Homemade Freezer Thermometer

In the TT we leave some things in the refrigerator. It is a absorptive two-way which uses 120VAC when available and propane/12VDC if AC power isn't available.  We leave the TT at a site unattended sometimes for a couple of weeks. But we don't empty the refrigerator and it is in the AUTO mode. We take all meat items or high spoilage stuff out when we leave, but condiments, bread, peanutbutter, soda, wine, frozen veggies, cheese, etc. are left cold.

We are counting on the refrigerator switching from 120VAC to propane/12VDC in the event of AC power loss. That has worked fine and will work as long as the battery and propane are available. However, there is always the possibility that something will go wrong.

We use a simple memory thermometer for the freezer. We filled a 3 ounce plastic cup with water and placed it in the freezer. We also placed a quarter in the freezer. This prepared the thermometer.

Several hours later, we removed the frozen cup and quarter. We placed the quarter on top of the frozen water. Then we put it into the freezer.

If the freezer begins to thaw, the ice will turn to slush and the quarter will sink into it. On return to our TT we simply check the freezer. If the quarter is resting on top then we know the freezer temperature has never warmed above 32F.

Oops, Had an exterior hinge latch failure and repair.

Discounting the shakedown issues, after 19,000+ miles we experienced a Roadtrek failure.

One of the door catches which holds a rear compartment door in the open position wouldn't spring shut. The catch is apparently SS, but this spring was a lower grade of steel. Interesting, because the failure only occurred on one of two hinges. This highlights the problems all companies face with suppliers. On the failed catch the spring rusted through.

I was able to do some research on the internet and found what appeared to be the identical hinge. I purchased two for $7.49 plus shipping and tax. [Current price is $7.69 per pair]. On receipt the new hinge looked to be a perfect fit, with identical dimensions. I drilled out the pop rivets that held it in place. I was pleased to see that RT had installed a thin layer of silicone seal behind the hinge. Great detail, guys! I applied a thin layer of 30 year silicone and attached the new hinge with 3/16 inch dia. aluminum pop-rivets, which matched the old. Voila' all good! And, I've got a spare hinge for the other side of my 210P.

New Latch, Closed

New Latch, Open

Old Latch after removal, showing rusted spring

RV Refrigerator Tweaks

It’s getting warm and I see more and on the social websites about complaints or issues about RV refrigerator performance. There are some things that one can do without voiding warranties or spending serious cash.

What type of refrigerator? Some of the newer rigs have 120VAC compressor refrigerators (residential models) with big batteries and a large inverter (12VDC in/120VAC out) to power the refrigerator when trekking down the road and off of 120VAC shore power. Our 5th wheel (HB#3) has such an arrangement. The TT (HB#2) has a larger absorptive refrigerator with separate freezer and refrigerator compartments. We don’t trek in it so it runs on 120VAC.

Our Roadtrek (RV #1)) also has an absorptive refrigerator. It’s a single door model 5 cu. ft. We do trek in it and so we do run it under a variety of temperature extremes, and on 120VAC as well as propane/12VDC battery. It’s a good size but not as large as the one in the TT. We use the Roadtrek refrigerator to transport initial food to the summer camp (HB#2) and of course when on our treks (longest to date was 110 days). The refrigerator has performed well, but we decided to make some modifications to help it out under high ambient temperature conditions. This post is primarily a consequence of our experiences in the Roadtrek with treks from 2 weeks to 110 days.

There are some things to know about the absorptive type of refrigerator. Adapting to what we’ve learned makes our treks better. ‘Better” as in more successful or easier. I suspect some of our lessons learned would be helpful with any style or model refrigerator.

IMHO having a good time means learning to live within limitations. That might be our financial means, our time constraints, or the limits of the available technology. One can resist or one can adapt. It’s all a matter of choice. I prefer successful treks and so I learn and adapt.

1. The absorptive type of refrigerator is slow to cool. That means turn it on and give it some time to reach 45F. If the refrigerator is 90F when you turn it on, don’t expect instant frost. Sounds simple, but you would be surprised what people expect. It also means put cold things in it to give it a boost. Put warm things in a warm refrigerator and one can expect soured milk. What can we do to avoid this? Start up the refrigerator several hours before first use. How early? The warmer the refrigerator is when you start it up, the longer it will take to chill. Use common sense. As an aid we also put a large, frozen ice pack in the freezer when we pack it for a trek. That works very well. See the photo.

2. On hot days don’t park with the sun striking the side of the RV that the refrigerator is on. The additional heat from the sun is sure to create efficiency problems for absorptive refrigerators. We travel with a triangular sun sail to shield the RT from the hot sun.

3. Do what one can to help the refrigerator. We load it up with fully chilled goods before we trek, and that large ice pack.

4. Once on the road we minimize the bulk addition of warm items, and prefer to add these only in the evening when the ambient temperatures are falling. For example, we only add 2-4 cans of warm soda or sparkling water at a time. When we shop, we put the coldest things in a small cooler, to keep them cold. When we introduce them into the refrigerator there is less “heat shock.”

5. Use an interior fan. There are battery operated ones, and fairly inexpensive wired 12VDC fans. We opted for the battery powered simply because our refrigerator doesn’t have an interior light, or some easy means to get to 12VDC power.

 6. If you are planning on travelling in elevated temperature areas, add exterior, supplemental fans to draw air into the compartment behind the refrigerator. This we decided upon when we experienced the consequences of daytime temperatures consistently above 100F.

Here's the sun sail mounted to shield the front of the vehicle. if the sun was on the refrigerator side, we'd position it to provide shade on that side. 

Adding Refrigerator Exterior Fans

Photo During Construction!

The sun is a beneficial thing in RVs in the winter. Most RVs have a lot of glass, and that surface area loses heat in the winter. So sunshine is a good thing. However, in summer the sun can contribute to discomfort and can interfere with operation of the refrigerator.

When we trek, we sometimes park in full sun and occasionally in partial shade. More often than not we don't get to choose the orientation to the vehicle to the sun or the amount of sun we receive.

On a trek a while back we were in a location where we and a lot of other people were in full or partial sun. The outside temperature in the shade peaked at 103F (39C). To make things worse, the vehicle was oriented so the afternoon sun was full on the side of the vehicle that houses the refrigerator.

Our Class B has a single door Dometic refrigerator. This is the absorptive type, which does not have a compressor. It works well, but is slow to cool from ambient temperatures. It has rear radiators. The radiators are behind the refrigerator and two grills on the side of the RV provide cooling of the radiators via convection. "Cool" air enters the bottom vent, passes through the radiators and the compartment cooling them. It then exits through the upper vents.

On our trek which reached peak temperature of 103F the refrigerator struggled. We weren't alone and a lot of rigs both big and small had similar issues.

We decided to do something about this. Short term, some people put a bucket of ice in their refrigerator. That is not always practical. First, one has to find a source of ice. Second, that bucket takes up interior space, which is precious in a 5 cu. foot refrigerator. Third, the water has to be disposed of. If a covered container is used, as the ice melts it won't slosh around while moving, but otherwise it can get messy.

The other choices we considered included one active and one passive supplemental cooling technique. The passive one was to add a moveable sun shade. However, we usually orient that in such a way as to reduce sun on the front of the vehicle, where most of the glass is. The other was to add electric fans to improve the airflow behind the refrigerator.

Dometic has instruction on how to do this for both single and dual door refrigerators. Here's a link to the single door instruction. Dometic also has instructions on the web for their dual door refrigerators:
Dometic Power Ventilator Instructions

Installing these will vary from model to model and that includes the details of the RV. I chose a location directly behind the upper vent openings. I also installed an simple aluminum strut to bolt the fans to. I used two low power fans and a thermostat mounted on the hot side of the coil. Seems to work well.

18 Months of Improvements [Now at 84 months]

Note:

1. You will find posts elsewhere in this blog for some of these, which detail the actual install and provide further insights.
2. I also have videos detailing some of these as well as treks on my YouTube Channel. Here's a link:   Link to My YouTube Channel
3. If you are a new Roadtrek owner I suggest you consider 1) A power protection device, 2) A water filter, 3) A water pressure regulator, 4) a 750/1500 Watt ceramic heater. All of the other modifications I made were based upon my actual experiences and perceived needs. You should use your actual experiences to be your guides for what you add, or purchase, to your Roadtrek.  
4. Some of the following I'd call "gadgets" and one of these days I'll post a complete list of the gadgets and useful things I've added. 
5. It is my understanding that Thetford no longer makes the Sanicon hose.  (2020). However, Home Depot sells 1-1/4" diameter flexible sump pump hose. I haven't tried it. 
   

Edited to add #15, 16, 17, 18, 19, 20, 21.
Added #23, 24, 25
July 2017, updated #25, added #26"The list goes on."
January 2018 added electric heater info
October 2018 added water meter.
March 2021 Added Sanicon note (item #16)

Originally posted as "18 Months of Tweaks"

Thursday, September 24, 2015

Note: These were all a consequence of our experiences during our first several treks. "Official" outdoor temperatures ranged from 9F to 103F. We completed the first 13 modification in the 18 months of purchase and the first 15,000 miles. We have added modifications #14 and so on in the months thereafter.

This is a brief list of the tweaks or additions to the Roadtrek. I thought it might be useful to list the mods to my 210P. Not that many, actually. Most of these were documented elsewhere on this blog. These are in no particular order. [I'll update this from time to time with more recent modifications.]

1. I added a 50 watt solar panel and solar charger for the AGM coach batteries. This primarily because for the first two winters it was stored in a place which doesn't have 120VAC available and I didn't want to remove the batteries for the winter. I ran the generator about every other week to supplement the solar charge and exercise the generator, weather permitting.

2. Progressive Industries hard wired power and surge protection device with readout mounted in the coach. The device was installed in an exterior compartment with 30A twist-lock connectors for easy bypass or removal. The coach readout does include a bypass select, current, Hz, volts, fault and previous fault readouts. 

Progressive Industries Power Protection Device

3. Improved backup camera - color with transmitter/receiver (no front to back wiring required). This became a necessity when the onboard radio/GPS/monitor died. With a trip about a week away I decided it was expedient to add a second "selectable on" camera and deal with the radio issue at a later time. With Roadtrek's assistance it was determined it was the Scosche intelligent bus controller. To get to it required tearing the entire dash apart. After fixing the power to the radio we decided we like the improved all-time color monitor and camera and use it in traffic situations. 

4. Internal/external temperature monitors. Simple home, battery operated system with a wireless remote mounted in rear storage compartment to monitor outside temperature. The smaller can also be used to monitor the interior temperature of the refrigerator.

Ambient and remote temperature monitor - great for refrigerator

Ambient and remote temperature monitors - the remote is in an outside compartment

5. Improved LED dimmable lighting. Added a 16 ft flexible strip the length of the coach and around the rear. Includes remote control for selection of color and intensity. Wonderful nighttime lighting improvement.

Dimmable LED light strip

6. Outside 120VAC receptacle. This is a "made to fit" heavy duty extension cord permanently routed to the coach battery compartment. When not in use it is unplugged, depowering the outside end. I plug it into the ground fault protected outlet inside the side door when I want to power it up. This became a necessity when I found that many of the 120V auxiliary receptacles at campgrounds don't work; this is because the ground fault protectors are always tripped and won't reset, even with nothing plugged in. So my extension cords for inductive cooking or outside lighting were useless. I didn't want to run them under or through an open door so this was the solution. 

7. Reflectix cut for all windows except the side entry.

8. Moveable sun sail. Usually we put this at the front of the vehicle. Significant improvement to the interior temperature when camping in full sun.

Sunshade and Reflectix

9. Supplemental Portable Electric Heat. We use a 750/1500 watt electric ceramic heater to put a load on the Onan generator. It also heats the interior when nighttime temperatures are below 50F. This allows us to become creative about energy use and is a backup for the heat pump and the propane furnace. Setting it below the thermostat of the heat pump allows for supplemental heat. It is also a great way to exercise the generator. Not really a "modification" but then, one does need a load when running the generator and this is it.

Portable 750/1500 Watt 120VAC electric heater

10. Additional supplemental electric heat. After nights down to 5F I decided I wanted a low wattage heater for the front of the Roadtrek, to help with that large glass frontal heat loss area. Even with Reflectix (R-1.0) a lot of heat is lost. I experimented with a flat panel heater in the travel trailer and it worked very well. We have a 250 watt version for the Roadtrek (about 18x23 inches and 1/2 inch thick). I also have a programmable digital thermostat because the heater only has an Off-On switch. So far this winter (2017-2018) we've avoided the circumstances in which it would be required. Caution: the surface of this type of heater panel can get HOT. Which is why we have not yet used it in the close confines of the Roadtrek Class B.

11. Front fan to distribute air in the front of the vehicle. This 12V rectangular fan with side air inlets sets in the tray above the passenger door and improves the temperature, both hot and cold, via improved air distribution. In the summer, when used with the sun sail and reflectix it makes for a much more comfortable front end of the vehicle, if parked in full sun.

12 VDC fan

12. Finger bump preventer for side door screen. Added an aluminum angle because it was too easy to push against the door to open it and bump the screen when exiting. Doing so would push the screen out of it's mounting.

13. Inductive electric burner. This is an electric appliance and is portable but it has proven to be so handy I included it here. We do a lot of cooking when on the road and when it's hot or warm, cooking outdoors is a natural. We even cook breakfast outdoors using this. [This week I made donuts at our site using a cast iron skillet - Lodge, of course!] The burner works best with cast iron skillets but I do have an iron plate for use with aluminum pans (shouldn't boil water in cast iron, or cook acidic things like tomato soup). To provide some idea of how little propane we use, we filled our propane tank this spring and use it primarily for hot water. The readout currently shows 2/3 full. But, as these readouts are known to be unreliable, we really don't know how full or empty it is.

Inductive electric cooktop with iron heat transfer device
Inductive cooktop requires iron and stainless steel pots do not work

Cast iron griddle on induction electric cooktop

Inductive electric cooktop with cast iron

14. A small propane BBQ. This is another appliance but we prefer to cook outdoors when possible. This keeps the interior humidity lower and ditto for the temperature in summer.We use small disposable (recyclable) cylinders. Not the cheapest approach and the 210P does have a rear connection for a propane appliance. But we usually cook on the exterior passenger side of the vehicle and in the shade of the awning (but not necessarily under it).

Propane BBQ

Preparing a small feast made with the propane BBQ and the induction electric cooktop with cast iron skillet

15. Hockey puck LED tap lights. These are powered by AA batteries and we purchased a pack of five and placed them in overhead compartments.

Battery powered hockey puck light

16. How could I forget? Replaced the standard Roadtrek Macerator dump hose with a Thetford Sanicon 21 ft flexible hose extension for macerator. Thetford #70424. On one of our first treks, the standard Roadtrek dump hose would not reach to the dump point. Had to start and back onto a road to dump. This was my [second] mod to the 210P. It is my understanding that Thetford no longer makes the Sanicon hose.  (2020). However, Home Depot sells 1-1/4" diameter flexible sump pump hose. I haven't tried it. 

Thetford Sanicon macerator dump hose, extends about 20 feet.

17. First thing we added was a Maxx-Air vent cover. We went with the "smoke" color and had the dealer add this the morning we picked up the 210P. Now, I gotta say that on the 210P it is ugly. But, it is really functional. We don't worry about rain, or bugs or bird nests, or forgetting to lower the Maxx Fan cover when travelling, or parked on a bluff when a nasty thunderstorm comes up. 

Maxx Fan cover

18. Added two small fans with thermostat to improve the temperature in the area behind the refrigerator. We had experienced some difficulties, most notably in TX at 100F. Sun load on that side of the vehicle was sometimes a problem.  We can't always find shade or park in the orientation we would prefer to the sun. 

Whisper fans to help cool the Refrigerator compartment

19. Dual control electric blanket. This was a really pleasant addition. We camp in 3-1/2 seasons which means down to zero degrees F. An electric blanket is superior to a sleeping bag because it adds supplemental heat beyond that generated by the occupant. I'm a long term "ground camper" and so I do know all of the alternatives. But if one wants their spouse or anyone who is not an outdoors woman (or outdoorsman) to be comfortable when the outside drops below 32F, I suggest this approach.

Marketing photo of the electric blanket - Ours has dual controls

20. I added a custom screen to the passenger side window to improve ventilation. This is attached with magnets. 

Side window screening

21. I added custom screens to the furnace outlet, hot water heater grill and the refrigerator openings. These are held in place with magnets. For the refrigerator I epoxied steel washers to the inside of the cover. The magnets adhere to the washers. The purpose of this is to prevent 'critters' of any kind from moving in. 

Covers for furnace vent

22. Last year (2014) we spent extended periods of time in areas with very hard water. I do have a water pressure regulator and a filter on the RT. However, I noticed deposits forming on the faucets and then the check valve at the city water inlet stuck in the "open" position. I purchased an "On-the-Go" portable softener and it works well. However, that's one more thing to carry!. I did clean the deposits from the check valve by removing the screen at the inlet, and then with a short piece of hose I poured vinegar directly into it and with the hose full I let it set for a day, then removed the hose and pushed the check valve in, added more vinegar and so on. I did this repeatedly and it cleaned up the valve and it works fine.

Portable water softener

23. At 36 months I replaced the coach batteries. These simply didn't provide the capacity as published. This didn't seem to be a problem as we seldom "boondocked" for more than a day off of shore power. However, in the second year we spent longer periods off power and noticed that the batteries didn't seem to provide the expected duration of power. The status LEDs would indicate "C" for charging when on shore power or solar and then "F" for full charge when running on coach battery power. I measured the voltage at the battery terminals and began comparing to a charge table for AGM batteries. The "L-F-G-C" indicator would indicate "G" or Good when the battery was at 60% DoD (depth of discharge) or lower. While AGMs can be discharged 80%, it is my understanding that repeatedly discharging below 50% will shorten the life significantly. I decided to put a better battery monitor on my list. See item 25. I measured the amperes draw and concluded the battery terminal voltage was dropping more rapidly than expected. We probably were getting about the equivalent of a 120Ah battery, and I assume the batteries were nearing end of useful life. 

Approximately 220Ah AGM batteries

24. Purchased a battery monitor with shunt. I am also considering adding a disconnect for the coach batteries, but I have concluded that would not be easily accomplished. Shortly after purchase of the Roadtrek I added a portable 50W solar panel and controller to charge these batteries. However, there are now times I store the RT and disconnecting the coach batteries is probably the best solution if I don't want to use the solar panel.  I've assembled the case for the meter, run the wiring and installed a shunt. Next will be the actual installation (July 2017).

Digital voltmeter-ammeter for coach batteries.

25. I got tired of struggling to attach the fresh water hose. It took two hands to unscrew the plastic cap to the plastic fitting inside the compartment. After some research I purchased a fitting of brass which I attached to the fresh water inlet. As a bonus it includes a ball valve. I attached a small length of hose to this, which I never remove. I can now more easily remove the longer length of hose. The photo includes "after" and "before" views, but without the short piece of hose attached.


26. Water Meter.  Helpful when filling the inside tank, which has approximately 10 gallon capacity.

Water meter for hose

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