Running on DC redux.
 

Just got home from week long trip along Lake Superiors south shore @ Pictured Rocks Nat Lakeshore. 5 nights dry camping. Anyway it's about 350 miles home and drove it straight through yesterday. I usually don't but I left the fridge on dc on the road home to see how it would do. Normally a run like that would charge everything up but when I got home the multi meter was showing about 12.4 which means the truck charging system wasn't keeping up with the fridge drain. Good to know. I may go with Jacks solution and run an 8 gauge wire directly back from my truck battery to the trailer batteries ( two group 27s).

Rick

Welcome back- sounds like a great time, Rick!

I'd be curious to hear more electrical detail about your 5 night dry camping experience as that's the type of camping I prefer. I'm assuming you have dual batteries. Do you have a means to charge them while camping or are you just ultra-conservative?

Thanks,

Hey

Generally I'm pretty conservative( and the wife will tell you. "anal") on electrical useage. I use electric lanterns inside for most stuff inside and carry a "mr Buddy" propane heater for taking the chill off if I dont want to run the furnace. REfrig stays on propane, and works just great that way. Yes- I've got dual batteries (group 27) which gives me about 200 amps hours. I ave also switched most the interior lights to LEDs because my wife doesn't always like to knit or read by flashlight. :) I do have a small generator which I have never used (but plan to) as long as I am in a place that will let me use it to re-charge batteries when need be. I'm not generally running a television or stuff like that. In other words- I tend to approach it like I did tent camping with lots of battery operated stuff or 12 volt chargers I can re-charge with off the truck system. I also carry a small solar panel which works well if I am parked where there is access to the sun most the day- and move it around as need be. That is also something I am likely to add to ( bigger). There are a couple of folks on the board who pretty much dry camp ( or "boondocking" ) quite a bit- so search those posts. Jack ( and Janet) is one who does a lot of camping on BLM lands and is pretty handy at this stuff and I've borrowed more than one of his ideas. If you plan appropriately it is pretty do-able. Like I have said before- plan on living "out of the trailer" and not " in the trailer" and it works pretty well.

Rick

My wife and I are getting ready to go on a trip (our first in the Hi-Lo!) in a few days and have been debating on whether to try running the fridge on DC. Our destination is about 4 hours away but I may need to stop for 2-3 hours on the way so I'm concerned about the batteries draining down during the stop. We will have electrical hook-ups at the campsite though. My battery setup is the same as yours. Maybe we'll just use a cooler until we get to the campground.

Thanks for the info, Rick. I'm going to start a list of all these great ideas our forum members have on boondocking. Keep 'em coming! :)

Greg, hope you have a super trip. If you stop, you should not run the refrigerator with the top down for more than one hour (due to the poor ventilation). Personally, if I were stopped 2-3 hours, I'd raise the top and switch the refrigerator to propane. It is MOST efficient using propane.

At the campsite, since electrical power is available, I'd run the thing on AC.

In any case, you should have the refrigerator in the cool down mode at least a day before you depart. This kind of device does NOT cool down very fast, so you want it cold before you put food in it. And, if you're stopped for a long time, you DO want it cooling.

We always use a cooler with an ice block in addition to the fridge, because Janet likes a lot of fresh vegetables and other things that need to be kept cool. And, we like to minimize our "shopping". We can usually do a two week trip with what we start out with.

Hope you don't think I'm giving you the "idiot treatment". It's taken us a few trips to work out the best way to do things.

- Jack

Greg

If I was being cautious and I was running on dc while on the road I would UNPLUG my trailer from truck while doing an hour lay-over. JUST remember to re-plug when you take off again. Like Jack said, cool it down ahead of time. Over night on ac or propane usually does it for me. I prefer to run with stuff in a cooler on longer drive and transfer when I get there and then use cooler for beverages so I'm just wasting ice chest air every time I grab a beer or water or whatever
I've even run with some dry ice in fridge while on the road rather than dc if I want to keep it cool and ready when I get there or travel with perishables in fridge. At any rate, if you are going to have hook ups when you get there you should be ok as whatever electrical deficit you might get on the road will get recharged once you plug in. I usually go overboard worrying about this stuff so I am sure you will be ok. Remember to have fun. :)

Rick

Unless you are in a very hot location you can turn the fridge off for the 2-3 stop. Assuming everything is cold or frozen inside things stay cold quite a while. We have done it lots of times. We have also run the top up on long stops and switched to LP, just find a fairly level location.

Thanks for everyone's input! I've had the fridge chilling since last night (empty) on electric. Even on the warmest setting, the fridge is around 25 degrees and the freezer is a little below 0. Ambient outside temp is 69 degrees.

We decided to turn it off on departure in the morning. We'll run with it empty, except for some ice in the fridge portion, as an experiment to see how cold it stays. We'll travel with the cold food in a cooler in the tow vehicle and transfer when we get to the cg.

I hope that sucker doesn't freeze all the food when we stock it!

Greg, the refrigerator will stay cooler if turned off if it is stocked with cold food. Note that Rich's advice included having a cold, filled refrigerator.

- Jack

Noted, Jack. That's where the experiment part comes in. :)

The first part of our journey (about 4 hours driving time with a possible 2-3 hour stop on the way) we'll have it empty (except for a jug of ice). I'm sure it will warm up quite a bit but I want to see how good the fridge seals as an "icebox." We'll have electric at the campground so will plug in upon arrival.

The next leg of the journey is about another 4 hours with no anticipated stops other than a few groceries. We'll start out with a cold fridge (turned off) with some food in it to see how it compares. We'll have electric at the second cg as well.

In the future, I'll try running on DC to see how that works.

I forgot to mention that, also remember that the fridge will increase temperature during the time of loading it. Just remember to have all items cold before loading into the fridge. If warm items like beverages are going along put them in the night before.

Just returned from our trip and the fridge performed very well. It appears to seal correctly and keeps the food chilled for several hours with no power so it makes a good cooler. :D

One thing I noticed is that, even on the warmest setting, the fridge compartment stays very cold, almost to the point of freezing. Not sure how to fix that. What I tried doing was NOT running the external fridge fan, thinking that may help to keep it a little warmer inside. Thoughts?

Greg,

We have the opposite problem, our fridge normally runs too warm. We had to replace the external fan and also to add an internal fan, just to get the fridge cool enough.

Your posts are both interesting, Greg and Les.

My refrigerator seems to be more like the one Les has. A remote digital thermometer in it NEVER gets below about 43 degrees. But, ice forms quickly in the freezer section and nothing ever seems to spoil.

I used to worry about it, but I've stopped, since I'm not seeing any spoilage problems.

My guess is the thermostats are not particularly good.

- Jack

Right now I'm using non-digital thermometers but was thinking about getting a digital style with remote sensors but wasn't sure if the sensors would work due to signal loss if they are inside a fridge. It sounds like it's working for you though, Jack, so maybe I'll try it next camping season.

Yes Greg, a wireless indoor/outdoor thermometer seems to work just fine. I have the readout (receiver) mounted between two cabinets over the sink, which is about 4-5 feet from the refrigerator and the outdoor transmitter is in a plastic baggie (to keep it dry) mounted to the back inside wall of the refrigerator section.

The trick to mounting the transmitter is to find a place where it won't get in the way of food that is stored, but still is fairly "central" in the refrigerator section.

- Jack

If there is a sensor attached to the fins in the fridge try sliding it up or down to see if it makes any difference.

Thanks, Rich. I'll look for that.

- Jack

On second thought . . .
 

It turns out that the two mechanical thermometers that I used to test the fridge and freezer compartment in the trailer are bad. Not only do they not keep the correct temp, they also were not tracking with each other. I tested them by putting them inside my home fridge, along with a digital weather station remote sensor. The good news is I found out my home fridge and freezer was running too warm so adjusted the thermostats accordingly. The remote sensor did lose signal with base in the home fridge so that's a concern.

The bad news is I have no clue how the RV fridge and freezer compartment are performing. I'll probably wait until next camping season to test it.

The sensor should work ok in the trailer fridge, there is less metal to shield the signal. My sensor works fine in our fridge.

Rich, to respond properly to your suggestion, I was out winterizing my trailer this morning and checked the refrigerator. There IS a sensor in a white sleeve attached to the left most fin in the refrigerator. It was in the lowest position, so I've slid it to the uppermost position. Guess I'll have to wait until next camping season to see if it changes the temperature in the refrigerator section, but this is certainly an item to consider if your refrigerator temps are not what you want.

Thanks bunches!

- Jack

That's what that thing is! On mine, there is a sticker on the fridge wall that has a blue triangle pointing towards the sensor but I see no reference point on the sensor sleeve. Any idea what that's about?

If you have the manual for the fridge look to see if there is any reference to the sensor/thermistor. I have seen lots of talk about it on the RV.Net RV and Camping Forum ? RV, Trailer, Camper, Motorhome, Camping and Campground Information

On our recent one month trip we did not have any issues with the frig on d/c from Southern California to Moab, Utah (total of 4 days RV camping), however, about four hours after leaving Moab we arrived at a dry campground in South Mineral, Colorado and our batteries were dead. Stayed at South Mineral 2 nights with batteries charged and left for Mesa Verde, CO (refrig on d/c) and arrived again with dead batteries. Left Mesa Verde with charged batteries and dropped down into Aztec, New Mexico for about two hours and then drove (with refrig off) to Pagosa Springs, CO to an RV Park, no problems with batteries. Left Pagosa Springs with refrig on d/c and drove to Childress, Texas, arriving with dead batteries. Left the refrig off for the remainder of the trip while in transit, which remained cold but the freezer did cool down a bit on some of the stretches through western Texas. Back home, electrical was checked and the trailer batteries should have been receiving a charge while in transit.:(

Tow vehicle charge lines are notorious for having under-sized charge lines. For some reason the car companies use too small wire for the application. You say you checked and have power coming to the trailer which is good. Something that has happened is that your batteries have gone dead on several occasions, that's bad for them. That will essentially kill the life of the batteries, by now the damage has already been done. Put a good charge on them at home and let them sit idle overnight, then take them to a battery shop and have them tested. Two things you can do, run a heavier gauge wire from your TV or don't keep the fridge on all the time you are traveling. We rarely run the fridge while on the road for four hours or less, if everything is cold when you leave home it will stay cold for a number of hours.

If you have a good charge line and good batteries you should be able run all day with no problems. If you stop along the way shut off the fridge. If we stop for any length of time I park on a nearly level spot and raise the top and switch to gas.

To add to Rich's post, Garry, it really sounds to me like your battery charging fuse in the tow vehicle has blown. I found this can easily happen, especially if you raise the trailer top with the trailer electrically connected to the tow vehicle and the engine running. The draw through the charging circuit then is very high. I went through 3 fuses when my trailer was new before I learned this.

If you haven't done it, apply a voltmeter to the battery charging pin and ground pin at the 7-pin plug on your tow vehicle with the engine running. You SHOULD see something in the neighborhood of 14V if that circuit is active. If you see much lower voltage, your charging circuit is not up to par, possibly due to undersized wires or corroded/loose connections. If you see zero volts, the fuse is blown.

- Jack

Hi Jack,

Electrically challenged here . . . can a multimeter be used to perfom the check you mentioned?

Thanks for the input Jack and yes I had checked the fuse in the truck and all was well. My son checked the 7-pin plug and all was well with the plug. With that said, after returning from the trip, I did clean the 7-pin trailer plug with a very thin, small file, so a dirty plug could have been part of the problem. When I complete repairs to the water heater I plan on charging the batteries and then having them tested, though with a multi-meter I still get good readings.:confused:

Hi Greg - Yes, a multimeter would work fine. The "multi" part of the name means it combines AC and DC voltmeter and Ammeter functions, as well as Ohmmeter and continuity and sometimes other functions.

You would need to turn the selector on the meter to the DC volts position and possibly set the "range" value to an up to 20 volt reading. Many multimeters now though are "auto ranging", so you'd just need to set it to DC volts.

Hope I'm making sense - your meter should have a manual that will tell you how to set it up to read DC volts.

- Jack

Garry, I don't blame you for being confused. I would be too.

There is one other possibility - the charging circuit from the trailer tow plug to your battery is defective. This can be easily checked by electrically connecting the trailer to the tow vehicle, starting the tow vehicle's engine, and then checking the voltage across the trailer battery terminals. You don't have to have any electrical equipment on in the trailer when you do this. It should read your alternator output, which would normally be in the range of 14V. If it is below 13V, the tow vehicle is NOT charging the trailer batteries.

And, if you turn on the refrigerator (and it's actually running) if the voltage across the terminals drops to below 12.7V, you are taking more power out of the batteries than they are receiving from the tow vehicle.

I'm interested in what you find out doing this.

- Jack