Refrigerator modifications

^^^excellent comment^^^

NRALIFR wrote:

Those of you who advocate turning the fridge off should really think about what could happen if the wrong person blindly followed your advice. We don't all have the same fridge, we're not all from the same parts of the country, our immune systems aren't all alike, and we don't all load our fridge up the same way.
Food safety is serious business, and keeping food at safe temperatures is key to keeping it safe. Every person who works in the food industry knows that you either keep it hot, keep it cold, or you don't keep it. The danger zone in the reefer section BEGINS at 45, and the higher it goes from there, the faster food spoilage occurs. That slightly tainted piece of meat or carton of milk that tastes a little funny might be tolerated by a healthy adult, but it could actually kill a child or any person with a weakened immune system.
:):)

GREAT advise! We all need to keep our food safe while camping.

To the OP, you can do it either way, and both work. We run our fridge on propane when on the road.

Yes, I run my fridge on AC with an inverter while on the road. But, it's not because of any fear of propane leaks fire, or explosion. I simply got tired of trying to fix whatever was causing the flame to get blown out on the road. I had to significantly increase the size of the 12v charge wires to the camper battery so the alternator could keep up with the ~345 watt draw from the inverter though. Six gauge wires from the alternator to the 7-pin plug in the bed. You might have to go even bigger on a TT due to the length involved.

Those of you who advocate turning the fridge off should really think about what could happen if the wrong person blindly followed your advice. We don't all have the same fridge, we're not all from the same parts of the country, our immune systems aren't all alike, and we don't all load our fridge up the same way. I would recommend anyone considering this put a wireless thermometer in your fridge to monitor how warm it gets while it's turned off. Food safety is serious business, and keeping food at safe temperatures is key to keeping it safe. Every person who works in the food industry knows that you either keep it hot, keep it cold, or you don't keep it. The danger zone in the reefer section BEGINS at 45, and the higher it goes from there, the faster food spoilage occurs. That slightly tainted piece of meat or carton of milk that tastes a little funny might be tolerated by a healthy adult, but it could actually kill a child or any person with a weakened immune system.

Because I monitor the temperature in my fridge while on the road, I can tell you for a fact that the 12v mode on mine is useless. It won't even keep up with a moderately warm day here in the south (85 deg). It's a waste of amp-hours from the camper battery to try to keep it cold on 12v, so I unplugged the 12v element years ago. I can also tell you for a fact that the fridge warms up to above 50 degrees very quickly on one of the all-to-typical 90+ degree days we have around here. So as far as I'm concerned, it's either run it on LP (which isn't reliable on the road), run it on AC mode through the inverter (which works very well), or if both of those failed go buy a chunk of dry ice. Turning it off means food I would be hesitant to eat, and I damn sure wouldn't serve it to a guest.

:):)

I only run my fridge on 115AC via the inverter/alternator when driving. If I am underway, my propane bottles' valves are always closed!

I acknowledge the chance of a "problem' is low and that there is indeed an incremental dollar cost for the additional power needed to spin my (180A) alternator, but the benefits far outweigh the costs. Here's my perspective;
- Much of my travel includes extended boondocking in remote areas where propane may not be readily available. Diesel fuel typically is widely available, and I carry a spare fuel can just in case.
- I don't need to turn off the fridge at gas stations, on ferries, or tunnels with propane restrictions.
- I frequently travel on unimproved/dirt roads and my entire rig is subject to a lot of vibration. If a propane line were to become fatigued and leak, it is most likely to happen while underway. Since my LPG bottle is off that risk is eliminated. **
- I am much more likely to notice a propane leak while parked/camped (odor, sound, LP detector) than while driving.
- In the event of an accident my LP is off so again the risk of a leak/fire is greatly reduced.
- The risk of wind blowing-out the propane flame/pilot is eliminated
- The fuel cost (diesel or propane) to run the fridge, regardless of driving or camping, is so small that it don't even include it in my travel budget.
- When I get to my destination I have the same amount of propane in the bottles as I did when I set-out.
- I have an ammeter mounted in my dash that displays power going to my camper and I can tell at a glance if the fridge is cycled on or off.

For those who don't have appropriate inverter set-up, I will add that (once cold) my fridge maintains its temperature equally well in both DC and AC modes.

I do not necessarily think that others need to subscribe to my somewhat conservative "better safe than sorry" point of view, but I do know running my fridge on AC power has served me well for many many thousands of miles so far.

Cheers,
-Mark

** By the way, if you are wondering if/how a propane leak can occur, just take a look at this thread: Wolf Creek 850 possible propane leak.

just eat all of the food and drink all of the beer before you leave and you don't have to run it either way. lol

I tried that when I had a TT. After about 4 hours the TT battery dropped too low and the inverter shut off. The charge connection between the TV and the TT was not adequate to keep the battery charged. I never did try to improve the connection.

I was using a 300w inverter. That could have been drawing close to 30A. Never did measure the current.

I actually did the calculations a few years ago and at the time, the cost of extra gasoline to run the alternator was about 50% greater than the cost of the lp.

12v is not free
The 245w heating element will draw have an inverter draw of over 20amps
That power has to come from the drive engine turning the alternator
The fridge uses very little propane
The cost of the propane used will be less than the cost of the gas used to create the power coming from the alternator

As far as safety, I used a propane fridge on l.p. for 16 years straight, never on electric , always propane moving or parked, only turned off during lp refill
This RV has a residential 120v compressor fridge
But that is another topic

Bumpyroad wrote:

naturist wrote:

Bumpyroad wrote:
lets see, using 12 volts is free, burning propane is not.
bumpy

Mmmmm, I don't think so, @bumpy. That 12 volts comes from the battery, but before that it comes from either the vehicle alternator or your generator, which you pay for the fuel. An RV 'fridge is going to use 600 watts more or less, and that is way too much to expect the charge you put on the house battery to cover for a whole day traveling. So don't count on "free" electricity from the campground to cover this one.

So it's gonna cost you to keep the 'fridge cold, whether you use propane or 12 volts. However, it isn't going to cost you much either way.

is my alternator spinning harder if I am using extra juice?
bumpy

Actually the answer is yes, your alternator is working harder which translates to your engine working harder (granted a small amount, 600W additional load is just under 1 HP but would be adding about 47A load to the alternator). You WILL use a bit more fuel.

Each "conversion" of energy involves losses. Engine converts gas into rotational energy, alternator turns rotational energy inverter turns 12V DC into 120V AC. Each conversion creates a form of heat which represents loss, typically you really want to avoid multiple conversions as much as possible.

A absorption fridge running directly from a very SMALL flame from propane uses a very small amount of propane. Just not sure if it is worth it to add more load to the vehicle alternator (replacement alternators are not cheap even when rebuilt)..