Norcold 3 way fridge drawing excessive current in "Battery" mode.

[JFK]

I'm unable to measure the exact current draw but it's enough to activate the on board "battery isolater" which in turn means the truck alternator is not charging the coach battery. I was able to trouble shoot the "DC heating element" with an ohm meter and got a reading of 1.1 ohms. I'm out of ideas as to what to look at next. The fridge is original to the (Lance) camper manufactured in 2007. Tried to contact Norcold "customer service", what a joke that is. Anyway would appreciate any input.
thanks, Jim

 

[AH64ID]

DC mode is a decent draw, are you sure it’s excessive?

From what I recall they draw about 15A on DC mode and the most I’ve ever seen my 7-pin provide to a trailer is ~10A, a slide in may be an amp higher since the run is potentially shorter. So while the fridge is running you are depleting the batteries even if the truck is charging the trailer.

 

[Topzide]

I would run a separate power hook up with Anderson Power connectors with at least 8ga wire or larger do to the length of run. The power drop is hurting the fridge and truck batteries. If you run separate power, try to use wire with the most strands possible! Think welding cable vs. battery cable. The more strands the more current and also flexible. This is one of the reasons that I have a clamp amp meter that goes 400A AC/DC. Sure help finding problems. Just throwing it out there. Good luck on finding the issue.

 

[AH64ID]

In addition to some increased wire size a DC-DC charger would also help.

You can run a 18A DC-DC charger on OEM wiring, but any larger needs bigger wiring.

 

[JFK]

Wiring from the engine compartment to the camper was accomplished by an "authorized" Lance dealer and was done in 2015 when I purchased the truck. All was fine. I've not made any additions to the electrical demand on the camper. Information decals on the inside of the fridge state amp draw & wattage p/ac & dc usage. In my case, dc is; 15amp & 144 watt. I could accept the small wire gauge suggestion if the problem arose after the dealer installed the harness, however this is a recent problem. Am I sure the current draw is excessive,,,,,,,,yes. It'll trip the camper's battery isolater, I can hear the audible "click" of the relay within seconds after selecting "Battery" on the fridges selector dial. The search goes on,,,,,,,,,,,,,,,,thanks all. Please keep the ideas flowing.

 

[AH64ID]

What I’m gathering is that in addition to your 7-pin connector there is another connection that was added by the dealership. What does this connection look like? Have you verified that fuse is not blown?

You need to measure the amp draw then, not much can be done without that aside from just throwing parts at it.

 

[petersonj]

Am I sure the current draw is excessive,,,,,,,,yes. It'll trip the camper's battery isolater

I really doubt there is excessive current draw. The heating element is very simple and dependable. A failure almost always results in higher resistance (drawing less current) or the circuit goes completely open (no current draw) Most RV manufacturers don't even offer the 12 volt refrigerator circuit anymore. When they were offered, they were so ineffective because of the high current consumption and long wiring runs with undersized wiring. Plus the charging source (the truck's alternator) is a considerable distance away - again, with long undersized wiring.

By applying ohms law with your reported resistance values, the heating element is not even drawing 15 amps. If you take the manufacturer's specs of the refrigerator (15 amps, 144 watts) that equates to 9.6 volts at the refrigerator positive and negative connections to get 15 amperes of current to flow.

I would suspect a low voltage condition is happening when the DC voltage supply to the refrigerator is turned on. I would also suspect the low voltage condition is caused by a poor connection or a low state of charge in the RV battery / batteries. I don't know how your camper battery isolator is set up, but I could certainly understand that it could trip if proper battery voltage wasn't present for whatever reason.

Over the years, I have had two campers in which I utilized 12 volt DC to operate the camper's refrigerator. In both cases I wired independent circuits with heavy gauge wiring from the truck's battery through a relay to the RV's battery - pretty much as @Topzide has suggested.

- John

 

[slowmover]

DC mode is a decent draw, are you sure it’s excessive?

From what I recall they draw about 15A on DC mode and the most I’ve ever seen my 7-pin provide to a trailer is ~10A, a slide in may be an amp higher since the run is potentially shorter. So while the fridge is running you are depleting the batteries even if the truck is charging the trailer.

Some can be even higher in draw. 12V is sorta “enough” to go short road distance. 7A “normal”, to 17A occasionally.

For 20’ at 20A (10% voltage drop) one can get away with 14-AWG. My preference would still be 10-AWG as it’s not difficult (size) to deal with. And at 50’ it’s still viable (alternator to reefer). 8-AWG stem to stern covers demand spike adequately (given proper install, connectors & terminations).

Expense for marine grade wiring package adds up quickly. The more critical volt drop requirements for radio have had me build $100-$200 harnesses for lengthy big truck needs in 6-AWG and 4-AWG.
Routing properly adds distance.

IMO, one shouldn’t regard expense as important over design/construction quality. Past water it’s electrical fires which destroy RVs. Measure, measure, measure.

Propane is what’s normally used for a full day on the road. 12V gets you from the turnouts at each end of tunnels where propane use is banned is a way of thinking about it. More about time than distance.

I see this as a full-timers dilemma, not Joe Vacationer. Travel planning is fresh refrigerator stock at each waypoint. Where day-trips around a region are the thing.

— Just as RVs consume a great deal more energy per square foot to be heated or cooled versus a house, so too is consumption via disposal of reefer basics. (Plan meals differently). One may well empty the camper and stay in motels on the return trip: there are many ways to travel.

Think dual use otherwise: A YETI cooler can preserve expensive items pretty easily for a road trip. I have a chest-style 12V/120V NORCOLD in addition to the built-in 3-way which flips from reefer to freezer with a switch. Adds freezer space in my normal RV use of it. Can ride in tow vehicle to run off cigar lighter.

Now you know why Propane is the literal definition of camper RV. Self-contained.

Electricity is third tier importance as water is the system (second tier) around which the camper is designed. Electrical is pretty much convenience, not necessity.

RV Camping is to chase shirt-sleeve weather. To enjoy being outdoors without the difficulties of setting up wall tents, dig latrines, etc., every few days.

Driving somewhere else just to watch TV is the sad state of todays “vacationer”.

I’ve seen $15k solar electrical added to already expensive trailers and seriously doubt it was worthwhile as propane could have met the need far more easily & efficiently.

DIY electrical, OTOH, to further an existing capacity so as to fully utilize it meets my criteria to make it a worthy project to plan. (Lagniappe). Adaptability-to-circumstance is an ideal.

Good luck.

.

 

[JFK]

WOW!! Thanks everyone. I may just abandon the option of the fridge since it functions perfectly on AC & propane. We also have a travel trailer with a 2 way fridge and it works just fine while on the road (in the propane mode). The Lances' fridge has a mind of its' own when it comes to using the propane function while driving. More often than not the flame blows out. We always pre-cool the fridge the day before leaving and try to keep the driving time to 5-6 hours which usually keeps everything cold enough to prevent spoilage. By then we're setting up camp and have either AC from a terminal or if boon docking use the propane function. As a side note I mistakenly said the fridge decal said 15 amp & 144 watts, it's 12 amps & 144 watts. And no fuses were blown. So I'm not going to 'throw $$$$" at the problem at this time since I can get by on AC & propane. thanks again, Jim

 

[slowmover]

Windscreen for propane flame is an RV topic older than time itself.

 

[Road Dog]

On the road my fridge is OFF. Driving time is typically 5-6 hours and the ice is still ice in the freezer. The fridge has an electronic igniter so it could deal with a blown out flame but I'd rather have the propane off at the bottle in case of an accident.

I have a Northern Lite slide in camper.

 

[crispyboy]

Just use the propane option while traveling down the road. As slowmover stated make sure there is a proper windscreen around the burner, the burner itself is in good shape and you have the proper pressure within the propane system. Our trailer only has a 2 way refrigerator. Ours actually works much better on propane vs 120v electric.
I understand that many of the new RV's only come with 12V compressor refrigerators. They are supposed to work much better than a gas absorption type but now you have to invest many $$ in a solar system to keep it running.

 

[SnoKing]

WOW!! Thanks everyone. I may just abandon the option of the fridge since it functions perfectly on AC & propane. We also have a travel trailer with a 2 way fridge and it works just fine while on the road (in the propane mode). The Lances' fridge has a mind of its' own when it comes to using the propane function while driving. More often than not the flame blows out. We always pre-cool the fridge the day before leaving and try to keep the driving time to 5-6 hours which usually keeps everything cold enough to prevent spoilage. By then we're setting up camp and have either AC from a terminal or if boon docking use the propane function. As a side note I mistakenly said the fridge decal said 15 amp & 144 watts, it's 12 amps & 144 watts. And no fuses were blown. So I'm not going to 'throw $$$$" at the problem at this time since I can get by on AC & propane. thanks again, Jim

Good plan, as they draw about 18 amps DC.

 

[Tuesdak]

They offered a separate high amp connection for the 3 way fridge when I was looking at slide in campers in 2016. Low voltage extended high current likely caused a bad connection somewhere. The 12VDC heater is essentially just a Glow Plug ... as you noted by 1.1 ohms. Look for crispy corroded wire connections or with an IR temp gun for a hot connection. I would start by checking the grounds on both the camper and pickup for the high current connection. An open ground may be trying to send excessive current through the normal smaller ground. Bad positive connection including failed fuses may be doing the same to the small positive connector.

Do not assume the RV batteries are good or charged: heed the advice and test them. It may be a secondary problem.

Even without using the fridge in 12VDC mode the high amp connector can charge the camper batteries faster when going down the road. So it's worth fixing regardless.

I also use an aftermarket protection device, Fridge Defend by ARP, as off level boiler operation like some of the extreme grades we have around AZ can overheat the boiler. Do it enough times and the boiler leaks sometimes as a fireball. The Fridge Defend shuts the fridge down on just high temp, before overheat, and restarts it after it's cooled down to reasonable.

Dry ice is a great way to speed up the cool down and keep the RV fridge cold.

 

[slowmover]

That ARP device looks GTG. Thx

And, use of dry ice has a learning curve.

 

[p-Bar]

Slomover is correct, just create a windscreen. My dad had to do this on our 68 camper van.

 

[2Farr]

I did the inverter that powered just the fridge on our fifth wheel. It was a 350W. I could run it most of the day on the road but if the out side air temp got around 80 it was too much for this set up. I installed a 6500W onan gen. I can run this on the road and not worry about the fridge. It is also nice we can just pull off the road and flip on the AC or just about any thing.[/ATTACH]