Truckfridge temp consistency

[Vic Harder]

Just got back from our first camping trip (4 weeks), and while everything worked pretty good, I am confused about the lack of temperature consistency in my new TF130. I am using an Acurite fridge temp guage, and found that the temp would fluctuate from +10* C to 0*C on a given 24 hour period. Mind you, outside temps also varied from 29* to 0* on the same day.

Is this normal????

 

[Backroad Joe]

While I don't claim to be a expert on fridge operation I know my Dometic 3-way does fluctuate with outside ambient temperature.

4 week camping trip.... oh that's nice.

 

[strayDog]

I have the two way compressor 110. Keeps things cold; however I do get the inconsistencies. For the money it seems to have to work a little hard to do it's job. Not sure but I think there is a relationship between the battery voltage and the fridge temp. As the voltage drops the fridge gets less current therefore doesn't run as efficiently. As the solar panels gain on the batteries the current gets stronger the fridge runs more efficiently? The reason I think this is the fridge does work better now that I have 160 and 100 watt solar panels instead of just the 100 watt. Also the fridge fan seems to help.

https://www.amazon.com/Valterra-A10-2606-FridgeCool-11-28-Switch/dp/B002N5W8Q4/ref=sr_1_2?ie=UTF8&qid=1496706650&sr=8-2&keywords=rv+fridge+fan+battery+operated

 

[Vic Harder]

I've got a secondary fan and the batteries never dropped below 85% of their 225 AH capacity.

Yes, Joe, 4 weeks was very nice, and STILL went by too fast!

 

[JaSAn]

The best way I have found to keep temps consistent in a refrigerator is to keep it as full as possible. Air has a very low thermal capacity so it changes temperature rapidly and forms gradients easily.

To see what variance the regulator has put your temp sensor right next to it.

To keep gradients from forming small 1" muffin fans work well to mix the air inside the refrigerator.

IMO voltage should have very little effect on inside temperature (until it gets below 12 volts at the compressor). Unless your refrigerator is running constantly it should hold temperature at the setting of the regulator ± variance. It might run less efficiently but it shouldn't change the characteristics of the regulator.

jim

 

[Vic Harder]

Jim,

Which "regulator" are you referring to? I had my temp sensor in various places in the fridge to figure this out (4 weeks is a good long time for experimenting). The fridge was usually packed. We had water bottles (and after shopping trips, beer!) to take up space not occupied by food products.

Temp was consistently colder at the top near the freezer, and varied in sync with the outside temps. Thus 10*C inside when 28*C out and 0* inside when 0* inside the camper. Frustrating to have the veggies and fruit freeze up overnight!

Vic

 

[Casa Escarlata Robles Too]

Vic There is a "new" member Sean Moore "Truck Fridge".
He posted some info on the Truckfridge.
He is a manager there.
You might PM him for some answers.
Frank

 

[JaSAn]

Jim,

Which "regulator" are you referring to? . . .

Temp was consistently colder at the top near the freezer, and varied in sync with the outside temps. Thus 10*C inside when 28*C out and 0* inside when 0* inside the camper. Frustrating to have the veggies and fruit freeze up overnight!

Probably should have called it the thermostat, the box with a knob on it that you set how cold you want the refrigerator. This is probably where the temp sensor is.

In these small refrigerators the evaporator (the tubing that absorbs heat) is packaged in the freezer housing, so if it is not surprising that the temp just below the freezer is at 0º C (if the thermostat is set to keep the freezer at < 0º). My refrigerator has a drip pan under the freezer that gives some space (~ 1") and a barrier to the dropping cold air. Two added small muffin fans circulate the refrigerator air to reduce the temperature gradient to almost nothing.

My refrigerator (an old Norcold) takes at least 24 hours to stabilize to ambient temperature with no power, so I am not sure why your's should get below set temp so fast. Refrigerators cannot add heat so they will eventually get to ambient it the temperature outside is below what you set your thermostat at. IMO it should take more than 8 to 12 hours.

jim

 

[PaulT]

--snip--
Frustrating to have the veggies and fruit freeze up overnight!
Vic

+1 on keeping fridge full.
We carry a small cooler that we use to prechill beverages with ice after purchase. After beverages are cold, we transfer them to fridge as space is available. Use remaining ice in cooler to keep fruits & veggies cold if you haven't dialed in the fridge temp. We consume beverages from cooler first to avoid opening fridge.

Use Sharpie to mark fridge thermostat dial in three places. One for preferred temp, the second for max safe temp when battery is running low, & third at freezing. We still monitor temp but marks get us very close.

We also keep several blue ice packages in freezer of fridge primarily for thermal inertia. We use these, when needed, to keep small cooler cold after ice melts if we still have perishables in cooler. We refreeze these when driving, hooked up to shore power, or in abundant solar.

Paul

 

[Vic Harder]

Two added small muffin fans circulate the refrigerator air to reduce the temperature gradient to almost nothing.


jim

How do you power these muffin fans? How small?

 

[Wandering Sagebrush]

Vic, there are some small fans sold in RV/camping stores that use 2 D cell batteries. They seem to work. I think I paid about $20 for it. Way too much for something that simple, but there doesn't seem to be other sources.

 

[JaSAn]

How do you power these muffin fans? How small?

I use two 30mm, 12V muffin fans. Being adventurous (or lazy) I drilled a small hole in the side of the refrigerator to snake the leads through (its just plastic, hard foam, and metal skin), filled the hole with spray insulaton (get the non-expanding kind) and wired it to the same circuit as the external frig exhaust fan. They draw 1.6 AH/day each. If you want you can power them from the line coming in to power the thermostat, I just didn't want to take mine apart to find internal power.

https://www.amazon.com/TOOGOO-3010S-0-06A-Brushless-Cooling/dp/B008P72JWM/ref=pd_sim_147_1?_encoding=UTF8&pd_rd_i=B008P72JWM&pd_rd_r=T8ABGZ3CM176775XFHXP&pd_rd_w=R41dX&pd_rd_wg=LqLHs&psc=1&refRID=T8ABGZ3CM176775XFHXP

jim