03:33 PM May 6, 2019
The Waeco 28L fridge I have has a compressor actually not much smaller than the larger fridges. Voltage drops about 0.5 volts when running off 78AH of 12 volt batteries only.
Dropping 2.5 volts I think you have a battery problem.
When my battery is fully charged the current is about 3.8 amps (about half the rated current in the manual). The fridge draws less current when the battery is low, about 2.5 amps.
Your 50L fridge is only drawing about 4amps when running, not the, about 6.5 to 7amps rated current in the manual.
I've done endless testing with a clamp meter & also have an inline amp meter so have a pretty good feel for what the fridge uses.
What gauge wire are you using, & how many metres, there & back, ie + & - !
Baz421 said
04:50 PM May 6, 2019
Whenarewethere wrote:
The Waeco 28L fridge I have has a compressor actually not much smaller than the larger fridges. Voltage drops about 0.5 volts when running off 78AH of 12 volt batteries only.
Dropping 2.5 volts I think you have a battery problem.
When my battery is fully charged the current is about 3.8 amps (about half the rated current in the manual). The fridge draws less current when the battery is low, about 2.5 amps.
Your 50L fridge is only drawing about 4amps when running, not the, about 6.5 to 7amps rated current in the manual.
I've done endless testing with a clamp meter & also have an inline amp meter so have a pretty good feel for what the fridge uses.
What gauge wire are you using, & how many metres, there & back, ie + & - !
Thanks for post. problem is not battery,,, as solar and 240v charger provide constant voltage at fridge. Turn on more load and no voltage drop,,,just damn fridge.
Companies useless here in Western Melb , all too hard ,,, going to Shepparton tomorrow,,, found a fridgie who is experienced with 12v(after 3 attempts - at least they were honest enough and said they were 240v guys not enough experience with 12v controllers). Cheers
Peter_n_Margaret said
06:59 PM May 6, 2019
Baz421 wrote:
Yes drops to 10v,,,,,at fridge. Battery 12.5v before fridge tries to start
If the battery stays at 12.5V at this time, it is almost certain that your cables are too small.
Cheers,
Peter
DeBe said
07:25 PM May 6, 2019
Yes drops to 10v,,,,,at fridge. Battery 12.5v before fridge tries to start . If the voltage at the fridge is 12.5V then drops when fridge trys to start, then the wiring is too small.
-- Edited by DeBe on Monday 6th of May 2019 07:26:30 PM
Whenarewethere said
07:32 PM May 6, 2019
I'm using 6awg & only have a short run loosing about 0.2 volts. I upgraded the wiring within the fridge from 16awg to 12awg saving about 0.17 volts. You will loose about 0.2 volts from the standard Waeco 1.5 metre lead, so cut it as short as possible as in the photo. I put a circuit breaker in the fridge, not shown in this photo.
Did similar to above . Used longer cable with Anderson plugs, twice the wire size that came with fridge as the cable was 4m long . We move it around in various locations . Originally I had extension on original lead . Too much voltage drop., Intersting the V difference at board & fridge . In one case recently it was defective fuse !! One has to be observant!! Jack or Jill of all trades !
Brody said
05:51 PM May 7, 2019
Hi guys slightly off topic, but in regard to the danfoss control unit- ive recently replaced the thermistor in my waeco cf-35. Im now getting three flashes error code so im thinking the control unit could be gone. Has anyone got a good photo showing all of the wires connecting to the danfoss unit (pref cf-35) i forgot to take one before! and want to be sure ive reconnected correctly before more troubleshooting. Many Thanks
Brody
Baz421 said
06:02 PM May 7, 2019
Peter_n_Margaret wrote:
Baz421 wrote:
Yes drops to 10v,,,,,at fridge. Battery 12.5v before fridge tries to start
If the battery stays at 12.5V at this time, it is almost certain that your cables are too small.
Cheers,
Peter
Same wire for 12 years now,,, never had this problem. Just had fridgie put new controller in and test,,, not controller. He said wiring good for the job.
-- Edited by Baz421 on Tuesday 7th of May 2019 06:02:33 PM
Baz421 said
06:07 PM May 7, 2019
Aus-Kiwi wrote:
Did similar to above . Used longer cable with Anderson plugs, twice the wire size that came with fridge as the cable was 4m long . We move it around in various locations . Originally I had extension on original lead . Too much voltage drop., Intersting the V difference at board & fridge . In one case recently it was defective fuse !! One has to be observant!! Jack or Jill of all trades !
Yeh I took the fuse out of the equation too no different. Still scratching my head, why OK for 12 years and now a problem.
Cleaned terminals on fridge controller traced wiring all looks good, clean tight connections
Thinking the earth may be a problem,, as I've concentrated on + wire so far.
Fridgie couldn't find a problem so I go backwards from fridge with earth wiring.
Cheers
Baz421 said
06:09 PM May 7, 2019
Brody wrote:
Hi guys slightly off topic, but in regard to the danfoss control unit- ive recently replaced the thermistor in my waeco cf-35. Im now getting three flashes error code so im thinking the control unit could be gone. Has anyone got a good photo showing all of the wires connecting to the danfoss unit (pref cf-35) i forgot to take one before! and want to be sure ive reconnected correctly before more troubleshooting. Many Thanks Brody
Danfoss manuals are online, easy to find
.
Peter_n_Margaret said
07:34 PM May 7, 2019
Look for some other high resistance in the lines. Is there anything warm?
Cheers,
Peter
Baz421 said
07:49 PM May 7, 2019
Peter_n_Margaret wrote:
Look for some other high resistance in the lines. Is there anything warm? Cheers, Peter
Thanks peter am doing that,,, maybe do again I guess. What do you think chances of an earth problem.
Peter_n_Margaret said
09:10 PM May 7, 2019
Baz421 wrote:
Thanks peter am doing that,,, maybe do again I guess. What do you think chances of an earth problem.
A resistance in the earth has the same effect as a resistance in the active cable.
You could experiment by running new heavy temporary cables, both +ve and -ve (one at a time, then both together) to check what the effect is.
Cheers,
Peter
Baz421 said
05:44 PM May 8, 2019
Peter_n_Margaret wrote:
Baz421 wrote:
Thanks peter am doing that,,, maybe do again I guess. What do you think chances of an earth problem.
A resistance in the earth has the same effect as a resistance in the active cable.
You could experiment by running new heavy temporary cables, both +ve and -ve (one at a time, then both together) to check what the effect is.
Cheers,
Peter
Yes been doing that,, I was alluding to a earth problem between batteries - solar controller - and fridge.
Anyway direct wired fridge to existing solar + and - load connections AT VAN ie the common connections,, same result.
I'm not sure if I have the right compressor controller as the pdf download says the 600 is not for my compressor BUT I can't fully understand the tech stuff.
Thanks for assistance Peter
Aus-Kiwi said
11:07 AM May 9, 2019
Run a temp lead back to neg battery terminal ? Jumper leads etc ?? I found with my spot lights .. The earth or - was restrictive . I just earthed at last light . Fixed ., In this case with HID the start up current- voltage drop the HID light at the end of circuit wouldnt start !! Is the frame or chassis the earth ? This is possibly the issue here IF theres other load on circuit ?
Baz421 said
08:29 PM May 9, 2019
Mysteriously,,, solar controller load on/off switch seems to be working now, don't know why but voltage drop today was 0.2v.
Previous unit that failed at Easter wouldn't charge at all load or battery.
Maybe there is a problem with load on/off function at the controller.
Thanks for all ideas,,,, see if it's working OK in the morning xxxxx fingers.
Cheers baz
DeBe said
03:36 PM May 10, 2019
I personaly would not be using an internal load switch on a Solar regulator to run a fridge.
T1 Terry said
05:43 PM May 10, 2019
If you use the load terminals to drive a relay rather than trying to power the fridge through the controllers transistor you will have more luck. The stall current required to start up the 12v compressor can be quite high, only short term load but transistors don't understand short term, only peak load and after that the fail. I've seen a Plasmatronics 20/20 burn out the 20 amp load transistor running a 225ltr Waeco fridge, the numbers don't add up but the transistor and circuit board said it couldn't handle it.
T1 Terry
Baz421 said
04:45 PM May 12, 2019
Thanks guys I'll look to change fridge off load. Cheers
Peter_n_Margaret said
05:42 PM May 12, 2019
DeBe wrote:
I personaly would not be using an internal load switch on a Solar regulator to run a fridge.
Depends on the regulator.
I have two Danfoss BD35 compressor fridge units (one fridge and one freezer) that have been running directly from the PL60 load terminals successfully for 14 years.
Cheers,
Peter
T1 Terry said
03:19 PM May 13, 2019
Peter_n_Margaret wrote:
DeBe wrote:
I personaly would not be using an internal load switch on a Solar regulator to run a fridge.
Depends on the regulator.
I have two Danfoss BD35 compressor fridge units (one fridge and one freezer) that have been running directly from the PL60 load terminals successfully for 14 years.
Cheers,
Peter
PL60 has a load current rating of 30 amps, the newer Pl80 load rating is 40 amps. The PL20 has a load rating of 20 amps, yet the PL40 is only rated at 7 amps, so the actual rating of the load circuit is very important. The stalled rotor current for a BD35 would be a lot smaller than the stalled rotor current for the BD50. Much easier to shift the load to a relay, cheap and easy to replace, not like the circuit board and transistor in the solar controller ....
T1 Terry
KevKim37 said
02:37 PM May 18, 2019
Hi Baz421,
Did you find the voltage drop problem.
If not, my advice is too Turf the useless, overpriced Mobitronic auto changeover unit.
These have too much internal voltage drop/resistance problems to run the 12 volt side.
Test your input and output volts at the unit terminals.
I fitted heavier gauge wire to our 220 litre Waeco Coolmatic compressor fridge 7 years ago and it still didn't correct the problem.
On further testing found approx 2 volt drop at the Mobitronic output terminals.
I bypassed it and no more problems.
I then purchased a Jaycar Powertech 12 volt/12.5 amp Power Supply unit for $119 and it has worked great ever since on 240 volt mains.
The only problem with this unit is that it isn't an Auto Changeover unit.
I've had 3 of the Mobitronic fail in the early years.
Cheers Kev. (2K's from Home).
-- Edited by KevKim37 on Saturday 18th of May 2019 02:38:10 PM
-- Edited by KevKim37 on Saturday 18th of May 2019 02:39:03 PM
Thanks Kev,,,, voltage drop is still 0.2v,,,,, the load switch seemed to be the problem on the Powertech solar controller,,, stays on load ok now. No voltage drop across Mobitronics.
Being Sunday no one open so hoping an expert here.
12V fridge (no gas) with Mobitronics rectifier almost new.
Had to replace solar reg after Easter as it faulted, voltage all over the place, mainly tracking battery voltage not bulk or absorption stages.
ANYWAY fridge runs on 24V DC via Mobitronics when on 240V.
PROBLEM is fridge voltage drop 2.5V when on 12v alone and trying to start,,,,, so suspect low voltage trip out of fridge as it tries to restart about 60 secs later.
Connected fridge direct to battery and bypassed Solar controller and load and Mobitronics rectifier.
QUESTION for those familiar with BD50 operation - do you think the fridge controller is the problem, ie works on 24V but not on 12V ?????
The BD35 compressor will run down to about 10V though. Don't know anything about the Mobitronics. Why not run it from the 12V house battery?
Measure the voltage at the fridge as it tries to start.
Cheers,
Peter
The Waeco 28L fridge I have has a compressor actually not much smaller than the larger fridges. Voltage drops about 0.5 volts when running off 78AH of 12 volt batteries only.
Dropping 2.5 volts I think you have a battery problem.
When my battery is fully charged the current is about 3.8 amps (about half the rated current in the manual). The fridge draws less current when the battery is low, about 2.5 amps.
Your 50L fridge is only drawing about 4amps when running, not the, about 6.5 to 7amps rated current in the manual.
I've done endless testing with a clamp meter & also have an inline amp meter so have a pretty good feel for what the fridge uses.
What gauge wire are you using, & how many metres, there & back, ie + & - !
Thanks for post. problem is not battery,,, as solar and 240v charger provide constant voltage at fridge. Turn on more load and no voltage drop,,,just damn fridge.
Companies useless here in Western Melb , all too hard ,,, going to Shepparton tomorrow,,, found a fridgie who is experienced with 12v(after 3 attempts - at least they were honest enough and said they were 240v guys not enough experience with 12v controllers). Cheers
If the battery stays at 12.5V at this time, it is almost certain that your cables are too small.
Cheers,
Peter
Yes drops to 10v,,,,,at fridge. Battery 12.5v before fridge tries to start . If the voltage at the fridge is 12.5V then drops when fridge trys to start, then the wiring is too small.
-- Edited by DeBe on Monday 6th of May 2019 07:26:30 PM
I'm using 6awg & only have a short run loosing about 0.2 volts. I upgraded the wiring within the fridge from 16awg to 12awg saving about 0.17 volts. You will loose about 0.2 volts from the standard Waeco 1.5 metre lead, so cut it as short as possible as in the photo. I put a circuit breaker in the fridge, not shown in this photo.
Same wire for 12 years now,,, never had this problem. Just had fridgie put new controller in and test,,, not controller. He said wiring good for the job.
-- Edited by Baz421 on Tuesday 7th of May 2019 06:02:33 PM
Yeh I took the fuse out of the equation too no different. Still scratching my head, why OK for 12 years and now a problem.
Cleaned terminals on fridge controller traced wiring all looks good, clean tight connections
Thinking the earth may be a problem,, as I've concentrated on + wire so far.
Fridgie couldn't find a problem so I go backwards from fridge with earth wiring.
Cheers
Danfoss manuals are online, easy to find
.
Cheers,
Peter
Thanks peter am doing that,,, maybe do again I guess. What do you think chances of an earth problem.
A resistance in the earth has the same effect as a resistance in the active cable.
You could experiment by running new heavy temporary cables, both +ve and -ve (one at a time, then both together) to check what the effect is.
Cheers,
Peter
Yes been doing that,, I was alluding to a earth problem between batteries - solar controller - and fridge.
Anyway direct wired fridge to existing solar + and - load connections AT VAN ie the common connections,, same result.
I'm not sure if I have the right compressor controller as the pdf download says the 600 is not for my compressor BUT I can't fully understand the tech stuff.
Thanks for assistance Peter
Mysteriously,,, solar controller load on/off switch seems to be working now, don't know why but voltage drop today was 0.2v.
Previous unit that failed at Easter wouldn't charge at all load or battery.
Maybe there is a problem with load on/off function at the controller.
Thanks for all ideas,,,, see if it's working OK in the morning xxxxx fingers.
Cheers baz
T1 Terry
Depends on the regulator.
I have two Danfoss BD35 compressor fridge units (one fridge and one freezer) that have been running directly from the PL60 load terminals successfully for 14 years.
Cheers,
Peter
PL60 has a load current rating of 30 amps, the newer Pl80 load rating is 40 amps. The PL20 has a load rating of 20 amps, yet the PL40 is only rated at 7 amps, so the actual rating of the load circuit is very important. The stalled rotor current for a BD35 would be a lot smaller than the stalled rotor current for the BD50. Much easier to shift the load to a relay, cheap and easy to replace, not like the circuit board and transistor in the solar controller ....
T1 Terry
Hi Baz421,
Did you find the voltage drop problem.
If not, my advice is too Turf the useless, overpriced Mobitronic auto changeover unit.
These have too much internal voltage drop/resistance problems to run the 12 volt side.
Test your input and output volts at the unit terminals.
I fitted heavier gauge wire to our 220 litre Waeco Coolmatic compressor fridge 7 years ago and it still didn't correct the problem.
On further testing found approx 2 volt drop at the Mobitronic output terminals.
I bypassed it and no more problems.
I then purchased a Jaycar Powertech 12 volt/12.5 amp Power Supply unit for $119 and it has worked great ever since on 240 volt mains.
The only problem with this unit is that it isn't an Auto Changeover unit.
I've had 3 of the Mobitronic fail in the early years.
Cheers Kev. (2K's from Home).
-- Edited by KevKim37 on Saturday 18th of May 2019 02:38:10 PM
-- Edited by KevKim37 on Saturday 18th of May 2019 02:39:03 PM