Anyone Done the John Nixon Refrigeration Power Supply Project?

[Ken Krawford]

Last year I installed a 12VDC power supply to run my refrigeration when at the dock. 

When I arrived at the boat today I noticed that the refrigeration wasn't running.  After a bit of troubleshooting, I determined the the Adler Barbour unit had a blown fuse.  I replaced it and everything ran fine.  I then noticed that the red LED on the A/B controller was flashing indicating that the voltage was below 10.5 volts.  A quick check showed 13.4 volts to the A/B unit.   My compressor unit is in a location that is difficult to access so I don't know if this LED has been flashing since I installed the power supply or is something new.
Has anyone encountered the flashing LED that is using the power supply? 

[jmnpe]

Hi Ken,

Have you tried completely removing power from the A-B compressor for about 15 seconds and then re-applying power to see if the error light goes away?

I doubt that the power supply could have done anything to the compressor: it has built-in over-voltage clamping on the output.

Regards,

John

[Ken Krawford]

Hi John,

Thanks for the reply.  When I replaced the fuse, I turned off the A/B circuit breaker on the panel as well as the circuit breaker to the power supply.  IT was off for at least 10 minutes.  I failed to mention in my initial post that the LED only blinks when running from the power supply.  When it's running from the batteries, everything is ok.

Ken

[jmnpe]

Hi Ken,

Sounds like your power supply may have lost some output filtering and you are getting noise on the output voltage. For starters, look at the voltage going into the A/B from the power supply with your DVM in the AC Volts mode and see if you are getting measurable results in that mode. I you are, then measure the same feed point with the A/B powered from the batteries and compare the AC Voltage readings. If the difference is significant, you probably have a power supply issue.

I'll follow your posts and provide feedback.

John

[Ken Krawford]

John - thanks again for the info.  I ran the tests you suggested this weekend.  With the meter in AC mode I saw a reading that would bounce all over the place.  It would change so fast that I couldn't read it.  IIRC there were even a few negative readings.  I also noted that when I switched from battery to power supply, the compressor seemed to slow down a bit and labor even though the voltage was over 13VDC.
I'll await your reply about the goofy AC readings but I'm about ready to replace the power supply at this point.