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-   -   Norcold N400.3 12V operation issues? (https://www.irv2.com/forums/f54/norcold-n400-3-12v-operation-issues-555574.html)

nhinze 09-26-2021 04:23 PM

Norcold N400.3 12V operation issues?
 
I recently acquired my first used horse trailer with living quarters. It came with a Norcold N400.3 fridge. I'm having trouble keeping it cold when traveling and using the 12V operating mode. Here are the steps I take before a trip:
- Cooldown the fridge 12+ hours overnight using shore power. The fridge is nice and cold in the morning.
- Only place cold items in the fridge before leaving.
- Turn to battery/12V mode on departure.
- I have two brand new 77Ah 12V batteries powering the trailer.

The fridge seems to get warm fairly quickly even though it is draining my batteries. What should I expect from the 12V operation of such a fridge?

It pulls 14.2A at 12VDC. Unless my math is wrong, I would expect it to be able to run for (77Ah * 2) / 14.2 = 10 hrs. Is this an unreasonable expectation? Even in fairly "cool" weather".

THenne1713 09-26-2021 05:18 PM

First, Expect 50% of that? Then, should be 7-pin harness/ plug, with IGN controlled B+ supplying power while traveling?

Old-Biscuit 09-26-2021 10:36 PM

Norcold N400.3 uses either a 150W or 195W DC Element (production year dependent)

Does pull 10a-17A when energized
*resitance test S/B 0.8 to 1.2 ohms

BUT as posted above there S/B a 12VDC Power Line from tow vehicle to trailer (7 pin)
If 6 pin or 4 pin...no power line/no charging-maintaining trailer batteries with high amp draw

What is battery voltage when you start trip and when you arrive at destination???

nhinze 09-27-2021 04:30 AM

I have a 7pin connector. I need to check that I get power on the blue pin.

When I start the trip it is 13.2V. At the destination, it was 12.0V once and 11.8V another.

Sbrownstein 09-27-2021 05:50 AM

Simple, what is the battery voltage when you start the truck and are connected? S/B greater than 13 volts if there is a working charge line.

Persistent 09-27-2021 09:04 AM

Quote:

Originally Posted by nhinze (Post 5929481)
I have a 7pin connector. I need to check that I get power on the blue pin.

When I start the trip it is 13.2V. At the destination, it was 12.0V once and 11.8V another.

Static voltage values indicate approximately 50% or more discharge. Charge line from tow vehicle is not replacing current drawn.

Increase in temperature inside refer may be due to air flow in cooling system while underway.

nhinze 09-27-2021 03:35 PM

I have two 7 pin plugs on my truck. The one that came with the truck reads 13+V when the engine is on. The after market one I had installed for my 5th wheel is not reading anything for the charge line. All other work (Lights, turn signals, brakes, etc..). Probably a loose connection somewhere, because I doubt there are separate fuses for the two plugs.

Sbrownstein 09-27-2021 03:47 PM

Quote:

Originally Posted by nhinze (Post 5930189)
I have two 7 pin plugs on my truck. The one that came with the truck reads 13+V when the engine is on. The after market one I had installed for my 5th wheel is not reading anything for the charge line. All other work (Lights, turn signals, brakes, etc..). Probably a loose connection somewhere, because I doubt there are separate fuses for the two plugs.

Or...when they wired it they didn't wire the charge line. Take the cover off the receptacle and see if the pin is wired.

nhinze 10-01-2021 09:16 AM

Center pin is not wired and no loose wire to connect to it :-(.

Sbrownstein 10-01-2021 09:21 AM

1 Attachment(s)
Quote:

Originally Posted by nhinze (Post 5934797)
Center pin is not wired and no loose wire to connect to it :-(.

Hope you mean the center pin of the 6-way, the center pin of the 7-way is for backup lights.

nhinze 10-01-2021 10:27 AM

I just realized that I tested the wrong set of pins on my 7 way plug. So, the ground (-) and opposite (Battery +) pins read 14+V with the engine on with both the built in and after market plug.

However, the voltage reading in the trailer quickly drops down to 12.5V when I put the fridge on battery mode.

Sbrownstein 10-01-2021 10:58 AM

Quote:

Originally Posted by nhinze (Post 5934875)
I just realized that I tested the wrong set of pins on my 7 way plug. So, the ground (-) and opposite (Battery +) pins read 14+V with the engine on with both the built in and after market plug.

However, the voltage reading in the trailer quickly drops down to 12.5V when I put the fridge on battery mode.

...and if you turn off the TV? What happens then? The charge lines are notoriously small so a significant voltage drop under reefer load might be expected. Be interesting to know what the charge current is with both the TV and reefer running, but without a DC non contact probe it might be difficult to measure.

nhinze 10-03-2021 05:47 PM

This trailer came with a small solar panel on the roof. I'm guessing less than a 100W probably. The trailer was built in 2006. The voltages I'm reading are from the "Solar Regulator" screen. It also has a "Battery Charge Indicator".

When plugged into shore power and the fridge on it says it is charging the battery at 14+ V. Removing shore power and connecting to the vehicle with the engine on, the charging voltage drops to 12.5V.

I don't have a TV in there. Essentially only the fridge, lights, and radio are 12V.

Is this whole setup ignoring the vehicle charge line and defaulting to the solar panel? That tiny panel cannot keep up with the demands on the fridge in 12V mode.

Sbrownstein 10-03-2021 05:50 PM

Quote:

Originally Posted by nhinze (Post 5937263)
This trailer came with a small solar panel on the roof. I'm guessing less than a 100W probably. The trailer was built in 2006. The voltages I'm reading are from the "Solar Regulator" screen. It also has a "Battery Charge Indicator".

When plugged into shore power and the fridge on it says it is charging the battery at 14+ V. Removing shore power and connecting to the vehicle with the engine on, the charging voltage drops to 12.5V.

I don't have a TV in there. Essentially only the fridge, lights, and radio are 12V.

Is this whole setup ignoring the vehicle charge line and defaulting to the solar panel? That tiny panel cannot keep up with the demands on the fridge in 12V mode.

Turn off the fridge with the TV connected. Voltage needs to be over 13 volts with no load from the trailer. Otherwise you are not really connected.


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