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Protagonist · 07-12-2012, 08:09 AM

Quote:

Originally Posted by ZoominC6

Why do we men feel, at times, we need to reinvent the wheel?

Because the wheels we've seen aren't good enough, and we're all convinced we can invent a better one.

Alternately, because we can't ask for directions and so can't find the place where they sell pre-invented wheels.

SmokelessJoe · 07-12-2012, 08:28 AM

Steve Jobs might have been a master at Keeping It Simple but he wouldn't have stood still for the worn out Ain't Broke maxim.

He was a master at giving us what we didn't know we didn't have.

Sergei

SmokelessJoe · 07-12-2012, 01:00 PM

Just to add some Real Word experience to the subject of the thread:

I am passing through Toronto, enroute Newfoundland, and left the rig on a shopping centre lot last nite at 5 pm, the LG 110v household fridge left powered by the inverter.

I returned today at noon, 19 hours later. The fridge was still at 38F and the batteries at 12v. The electric jack sounded normal when I hitched up.

So I don't know yet just how long the batteries can maintain this fridge but it is obviously a good long time, longer than most enroute jumps between shore power.

Sergei

Skater · 07-12-2012, 01:40 PM

Quote:

Originally Posted by duggie

Hi everyone, Woosh-you jumped to the wrong conclusion, there is no owners manual, it's a 1959. Take your opinions and jump somewhere else.

How pleasant.

HansenClan · 07-24-2012, 07:44 PM

We have a 65 Overlander, and I have never been able to keep the pilot lit on our original refrigerator while driving? I run it on power before we leave, light it before we hit the road, and by the first stop, whoala, no pilot...Any tips and or hints?

drboyd · 09-30-2012, 10:27 AM

Well, we're talking two different kinds of refrigeration here.

The propane/120V units are absorption cycle, which is great if all you have a bulk energy source, like 120 VAC or propane. They are ridiculously inefficient, using some like 2 BTUs of heat to produce 1 BTU of cooling - that's why trying to run them off a battery is a bad idea.

The LG unit is a Carnot cycle, with a compressor and the like. It runs only on electricity, and uses probably on the order of 1/2 a BTU to produce a BTU worth of cooling. If all you have is electricity, this is the way to go. They're obviously a lot safer, too.

drboyd · 09-30-2012, 10:30 AM

Quote:

Originally Posted by HansenClan

We have a 65 Overlander, and I have never been able to keep the pilot lit on our original refrigerator while driving? I run it on power before we leave, light it before we hit the road, and by the first stop, whoala, no pilot...Any tips and or hints?

As a professional firefighter, you're probably intimidating the flame.

Seriously, do you still have the removable shield around the burner and the little slidy door thingy at the pilot lighting hole? You may be getting enough airflow while you're driving to blow it out.

Skater · 10-01-2012, 06:08 AM

FWIW I did actually try this on one of our trips. It was when we were going to the Outer Banks, during which we go through a tunnel that requires the propane to be off. It basically worked, with a couple notes:

1. We have a large solar system atop the trailer.

2. However, it was overcast and we hit some rain that day.

3. The batteries were run down pretty far when we got to the campground. This didn't bother me - we really should "use" those batteries more than we actually do; they'd probably last longer if we did. We have three batteries in ours.

I'd do it again, but only for the shortest stretch possible. I wouldn't make an extra stop to switch back to propane, but I would switch back at the next planned stop. As was theorized above, there just wasn't enough power to keep the batteries charged. (Of course, had it been a sunny day, the equation would be different for our trailer. They'd probably still get run down, but not as quickly. On the other hand, if it's overcast, you probably don't need to worry as much about the fridge in the first place.)

Phoenix · 10-01-2012, 10:08 AM

The following link has info on the Frio Insulin Wallet and related products. Several testimonials appear to indicate that this works well for backpackers and campers:

FRIO Diabetic Insulin Cooling Cases Buy From Our Authorized US Distributor

Note: I have no affiliation with Frio or Cooler Concept. I found this site in an Internet search for ways to store insulin while traveling. There may be other products that use evaporative cooling to maintain proper storage temperatures for insulin that work better and/or are cheaper.

Ronman · 07-07-2014, 09:19 PM

So as I am reading through these comments, I assume that the refer will not work on electricity while traveling and if I want to keep my stuff cold, I need to use propane mode?
Than you in advance.

Ron

SSquared · 07-29-2014, 09:04 PM

I'm chiming in with my recent experience.

I have a 2013 25FB Flying Cloud. The fridge is a Dometic RM3762. The 120 volt heating element in the fridge is listed as being a 325-watt version.

I just upgraded my trailer with 435 watts of solar panels on the roof, an inverter, and a pair of group 27 batteries, for a total of 200 amp-hours of battery capacity.

When I turn on the inverter and the fridge turns on its electric heater, the inverter draws 31 amps (That's 372 watts at 12 volts). The solar panels put out about 25-26 watts at mid day under a clear sky, in northern areas such as Washington state. So the solar can't run the fridge by itself. But when I start my car, the car provides enough power that it makes up the difference. I have even seen the system put a couple of amps of charge into the trailer batteries when the fridge is on, the sun is out, and the car is running.

When traveling, I find that I can run with the fridge on and end the day with my batteries fully charged, as long as the day ends around 4:00 or so (and the sun is out). When I extend the traveling day to 5:00 or 6:00, I find the batteries are down maybe 10 or 20 amp-hours by the end.

I don't think this would work very well in the winter.

I believe the fridge cycles on and off, which gives a chance for the batteries to recover some charge, but I don't know what the duty cycle is.

I think it is safe enough to run the fridge on propane when traveling, but I do think running on electric is viable under good conditions, IF you have a big enough solar system.

TouringDan · 07-29-2014, 10:32 PM

Quote:

Originally Posted by SSquared

I'm chiming in with my recent experience.

I have a 2013 25FB Flying Cloud. The fridge is a Dometic RM3762. The 120 volt heating element in the fridge is listed as being a 325-watt version.

I just upgraded my trailer with 435 watts of solar panels on the roof, an inverter, and a pair of group 27 batteries, for a total of 200 amp-hours of battery capacity.

When I turn on the inverter and the fridge turns on its electric heater, the inverter draws 31 amps (That's 372 watts at 12 volts). The solar panels put out about 25-26 watts at mid day under a clear sky, in northern areas such as Washington state. So the solar can't run the fridge by itself. But when I start my car, the car provides enough power that it makes up the difference. I have even seen the system put a couple of amps of charge into the trailer batteries when the fridge is on, the sun is out, and the car is running.

When traveling, I find that I can run with the fridge on and end the day with my batteries fully charged, as long as the day ends around 4:00 or so (and the sun is out). When I extend the traveling day to 5:00 or 6:00, I find the batteries are down maybe 10 or 20 amp-hours by the end.

I don't think this would work very well in the winter.

I believe the fridge cycles on and off, which gives a chance for the batteries to recover some charge, but I don't know what the duty cycle is.

I think it is safe enough to run the fridge on propane when traveling, but I do think running on electric is viable under good conditions, IF you have a big enough solar system.

I think it may work fine in winter. Your solar may not be contributing much, but remember that it is winter and your fridge won't need to run much to stay cold.

Dan

SSquared · 07-30-2014, 12:37 AM

Good point, Dan.

duggie · 07-30-2014, 10:16 PM

Hi Ssquared, I didn't think of solar panels. Great idea. Do they conform to the top okay? How did you attach them? Thank you, doug.

J. Morgan · 07-30-2014, 10:38 PM

Fwiw,,,, I have a 10cuft residential fridge, my tow vehicle easily runs the fridge and fully charges my batteries simultaneously.

Maybe solar might keep up with a residential style fridge.

swede0030 · 07-31-2014, 05:03 AM

I have always had propane flame out/relight problems at hwy speeds in crosswinds. The flame goes out and the auto relight tries about 5 times and then reads error message. The freezer must be packed with ice to insure max. temps. towing with propane in play. I read that propane is approx. 30% less efficient than 110v AC, so it seems the only way to tow would be with an AC inverter connected to the refrigerator. Is this not the easiest way to improve cooling in high temps. during summer months? Why aren't we all doing this?

Skater · 07-31-2014, 08:30 AM

Quote:

Originally Posted by swede0030

Why aren't we all doing this?

For the reasons that were listed in the thread already - it requires fairly substantial battery capacity and solar (or a better charging system from the vehicle) to recharge them while on the road.

Setting aside the residential fridge idea (because we occasionally boondock), the 31 amps quoted means your battery/batteries won't last long.

Ronman · 08-09-2014, 06:19 PM

P

Sent from my iPhone using Airstream Forums

SSquared · 08-09-2014, 06:37 PM

Quote:

Originally Posted by duggie

Hi Ssquared, I didn't think of solar panels. Great idea. Do they conform to the top okay? How did you attach them? Thank you, doug.

Hi Doug,

Sorry, I only just now saw your question.

My solar panels are the AM Solar 100 and 135 watt models. They are rigid panels. They are mounted on stand-up mounts at each corner, giving an inch or two of space between the roof and the frame of the panel. They are attached with special 3M "Very High Bond" tape, plus Sikaflex sealant.

I did not personally install them; Lewster & his son did.

You can get flexible panels that you glue flat to the roof. That's not what I have. I think my panels are mounted low enough that they don't provide too much more wind drag, and don't look too bad. There are three on the front and one at the back. The wires run down the back of the fridge.

SSquared · 01-24-2015, 05:28 PM

Here is a belated update.

We made our last trip of 2014 during the last week of September, in Colorado. We still did OK terms of the battery state of charge at the end of a travel day when running the fridge from the inverter, though I think it worked better in the summer.

The days had highs near 80, usually with sun in the morning, clouds and some rain in the afternoon. It was warm enough that the fridge needed to run regularly, though obviously less than in summer heat (I don't have a way to track the fridge on/off times). The lower sun angle reduced the power we got when we did have sun--the highest output we saw on this trip was 21 amps.

So on one travel day, we were at -14 amp hours when we stopped at 6PM. On another day, we were at -21 when stopping at 4PM.