Refrigerator Woes...Finally Caught Up With Me!

[Larryjb]

Originally Posted by tentcamper

Im convinced that running the fridge on LP while traveling causes an in-efficient burn and soots up everything and leads to the rust. I think it is closing the shell and the fan running that changes the fuel to air mixture that leads to the in-efficiency and more soot and acids in the burn.

Our first TM, we traveled on LP and twice I had the issue within 18 months or each other. I switch to 12v and rewired so the fridge ran on the auto battery when traveling and only ran LP for camping without electric. I did not have a dirty burner after that.

If you decide to try using the auto battery for the fridge, many people have found they had to upgrade the TV wiring. Then, if you stop for awhile (like taking a ferry, lunch, sightseeing etc), you will want to remember to disconnect the trailer bargman or you will drain your TV battery!

We keep ice packs in the freezer at night, then put them in the fridge during the day when travelling. This has always kept our fridge cold, even in the California heat.

By the way, the only issue I've had with our fridge so far was lighting it. Different models of fridges were used through the years. In ours, I found that the piezoelectric igniter adjustment is extremely sensitive. I spent a 1/2 hour trying to light the thing once and thought it was the burner. It still wouldn't light. Then I found that I had to adjust the igniter and that solved the problem.

[FlyboyTR]

Originally Posted by Larryjb

If you decide to try using the auto battery for the fridge, many people have found they had to upgrade the TV wiring. Then, if you stop for awhile (like taking a ferry, lunch, sightseeing etc), you will want to remember to disconnect the trailer bargman or you will drain your TV battery!
.

TentCamper,
You may very well be right about towing with fridge on LP shortening the burner life. My view is that the little flame is hid behind two partially sealed outside walls, recessed in and behind a louver and inside a protected steel cover...But...I guess anything is possible. In 285k miles of RVing, I have never had a burner failure. I will have another 8k mile trip coming up in the fall...so I may have to do a before and after inspection.

Larry,
You have given me food for though regarding the 12 volt side of things. For some reason, I think my Lexus power lead for the trailer is only hot when the engine is running. I will double check that. Also, I have no idea of the size wire and capacity of the factory installed power lead for the trailer. I doubt it is 10 gauge or larger. Honestly I have never even checked to see if I have a voltage drop on the trailer battery when connected to the Lexus and fridge running on the 12 volt heater. I may add that to my to-do list.

[Bill]

Travis -

My experience with my old 2002 TM and 2002 Ford Explorer. The refrigerator is much closer to the TM battery than it is to the tow vehicle battery. That means that the current from the two batteries is unequal because of the unequal voltage drop in the wire runs. The refrig drew most of its current from the TM battery, with the result that when we arrived at a campground, the TM battery was dead. Annoying! I did a partial fix by installing an entire new run of #10, including a separate connector, from the Explorer's alternator directly to the TM battery (the Explorer's OEM wiring had quite a bit of #12, and several connectors, in the line). It helped quite a bit, but not enough. I ended up with Larry's approach. Just get the refrig real cold in the campground, make ice, then close it and turn it off until the next campground. With power off, the refrig is still a really good cooler, and after 6 or 8 hours on the road, we still had cold food.

One of our members did a much more elaborate fix by converting the nominal 12 VDC in the engine compartment to 24VDC, running a separate 24 volt wire back to the TM, and then converting it back down to battery charge voltage in the TM. That eliminated the voltage drop of course. He reported that it worked like a charm.

Bill

[FlyboyTR]

Originally Posted by Bill

Travis -

My experience with my old 2002 TM and 2002 Ford Explorer. The refrigerator is much closer to the TM battery than it is to the tow vehicle battery. That means that the current from the two batteries is unequal because of the unequal voltage drop in the wire runs. The refrig drew most of its current from the TM battery, with the result that when we arrived at a campground, the TM battery was dead. Annoying! I did a partial fix by installing an entire new run of #10, including a separate connector at the hitch from the Explorer's alternator directly to the TM battery. (The Explorer's OEM wiring had quite a bit of #12, and several connectors, in the line). It helped quite a bit, but not enough. I ended up with Larry's approach. Just get the refrig real cold in the campground, make ice, then turn it off and don't open it, until the next campground. With power off, the refrig is still a really good cooler, and after 6 or 8 hours on the road, we still had cold food.

One of our members did a much more elaborate fix by converting the nominal 12 VDC in the engine compartment to 24VDC, running a separate 24 volt wire back to the TM, and then converting it back down to battery charge voltage in the TM. That eliminated the voltage drop of course. He reported that it worked like a charm.

Bill

Bill,
Good info. Lots to think about. I have (way in the past) thought about using an inverter, mounted in the engine compartment (so short heavy leads from the battery to the inverter). Then taking the power from the inverter at 110vac and run it to the fridge (wired directly to the fridge). This would require turning the breaker off that controls the fridge to prevent backfeeding to the camper. Still a crapshoot...but something to consider.

We have a 30 quart 12/12/110 volt portable fridge/freezer that is compressor driven. When running on 12vdc it averages around 3.5 amps, does a great job and we have used it on a lot of our overlanding/camping trips. I wish there was a cost effective option for a system like this for the RV world. I paid $280 for the Alpicool. They do have larger units but they are all top access...not front access.

Thanks again!

[Shane826]

Originally Posted by FlyboyTR

Actually.....my post was about finding a problem with my refrigerator and using the resources of this group to find the cure. Thankfully everything worked.

Unfortunately....it was turned into a shame on you for pulling your camper with your LP refrigerator on. REALLY.... ???

That’s how conversations happen. I know, it’s scary. Nobody is shaming you. But somebody may have experience as to why on a folding camper like a TM, running the fridge on propane while towing might not be the greatest idea. I know, you “always have, always will”.

[tentcamper]

I run my fridge off the TV battery. I have a battery switch. When I turn off the the TM battery the only source for fridge power is through 7-pin battery 12V pin from the TV. So when I travel the battery switch is off.

I made one modification. The stock wiring, When the battery switch is off there is no power to the breakaway brake. So I wired the breakaway brake directly to the TM battery. Simple with my TM with the battery on the tongue.

My TV battery is always live at 7-pin I have never had an issue with running my battery down when stopping for lunch. But I do disconnect for long stays.

[Bill]

Sounds like a great solution. It seems simple in hindsight, but I never thought of doing it.

Bill

[rickst29]

Originally Posted by Bill

Travis -

My experience with my old 2002 TM and 2002 Ford Explorer. The refrigerator is much closer to the TM battery than it is to the tow vehicle battery. That means that the current from the two batteries is unequal because of the unequal voltage drop in the wire runs. The refrig drew most of its current from the TM battery, with the result that when we arrived at a campground, the TM battery was dead. Annoying! I did a partial fix by installing an entire new run of #10, including a separate connector, from the Explorer's alternator directly to the TM battery (the Explorer's OEM wiring had quite a bit of #12, and several connectors, in the line). It helped quite a bit, but not enough....

One of our members did a much more elaborate fix by converting the nominal 12 VDC in the engine compartment to 24VDC, running a separate 24 volt wire back to the TM, and then converting it back down to battery charge voltage in the TM. That eliminated the voltage drop of course. He reported that it worked like a charm.
Bill

Just a review for everyone else, you both know all of this.

While towing, at the TM's 12V distribution board (full of fuses), two sources of "+12V" power compete with each other (while power is being pulled away by the fridge at roughly 12A - it's a one-ohm resistance heater). "+12V" Battery Voltage will always be in balance on the board. At extremely low current, the Tow Vehicle would be preferred (with operating Voltage at about 13.5V). But, through really long wires and multiple connectors, with some of the wires quite small, the TV path suffers large and increasing 'Voltage Drop' as current begins to increase. The 10-AWG copper wire to the TM house battery can support much higher current, with lower Voltage Drop.

When the TM house battery is offering power of 100-110 Watts with a Voltage of 12.0 - 12.6V at the board, and at high current, some current WILL come from the higher-voltage TV path until 'Voltage Drop' on the TV path has increased to equal that Voltage along the battery path. But resistance increases so quickly on the thin wires, current is very small (under typical conditions). The TV is probably only 'contributing' 10-20 watts when the TM battery is above 70% charged.

But the TM battery gets drawn down pretty quickly. As it's supply voltage begins to fall (to perhaps 11.8 - 12.2) it's endpoint voltage (while supplying considerable current WITH some Voltage Drop) becomes less attractive at the board, and a larger proportion of current is pulled fro the TV. In a typical scenario, with decent but not 'exceptionally good' TV wiring, the TM batteries will be pulled down to about 50-60% SOC before the Tow-Vehicle path becomes dominant. The TM batteries should not be 'killed', but they will be unable to provide much power in camp. (However: with a badly compromised or broken TV 'trailer battery charge' wire path, TM batteries COULD be killed, because the Norcold fridge (running 12V mode) will never disconnect from 12V power due to low voltage.)
- - -
Running 'high voltage with lower current' from the TV requires that a Solar Controller modify the voltage back down to a safe level (for the TM batteries to absorb). High Voltage does not go to fridge directly, or into the 12V distribution circuit board - it goes through the Solar Charge Controller, to the battery terminals, and from there it goes back to the 12V Distribution Board. (It also offers to charge the batteries, since much more more 140 watts is being offered. The batteries may or may not be in a position to accept a charging voltage above "Float".)

I currently use a boost to 36V, the other user of this modification (klpauba) is using 24V. When this circuit is active (disconnecting the genuine TM Solar Panels and connecting the Tow Vehicle 'trailer battery charge' instead, the TV appears as a single large solar panel.

[FlyboyTR]

Lots of great information about improving the 12 volt side of running the fridge while towing. For us, it is a Long way from the TV Alternator to the camper battery at the rear of the trailer.

I am going to start giving this some consideration VS towing with the LP running on the fridge. Thanks again. Good stuff!

FlyboyTR

[ThePair]

End of last season I installed a DC to DC boost charger to my battery to take any volts > 10 and boost to the proper (14 ish) for the battery to charge. It's a 3 or 4 stage charger so it adjusts the battery charge as needed properly, bypassing the built in charger when powered up through the 7-way. I haven't tested it yet, hopefully that will be tonite or tomorrow.

If it works, I should arrive at the campsite with a cold fridge (on DC) and a full battery. I'll let you know how it works.