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Thu Apr 23, 2020 11:39 am

Sorry if this has been posted before but I could not find anything in a search.

I think I have seen someone with a digital thermostat for a Truck Fridge. Ideally one that is exterior to the fridge and gives the inside temp readout. I am not thrilled with the stock temperature dial and would like to go digital if it is available.

Thanks!

Thu Apr 23, 2020 3:09 pm

Think Marine fridge systems, while you are at it, you can get a more efficient controller that changes the RPMs of the compressor.

If you download the PDF from SECOP, the manufacturer of the fridge components, there is a lot of interesting info of what can be tweaked to make the unit more efficient

Mike Hanyi

its the same components

Coastal climate sells one-
https://www.coastalclimatecontrol.com/index.php/re...y=25823702

and Isotemp has had this for years

https://www.indelwebastomarine.com/int/products/cooling-technology/isotherm-smart-energy-control/

Thu Apr 23, 2020 3:23 pm

Thank you Mike. I'll do some research. :D

Thu Apr 23, 2020 4:07 pm

Hi Dave:

I got the Inkbird STC 1000 for my Truckfridge. The install was easy and that $20 thermostat has worked perfectly. The same unit is made by many manufacturers under different manufacturer names, but usually called "STC-1000" . The key thing is to get the 12V unit, not the 120 volt unit that home brewers use. The faceplate is 1" high and 3" wide, much smaller than the online pics suggest. I installed it in the Westfalia cabinet face on the far left. (Pics will follow.)

The factory Truckfridge uses a snap switch type of thermostatic switch. Find the wires connected to that switch, add some length and connect them to the Inkbird unit. You will need to drill one hole in the TF cabinet to allow the thermistor to be installed. The STC-1000 has a lot of online support, which is good because the instructions are written in impenetrable "Chinglish". The online community has provided usable translations.

Here's a link to the Inkbird STC-100 thermostat:

https://www.amazon.ca/gp/product/B073FDF6VJ/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1

Mon May 04, 2020 2:55 pm

I found a wireless one on amazon sensor is inside fridge and I have guage on the dash gives me temp in van and fridge temp about a year still doing fine. I think it was 12 bucks

Mon May 04, 2020 2:58 pm

West Marine had these on clearance last month for $89, but I think they are sold out. I just put the Isotherm in my TF49.

https://www.westmarine.com/buy/isotherm--isotherm-smart-energy-controller-dc-only--14015747

kourt

Mon May 04, 2020 3:09 pm

Commercial food service has these for walk in units and stand alone units.

A myriad of options and prices.

Dave

Sat Nov 28, 2020 4:22 pm

I would like to do this thermostat modification to my TF65. Has anyone tried to route the temperature probe under or through the door seal instead of drilling a hole through the back?

Sat Nov 28, 2020 5:16 pm

letsrig wrote: I would like to do this thermostat modification to my TF65. Has anyone tried to route the temperature probe under or through the door seal instead of drilling a hole through the back?
No, because that would have several disadvantages, the main one being that it'd be almost impossible to seal properly around the wire, so allowing heat in/coolth out. It'd be pretty tricky to tidy the wire away at the side as well.

Drilling a hole in the back is no big deal - easily sealed with some caulk.

Sat Nov 28, 2020 5:31 pm

Today I picked up a pair of these for $8 US from Amazon
https://www.amazon.com/gp/aw/d/B07CH7W3XP?ref=ppx_pt2_mob_b_prod_image

Going to do a similar mod to my cheap 12v Peltier fridge.

One thing to keep in mind - the voltage regulator on this is a bit cheap and won't like 14v coming from a charge system. So you'll want to use a regulator circuit such as a 1N5349 Zener diode and series resistor to limit the voltage to 12V
(lots of how tos on Google for this)
https://envistiamall.zendesk.com/hc/en-us/articles...structions

Cheers,
Matthew

Sun Nov 29, 2020 5:32 am

the small controller from Amazon is very interesting,
DC fridges work better on 12.5 and above, I have read that when using on
LI-ON , and battery is at 11v the fridge does not work properly,

I think a solution is a voltage stabilizer set at say 13v, and then adding a thermostat.

Sun Nov 29, 2020 4:23 pm

For anyone else who wants to add the inkbird ITC-1000F 12v as their temperature controller, I thought I would post my wiring configuration to ensure myself and future users are connecting it properly. Please refer to the accompanying photos and compressor connection descriptions for reference and let me know what I've got all wrong!

Wiring for Inkbird ITC-1000F on a Truck Fridge TF65 AC/DC

Refer to pictures for number/letter references.

Inkbird power - via the fridges light source (12v even when connected to AC)
negative wire - Inkbird 1 spliced into Secop 'C' (of AC combo)
POsitive wire - Inkbird 2 spliced into Secop 'A' (of AC combo)

Inkird Temp sensor -
inkbird 3 and 4

Inkbird Cooling -
inkbird 7 connected to Secop 'C'
inkbird 8 connected to Secop 'T'
Secop C connected to Secop P (original stock configuration)

The compressor control units have the following connections:

-, + Main supply voltage. Nominal voltage 12 V DC and 24 V DC, range: 9.0 to 32 V DC.

+, F Fan connection, max. 5 W, connect always 12 V fan (even in 24 V systems).

D/I: Connect either an Error LED between + and D/I for a simple error indication.

P, C Connect a battery protection resistor to select the required battery cut out value.

C+T Connect either a mechanical thermostat, a mechanical thermostat in series with a speed programming resistor or a NTC temperature sensor.

L, N Main supply voltage, voltage range 100-240 V AC 50/60 Hz

A, C Lamp connection (max. 5 W, connect always 12 V)

Mon Nov 30, 2020 10:30 am

I think you have wired the TF49 and the inkbird correctly. I followed up on all the schematics for Danfoss wiring. How does this work so far? How and where did you install the digital thermostat? Also where did you drill the hole for the thermistor pass through and what mounting location? Any pictures? How does the Inkbird hold up bouncing down the highway? I have had the internal thermostat cut out on occasion. (another reason to replace)

Mon Nov 30, 2020 10:52 am

puchfinnland wrote: and Isotemp has had this for years

https://www.indelwebastomarine.com/int/products/cooling-technology/isotherm-smart-energy-control/

CAUTION - this unit does not work if you are using lithium batteries. The Isotherm Smart Energy Control saves energy by lowering the fridge temp when it senses alternator charging by the change in voltage. This stores some extra cold in the food in the fridge. Problem is the LIFEPO4 batteries rest at a charge above the threshold where the Isotherm thinks AC charging is happening so it always thinks you are charging.

Mon Nov 30, 2020 12:45 pm

John Sullivan wrote: I think you have wired the TF49 and the inkbird correctly. I followed up on all the schematics for Danfoss wiring. How does this work so far? How and where did you install the digital thermostat? Also where did you drill the hole for the thermistor pass through and what mounting location? Any pictures? How does the Inkbird hold up bouncing down the highway? I have had the internal thermostat cut out on occasion. (another reason to replace)

My TF65 is sitting in my living room at the moment. LOL. I have not started the installation yet, just planning. I wanted to make sure my wiring plan looked legit before attempting. As for the thermistor, i was thinking of running it through the fridge door seal in the top hinge side corner instead of drilling a hole in the back. I would use an awl to make a very small hole in the accordion part of the fridge door seal and run the wire through that. Also, on each side of the incision/entry point I would anchor the wire (not sure how yet) so that there is no chance of any stress on the entry point. Inside the fridge, the wire would route beside the original thermostat and use the current stock wire clamp on the ceiling and finally rest on top of the freezer. If this didn't work out, i think the small hole in the fridge door seal would seal quite easily when the seal compresses with the door shut. This is an idea i will explore more when my installation starts.... sometime in the near future.

Mon Nov 30, 2020 7:32 pm

I have been considering this...

http://coastalclimatecontrol.com/images/PDF/Refer/Merlin-II-Instructions-v3.pdf

Tue Dec 01, 2020 12:23 am

I used a $16 INKBIRD temp controller. They are allover the web, also branded "BAYITE" and other names.
You can abrade the funny name off by scratching a razor blade edge across the paint until its gone.

I cut it into the Westfalia faceplate over on the left.
I wish I could have cut it into the Truckfridge door.

There are other smaller temp controllers online that could go in the Truckfridge door panel.

The Truckfridge repair facility in Bellingham, WA (SeaFreeze) made this image for me. I paid him $30 for to make me this diagram.
He wrote (pencil, connect to C & T) but I added the truckfridge image & green lines.

The guy said something like:

"you may run into trouble getting it to work as you want. You will notice that Truckfridge clips their temperature probe to the freezer condenser element, it's not out in the open air of the fridge. So they are using a much colder location to control the compressor where the numbers you might see on the readout is below freezing. You will probably want to see a number like "34°" on the display. 34 is a "nice number" but it may not control the compressor very well. We could probably get it setup for you with controllers that we have, but you might have a bit of learning ahead to get what you want."

I think they said they would have done it for a fairly nominal amount, like $70 but I was all confident in my $16 unit and that just hanging my temperature sensor in the center of the fridge should do it.

I drilled a (vertical) hole in the back, near the compressor mounting, and the sensor hangs down in the centroid of the fridge.

The number on my display are un-aesthetic. There will be items with frost on them inside, while the display ranges between 38°F and 45°F which is not an appetizing number. A thermometer inside the fridge confirms it's OK (32°-36°) but where do you put the temp guage? It migrates around inside as the wife gets in and out of it.
She just says "It would be nice if it worked" meaning: "I wish the number was 34°F".

Note the INKBIRD readout can be stepped up or down, very simply, easily.
I can step it down 6° so it then reads from 32° - 39°.

Perhaps it can be made to work, but I need to put more effort into it.
Basically the thermomenter inside said temp is +OK so I've gone to the current program of just ignoring the digital number.

However...... it does seem to run the compressor less often on the INKBIRD, which may help with battery usage.

Tue Dec 01, 2020 10:46 am

I've just ordered my Inkbird as well, to replace the Isotherm smart thermostat I installed last year. DeLvxe is correct--that Isotherm thermostat relies on voltages of batteries that are assumed to be lead acid. My house batteries are LiFePO4. This summer my fridge ran fast through the entire three week road trip, confirming the LiFePO4 higher voltage/always-looks-like-it's-charging theory.

I'll document my install and see how it goes. More later.

kourt

Thu Dec 03, 2020 11:01 am

Update: I have changed my mind.

While the Isotherm smart thermostat I have installed does run fast constantly in smart mode due to my LiFePO4 batteries, it runs just like the original TruckFridge thermostat when I switch it off of smart mode. So essentially I currently have the best of both worlds--a thermostat that performs either way based on what I mode I select.

The Inkbird is a binary thermostat controller with a nice feedback display. It is not sophisticated enough to vary the compressor speed of a TruckFridge. You set a temperature range, and it turns the compressor on/off. Yes, it has a neat display and buttons. But to mount it properly, you have to locate that display apart from the refrigerator, which means any time I remove the refrigerator (which happens about three times per year) I have to deal with the more complex installation. All that for a thermostat that doesn't really add any value apart from its temperature display--which I get with the analog thermometer I keep in my refrigerator.

The Isotherm that I use now can be selectively switched to run binary based on temperature probe feedback, based on a gradient of six different temperature ranges, or it can be switched to run the compressor at high speed and against voltage and temperature feedback, and then dial back power consumption of fans or the compressor based on available voltage. All mounted on the refrigerator. Manual for the Isotherm.

I'll keep the Isotherm installed and keep the Inkbird in its original box for now. It might be useful eventually, but for now, I can't see how it will improve the refrigerator over my Isotherm smart thermostat.

kourt

Thu Dec 03, 2020 2:08 pm

kourt wrote:

While the Isotherm smart thermostat I have installed does run fast constantly in smart mode due to my LiFePO4 batteries, it runs just like the original TruckFridge thermostat when I switch it off of smart mode. So essentially I currently have the best of both worlds--a thermostat that performs either way based on what I mode I select.

kourt

Unless I am missing something, I don't think there is any benefit to the isotherm smart controller if you are running LIFEPO4. The "auto" mode doesn't work with these batteries and I think turning it on while driving only turns down the temp slightly in the fridge. You can do manually with the original TF thermostat. There may be some benefit to the soft start, but I haven't really noticed a difference.

Isotherm does offer smart thermostat which is supposed to be compatible with LIFEPO4 batteries. They really went outside the box and named it the "Intelligent" controller.