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-   -   Simple Survey on Fridge Performance While on Propane (http://www.airforums.com/forums/f404/simple-survey-on-fridge-performance-while-on-propane-169937.html)

AlinCal 08-06-2017 09:31 AM

Maybe Airstream should give one to every new Basecamp buyer.

Bborzell 08-06-2017 09:41 AM

Just returned from a 6,857 mile shakedown cruise of our Basecamp.

I'm going to write up overall impressions after we unwind and things settle down but I thought I would quickly summarize our fridge experience.

After getting the "added fan" fix at our dealer a few days prior to departing and the current heat deflector/insulation fix at Airstream while on the road, my post Jackson Center conclusions are as follows:

1. Up to about 83-84 degrees outside temp is about all the fridge can handle while driving on propane before the box starts rising above the maximum food safe level of 40 degrees.

2. The low to mid 80 degree outside temp limit for driving does not seem to be quite as limiting while parked on propane. We parked in temps up to 90 after the Jackson Center fix and were able to maintain sub 40 (actually 39) degrees temps in the box. Going to 120V dropped the box to as low as mid 30s.

3. Following the Jackson Center mods, the fridge maintained a upper limit box temp of 37-39 degrees consistently while on 120V power.

One variable that I was unable (more like unwilling) to control for was humidity. In general, I think that higher humidity does introduce some greater difficulty in attaining/maintaining food safe temps, but I cannot be sure how or when that effect was significant.

The propane shroud does not seem to hinder cooling while on 120V. In fact, one bit of info that might be key to pinning this thing down is that the top vent exhausts considerably higher temp air (to the touch) while parked on propane than it does while parked and plugged in. This leads me to believe that the open flame provides just enough added cabinet heat to throw the cooling into fail mode when the outside temp rises above the mid 80 degree mark. It might be that the delta between success and failure while on propane is the few added degrees that the open flame provides to the inside of the cabinet.

switz 08-06-2017 10:46 AM

These last few comments makes it apparent Airstream must NOT have tested this refrigerator in the Southwest summer heat with a prototype Base Camp. They would have discovered the cooling issue and had to address it before releasing the trailer.

At this point, the trailer design is not fit for sale for the purpose stated as hot weather is to be expected in the lower 48 in the summer and the purpose of the refrigerator is to keep food at a safe temperature in all conditions that would reasonably be expected in the summer.

OTRA15 08-06-2017 11:18 AM

Thanks for the update, Bborzell. Digital meat thermometers (and similar ones used by HVAC contractors) are pretty inexpensive. You could stick the straight probe end in the vent louvers, and get a real-time temp in about 10 seconds. This would be very helpful data to have IMO.

What are the temps at the intake vent, and also at the exhaust vent? The change in temp is a very important measure of how well the unit is cooling.

In the realm of air conditioners, I think this is called the temperature Delta, and most simple A/C systems call for 20 degrees Fahrenheit +/- as a generally-agreed-upon Delta to aim for. In other words, if a room starts at 80, the air being exhausted by the A/C should be 60. As the room cools down, the exhaust air should also drop.

Knowing the Delta temp drop for the BC fridge would be great to track IMO.

Cheers,

Peter

OTRA15 08-06-2017 11:21 AM

Quote:

Originally Posted by switz (Post 1989341)
These last few comments makes it apparent Airstream must NOT have tested this refrigerator in the Southwest summer heat with a prototype Base Camp. They would have discovered the cooling issue and had to address it before releasing the trailer.

At this point, the trailer design is not fit for sale for the purpose stated as hot weather is to be expected in the lower 48 in the summer and the purpose of the refrigerator is to keep food at a safe temperature in all conditions that would reasonably be expected in the summer.

Sorry to say that these conclusions appear to be inescapable IMO.

:angry::wally::angry:

MrKenmore 08-08-2017 12:18 PM

We called AS today and spoke to Jeremy. No TSB issued yet. Official fix is still in the works.

Thinking about the solution, it appears a a marine style fridge may be the best answer (AC/DC, no LP). I just don't know how they will cure all the venting (or lack of) issues with an LP/electric fridge. A marine style fridge would likely warrant a second battery which we fortunately have the room for. I know this was mentioned previously in the thread. Is this a viable option? I do not have much experience with marine fridges.

switz 08-09-2017 12:22 AM

We love the Vitrifrigo marine fridges we installed in our 2015 23D International Serenity (model DP150L) and the 2014 31' Classic (model DP2600). Food is the proper temperature all the time. The fire hazard of the ammonia based equipment is gone.

We have a single 300 amp-hour lithium battery mounted in front of the street side wheel well under the sofa for our 23D. It weighs less than the two stock lead acid batteries (84 pounds) we removed from the front battery box. We do have five 100 watt AM Solar panels the roof.

We have a single 600 amp-hour lithium battery under the front sofa of our 2014 31' Classic that at 168 pounds weighs a lot less than the four 96 pound Lifeline 6Vdc 300 amp-hour GSM batteries we had on the tongue in custom stainless steel enclosure. We have nine 100 watt AM Solar panels on the roof.

InterBlog 08-09-2017 07:40 AM

Quote:

Originally Posted by MrKenmore (Post 1990517)
.... it appears a a marine style fridge may be the best answer (AC/DC, no LP). I just don't know how they will cure all the venting (or lack of) issues with an LP/electric fridge. A marine style fridge would likely warrant a second battery which we fortunately have the room for. I know this was mentioned previously in the thread. Is this a viable option? ....

As the other poster above noted, all indications right now are that the Vitrifrigo is a good choice. Pardon me if I linked this same blog post previously, but here is a description of how we swapped out our Dometic RM2351 for a Vitrifrigo C115IDB4-F. The Vitrifrigo is a slightly larger fridge in terms of cubic feet, so we did have to do some cabinet surgery.

We just did this mod a few weeks ago so I don't have good ground truth on power consumption in our context, but yes, you'll have to make power mods of some kind. One battery won't support it.

uncle_bob 08-09-2017 07:45 AM

Hi

You can run a typical RV LP fridge for weeks on the gas bottles. The number of batteries to accomplish that with a 12V fridge is massive. If you run it off of your solar, that assumes you have sun *and* don't have something else to do with the power.

Is this a real issue? Take a look at all the people complaining about flat batteries after "just a little time camping". Toss in a significant continuous load and ...yikes ....

Some math:

Your "typical" battery in a small trailer is around 70AH. You can get 35AH out of it before you get into "don't do that" territory. A one amp average load will run it down in about 1.5 days. Even if you dedicate a battery to the fridge, that's not very long. Does this or that fridge average more or less than one amp? How hot is it out? What did you put in the fridge? How often do people open the door? How well ventilated is the "hot" side? How small is it inside (for a fixed outer volume)? How cold do you have it set? You don't need to cover the usage of "frugal Bill" who is very careful. You need to cover "careless Bob" who is in for a beer every 5 minutes :)

Support it with solar sounds like a good idea. A 100W panel at 80% for 8 hours a day will give you 640 WH. 1A at 12V for 24 hours (same assumption as above) is 288 WH. Roughly speaking, on a "charge in one day, use for two days" basis, a 100W panel will do a bit more than keep the battery up. Park in a bit of shade .... not so much. Now you are ruling out all those nice shady camping spots in the forest.

This *does* sound like pretty bad for 12V fridges. They are great gizmos. They do a wonderful job. They have a lot of practical advantages over an LP system. The *only* issue with them is needing electricity. Compared to the factory systems on any of these small trailers (any brand / model) that electric demand is significant.

So, bottom line: I don't think you will see mechanical refrigeration in small trailers from the factory.

Bob

ijustlee 08-09-2017 12:33 PM

If I had a Base Camp I'd make a short video documenting how the fridge doesn't work. Then I'd make an appropriate chimney up to the roof out of cardboard and duct tape and document how the fridge works that way. I'd tow the trailer to the place I bought it, park out front and demand that Airstream make the fridge work right by providing an appropriate chimney made out of clear or tinted acrylic or whatever is the best looking material. A refrigerator that you can't boon dock with sort of defeats the reason to have a BC in the first place. Having to run a fan to make your fridge work would have me thinking of a different brand of trailer.

Rzr1999 08-09-2017 01:09 PM

Quote:

Originally Posted by ijustlee (Post 1991014)
If I had a Base Camp I'd make a short video documenting how the fridge doesn't work. Then I'd make an appropriate chimney up to the roof out of cardboard and duct tape and document how the fridge works that way. I'd tow the trailer to the place I bought it, park out front and demand that Airstream make the fridge work right by providing an appropriate chimney made out of clear or tinted acrylic or whatever is the best looking material. A refrigerator that you can't boon dock with sort of defeats the reason to have a BC in the first place. Having to run a fan to make your fridge work would have me thinking of a different brand of trailer.

I'm not buying one until there is a fix. Also going to look at RPODS, Winniedrops, and Rockwood GEOPro (under 3,000 pound trailers) I prefer the airstream, but too many issues with the fridge.

nickclifford 08-10-2017 12:37 AM

Very interesting thread, must be very upsetting to be on vacation in a beautiful and expensive airstream with no way to keep food chilled, even worse my, Sauvignon Blanc ! This has me thinking now, I need to replace my 40+ yr old domestic (which still cools quite well btw) ... what to replace with that wouldn't need fans running etc and that actually works !

xrvr 08-10-2017 05:10 AM

[QUOTE=Gail Miller;1988042]Thanks Peter. I'll stop with the updates and wait for AS to come up with a solution for the Please don't stop with the updates just because someone who doesn't own a base camp suggests it. I think you've done well.

OTRA15 08-10-2017 07:09 AM

Quote:

Originally Posted by avionstream (Post 1991393)
. . . Please don't stop with the updates just because someone who doesn't own a base camp suggests it. I think you've done well.

Which was clearly stated a few posts later, for the record.

:wally:

Quote:

Originally Posted by OTRA15 (Post 1988073)
. . . it was not my intent that you stop updating everyone.
. . .
. . . I hope you will continue to update us, as you have been a true champion in seeking to have Airstream, and Thor the parent corporation, fulfill their duty to all Airstream owners to make things right with the Basecamp.
. . .


Bborzell 08-10-2017 07:38 PM

Took a few days of from taking temp measurements.

Last night I turned the fridge on while running 120V. By morning today it was at 39 degrees. As the temp rose outside, so did it in the box. By 5 PM it was 91 outside and the box had risen to 48.

Picking up on Peter's suggestion, I decided to quantify the temp being exhausted out the top/front vent. Using a very accurate Thermapen cooking thermometer, I got an exit reading of 113.5 degrees. This with an outside temp of 89 degrees and a box temp of 48.

Tonight I will switch to propane and run the same measurements tomorrow.

OTRA15 08-11-2017 04:44 AM

Thanks for the update. Taking a few days off is understandable . . .

:)

On your 5 PM reading of 48 inside the fridge with outside air at 91, was the front of the trailer in the direct sun during the day? Solar gain on that dark plastic propane cover will act like a real heat sink, almost a radiant heater right next to the fridge. I forget, is there an intake air vent for the fridge's cooling system? Measuring this intake air temp would also be good if so. The air trapped behind the (solar heated) propane cover may actually be quite a bit hotter than the ambient outdoor temp IMO.

Is there any way you can also stick the thermometer's prob inside the cabinet which houses the fridge? It may be like a little warming oven, in fact, making the task of cooling things down all the more difficult.

Good luck!

Peter

Bborzell 08-11-2017 10:40 AM

Quote:

Originally Posted by OTRA15 (Post 1991937)
Thanks for the update. Taking a few days off is understandable . . .

:)

On your 5 PM reading of 48 inside the fridge with outside air at 91, was the front of the trailer in the direct sun during the day? Solar gain on that dark plastic propane cover will act like a real heat sink, almost a radiant heater right next to the fridge. I forget, is there an intake air vent for the fridge's cooling system? Measuring this intake air temp would also be good if so. The air trapped behind the (solar heated) propane cover may actually be quite a bit hotter than the ambient outdoor temp IMO.

Is there any way you can also stick the thermometer's prob inside the cabinet which houses the fridge? It may be like a little warming oven, in fact, making the task of cooling things down all the more difficult.

Good luck!

Peter

I don't see an easy way to measure the temp in the cabinet, but my observation this morning might render that attempt moot.

On propane since 7 pm yesterday and the box temp is 37.6. The upper exhaust vent is putting out 113 degrees with outside temp of 76 (it will be interesting to see how high the exhaust goes up after the shroud sits in the sun at 90+ degrees later this afternoon). The front of the shroud is currently in full sun and has a surface temp of 84; much less than the 113 coming out of the exhaust vent.

But, here's the kicker: The lower intake vent is actually discharging air rather than drawing air in. I can feel hot air emitting from the intake at 105 degrees. This suggests to me that the heated air inside the cabinet is high enough to create positive pressure not only at the exhaust point, but at the lower intake point. Once the cabinet temp starts to increase, there is simply no way for the intake vent to allow cooler air in; there is too much internal cabinet pressure from heated air.

Bob

FricknFrack 08-11-2017 11:14 AM

Just dropped off my BC at the AS dealer for the refrigerator fix. They told me they are 4th largest BC seller in the country and EVERY BC that has left their dealership has had the exact same problem with the refrigerator. They said AS HQ has been denying the problem all along, although the warranty dept at HQ acknowledged the issue to me on the phone. They say their fix with fans and better insulation around the box has fixed every one of their BCs - will see...

Troutboy 08-11-2017 11:35 AM

Quote:

Originally Posted by Bborzell (Post 1992089)
I don't see an easy way to measure the temp in the cabinet, but my observation this morning might render that attempt moot.

On propane since 7 pm yesterday and the box temp is 37.6. The upper exhaust vent is putting out 113 degrees with outside temp of 76 (it will be interesting to see how high the exhaust goes up after the shroud sits in the sun at 90+ degrees later this afternoon). The front of the shroud is currently in full sun and has a surface temp of 84; much less than the 113 coming out of the exhaust vent.

But, here's the kicker: The lower intake vent is actually discharging air rather than drawing air in. I can feel hot air emitting from the intake at 105 degrees. This suggests to me that the heated air inside the cabinet is high enough to create positive pressure not only at the exhaust point, but at the lower intake point. Once the cabinet temp starts to increase, there is simply no way for the intake vent to allow cooler air in; there is too much internal cabinet pressure from heated air.

Bob



Bob, what you are seeing is air short circuiting, the reason that both switz and I made the baffle and closed off portions of the exit vents.

If hot air is being forced out the lower vent, that also means that same hotter air is crossing the soils and won't remove as much heat.

If you provided pictures, maybe we could help you design a baffle?

Or maybe ask the dealer to do something with a baffle?

OTRA15 08-11-2017 12:30 PM

Thanks Bob for quantifying what is going on -- pretty much what everyone's worst fears were -- suggesting that at a minimum any fix must include one or more baffles and maybe multiple fans.

Re-designing the Basecamp to get the fridge over to one side, with a flue through the roof, would of course solve the problem completely, but who wants a perfect solution?

:blink:

The Bandaid-after-Bandaid approach is sure testing everyone's patience and faith in Airstream and Thor, the parent corporation.

Thanks again for the data.

Peter

PS -- Adding a fan or two will change the need for battery power while boondocking of course. A second or third battery and solar panels would probably be a good (free?) upgrade IMO.


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