12v freezer

[Sortie]

Mule. I had the pleasure of observing Mad Dog Mikes restoration of your boat. Everything on that vessel is to a standard of excellence that is beyond reproach. You got a heck of a boat. Sorry to hear of their problems. really nice folks.

Enjoy .
John

 

[Billylll]

Just an FYI on how these compressors work, they are all AC compressors, when running on 110VAC they simply use a step down transformer but it's still AC supplying the compressor. Once you switch to DC that's where a DC switching supply is used in other words a square wave inverter, different taps are used on the same transformer for the 12VDC switching supply/ inverter that supplies the compressor it's quasi AC.
Perhaps that's why they run better on 110VAC or at least the manufactures say so.
Bill

 

[ranger58sb]

Just an FYI on how these compressors work, they are all AC compressors, when running on 110VAC they simply use a step down transformer but it's still AC supplying the compressor. Once you switch to DC that's where a DC switching supply is used in other words a square wave inverter, different taps are used on the same transformer for the 12VDC switching supply/ inverter that supplies the compressor it's quasi AC.
Perhaps that's why they run better on 110VAC or at least the manufactures say so.
Bill

Not sure I can relate what you're saying to what NovaKool told me, Bill.

Their tech said it's a DC compressor in ours. If provided AC, that's converted to DC first (as with a laptop, cell phone charger, whatever)... so the compressor always runs on DC, no matter what the original source.

??

FWIW, we did also touch on the slight inefficiency that would be introduced with an inverter: changing DC to AC with an inverter, and then converting it back to DC during the fridge's power supply process. I don't know if that would be a big deal (don't have an inverter, haven't studied), assuming the inverter is doing other useful work at the same time anyway...

-Chris

 

[Billylll]

Not sure I can relate what you're saying to what NovaKool told me, Bill.

Their tech said it's a DC compressor in ours. If provided AC, that's converted to DC first (as with a laptop, cell phone charger, whatever)... so the compressor always runs on DC, no matter what the original source.

??

-Chris

That's what I originally thought until I helped a few other boaters with Dometic frig/ freezer repairs.
Bill

 

[ranger58sb]

That's what I originally thought until I helped a few other boaters with Dometic frig/ freezer repairs.
Bill

Ours aren't Dometic.

-Chris

 

[Billylll]

Thanks Chris, I just haven't seen a DC compressor yet. It might be possible that the units shown (thread starter) don't use compressors and maybe these units use Thermo-Electric (TE) module technology instead?
Bill

 

[ranger58sb]

Bill, here's from the "Installation and Troubleshooting Manual (2005)":

All Nova Kool units are supplied with the silent and efficient BD
series variable speed compressors from Danfoss. Nova Kool has supplied your
unit preset at the optimum speed for most “normal” applications. The speed is
controlled by a resistor in the thermostat
circuit. 0 ohms (no resistor) runs the
compressor on its slowest speed, a 1523 ohm
resistor will provide you with the fastest
speed. The slower the speed, the lower the
amp draw, and the lower the capacity. The
chart provides four examples, the resistance​

must be between 0 ohms and 1523ohms.


FWIW, there's another statement about cooling:

AC/DC units cool at the same rate​

on DC as on AC.



-Chris

 

[psneeld]

DC 12V 24V Refrigeration Compressor 134a QDZH30G New in Box | eBay

DC 12v - 24v refrigeration compressor~134A~QDZH30G~NEW IN BOX

 

[Wxx3]

If it's a Danfoss 35 or 50 compressor, it's 12/24 volts.

Most of the Italian manufacturers use this. It's what I have in my Vitrifrigo, which I love by the way.

http://www.ra.danfoss.com/Technical...N0210-20-40_0300-20_08-2011_dehcei100b602.pdf

Also as Bay Pelican mentioned, my AC wiring is such that the inverter only runs a few necessary 120 v appliances when not plugged into shore power or Genny.

 

[Billylll]

I stand corrected thanks for the documentation on the DC Danfoss compressors.
Thanks all,
Bill

 

[Mule]

Here is a link that does the summary of various refer systems vs Engle. Notice the start amps on piston compressors...unless you are on a super yacht these low draw units are the way to go. I have a new mr40 for sale, still in box, never fired up, reason for selling, I need a SR70 for the new boat. Currently using another mr40 and a mt35. I have a Dometic that I may sell also so as to have 2 SR 70 built refrigerators. Currently I have a frig-freezer that pulls almost as much after inversion as all of the Engles combined. I have been using my older mr40 for 2 years and I really like it...obviously since I am adding to the collection.
ENGEL USA - AC/DC FRIDGE/FREEZERS | PERFORMANCE COOLERS - - Fridge/Freezer Features