Turbocharging the Norcold N 180.3 3-Way Fridge (beefing up the 12 volt system)

dsatwork

I spent hours looking for resources that deal with the cooling issues that gas absorption refrigerators have. I found one guy (Val Rigoli an Aussie Go Figure) in particular that seemed to provide a complete discussion and even provides simple explanations of the science behind his ideas to improve any gas absorption refrigerator. http://www.fridge-and-solar.net/index.htm

 “The 12V side of these Gas-Electric fridges often has issues. It can be a huge problem with these fridges when folks run them on 12V. (The fridge is NOT at fault, it is a very common fitting fault!)” Aussie speak for they use too small of wires. You can find more on this page. http://www.fridge-and-solar.net/Gas-Fridge-Power-Problems.html

Essentially, he blames it all on the wiring being too small and I agree with him on this. The wiring from the Tab's battery is 10-gauge and makes its first stop at the cutoff switch. From the cutoff switch they continue with 0-gauge wire to the junction box. Then from the junction box, they run 14-gauge wire to the fridge. This is all totally within the Norcold spec for the N180.3 fridge, I double checked the installation manual. I just don't think it allows for maximum power draw. He points out in his article that you add resistance every time you add a junction along the way and he suggest running the ground directly back to the battery. So, I I used the existing 4-gauge leads that previously were going into the Norcold and used them to wire the fans. Then I ran a new 10-gauge wire positive wire from the cut-off switch to the to the Norcold and ran a 10-gauge ground directly back to the battery. 

I wrapped the 10 gauge positive and ground wires in 3/8” Protective Wire Wrap and ran it through the frame

I used the access holes already in place

Then I ran them up the wall on the side of the fridge to the top where you connect to the power block.

Sorry I don't have a picture of the 10 gauge wires and the new configuration but this is what the power block looks like. #3 is ground and #4 is positive 

Let me just say that this will work great if you have sufficient power going to your fridge. I shouldn’t have any problems on the road, because I have 200-watt permanent solar installation and a 200 AH battery bank to draw from. We primarily are running up and down the West Coast or camping in the Southwest where sun is abundant. Also, we have a strong 13.4 going to the battery from the from the 7-pin wiring. However, if your battery drops below 12.5 volts because your system can’t keep up with the 12 amp draw on 12-volt, it will not be able to keep up the needed cooling.

alanerickson

We have a 2018 with a 180.3 three-way Norcold in it that struggles to stay cold when the ambient is above 90F.  It doesn't have any cooling fans it and so that is going to be the first thing I add.   Is it recommended that I increase the 12V wire capacity at the same time, or should I just wait and see how the fans work at first?   And in general does the 12V upgrade give good results for the effort, or are there other things that should be done first?   Thanks.

dsatwork

Fans with the Air Baffle will do most of the heavy lifting. The 12 volt wire does insure that you are actually getting the necessary voltage to run the fridge at peak performance. Be sure to get my detailed guide from the files on the Facebook group I think. On it show the testing I did on all on 12v with the mods in place.

Spectre9

Be warned, if you run a ground from fridge direct to battery you may create a “ground loop” and cause issues with power converters and batteries and solar and things measuring voltages correctly.  Floating grounds cause issues with voltage feedback and stress capacitors, Circuit humming and interference etc.  Run same-sized wires to same source (properly fused)  and/or move battery.

in this case if fused and direct to battery it would be a okay!  

Grumpy_G

The OP and Val Rigoli start from the premise that 12V provides the same cooling as AC power or gas. But that is not how the manufacturer designed it, 12V operation is only meant to hold the temperature during travel with the tow vehicle providing power. Straight from the Norcold 180.3 manual:

The DC operation is not intended for the initial start up and cooling of the refrigerator. Always use either the AC operation or LP gas operation to initially start up and cool the refrigerator. The refrigerator must be cooled and the temperature must be steady before you operate the refrigerator on DC.Keep in mind the following guidelines for DC operation of the refrigerator:

- Use DC operation of the refrigerator while the vehicle is in transit.

- Do not use DC operation until the refrigerator and its contents are completely cooled.

- Only use DC operation if the vehicle battery and battery charging system are in good operating condition.

This makes all the effort to reduce voltage drop somewhat of a moot point. A few degrees F difference after a day of driving is not going to spoil all the food in the fridge. Trust me, I used to work in a grocery store as a teenager

dsatwork

Grumpy_G said:

The OP and Val Rigoli start from the premise that 12V provides the same cooling as AC power or gas. But that is not how the manufacturer designed it, 12V operation is only meant to hold the temperature during travel with the tow vehicle providing power. Straight frm the Norcold 180.3 manual:

The DC operation is not intended for the initial start up and cooling of the refrigerator. Always use either the AC operation or LP gas operation to initially start up and cool the refrigerator. The refrigerator must be cooled and the temperature must be steady before you operate the refrigerator on DC.Keep in mind the following guidelines for DC operation of the refrigerator:

- Use DC operation of the refrigerator while the vehicle is in transit.

- Do not use DC operation until the refrigerator and its contents are completely cooled.

- Only use DC operation if the vehicle battery and battery charging system are in good operating condition.

This makes all the effort to reduce voltage drop somewhat of a moot point. A few degrees F difference after a day of driving is not going to spoil all the food in the fridge. Trust me, I used to work in a grocery store as a teenager

I'm the original poster and that was not my premise, these fridges the way they were originally installed could never keep up in weather above 90 degrees and would regularly ruin food. It was only after many hours of research and testing that I realized what was wrong and how to fix it.

Spectre9

Honestly i wish I could delete post on phone but it only makes edit available as I realize I was distracting from original post so maybe just ignore my comment- I had multiple threads open so think I had read and reacted to a different modification strategy 

MarkAl

Interesting concept to improve the 12V op of the device @dsatwork , 2 questions. I missed whether it was successful in improving the above 90 degree operation.  I have only limited use with a 3 way but from reading, due to the large 12V current requirement, it is not normally used. Your 12 capacity seems to allow this operation.  Does this mod potentially improve the more common 120V operation? I don't know if the 120V is reduced to 12V for operation.  To me it seems improving the cooling for all the refrigerator types is the best win.

ChanW

Just FYI, I think the only way to delete a post is to ask the mods to do it for you...

Spectre9 said:

Honestly i wish I could delete post on phone but it only makes edit available as I realize I was distracting from original post so maybe just ignore my comment- I had multiple threads open so think I had read and reacted to a different modification strategy 

dsatwork

MarkAl said:

Interesting concept to improve the 12V op of the device @dsatwork , 2 questions. I missed whether it was successful in improving the above 90 degree operation.  I have only limited use with a 3 way but from reading, due to the large 12V current requirement, it is not normally used. Your 12 capacity seems to allow this operation.  Does this mod potentially improve the more common 120V operation? I don't know if the 120V is reduced to 12V for operation.  To me it seems improving the cooling for all the refrigerator types is the best win.

Yes although the primary focus was on the road on 12v operation, the overall performance was improved dramatically. Just adding the fans will make a marked improvement, the baffling forces the now pressurized air over the fins to bring the installation closer design specifications for an absorption refrigerator. 

dsatwork

MarkAl 

This is the third post in the series, 

Turbocharging the Norcold N 180.3 3-Way Fridge (double side vent models 2017 and newer)

is the title of the original post has links to all of the post in the series and contains the testing I did along the way.

https://tab-rv.vanillacommunity.com/discussion/5766/turbocharging-the-norcold-n-180-3-3-way-fridge-double-side-vent-models-2017-and-newer#latest

ChanW

I'm not worried about the post, I did solid work and it's easy to defend.