Isotherm Cruise 85 caput.

[booster]

Originally Posted by GeorgeRa

I am leaning towards ICT, primarily due to easier interface, AKO menu needs manual. Sensor would be located on the back wall where my current SEC sensor is, it is possible SEC and ICT used the same sensor, I need to measure it.

My experiment with $10 generic capillary sensor was a fiasco, I couldn’t dial a working temperature.

I will use ICT for turning fridge on/off and have additional switch for the internal lamp mounted on the lamp housing.

Most of the capillaries have a range adjustment screw that is accessible through the case. They are tiny to say the least. I had to adjust the stock one in our new Isotherm or it wouldn't go low enough, especially with the tray out. You the major range with the screw and fine tune with knob in the frig. You can use the same thermostat for frig or freezer applications so they have a lot of range.

[GeorgeRa]

Originally Posted by booster

Most of the capillaries have a range adjustment screw that is accessible through the case. They are tiny to say the least. I had to adjust the stock one in our new Isotherm or it wouldn't go low enough, especially with the tray out. You the major range with the screw and fine tune with knob in the frig. You can use the same thermostat for frig or freezer applications so they have a lot of range.

Thank you, yes, I found the little adjusting screw. I already marked the front galley panel for cutting so ITC is going in.

[GeorgeRa]

I finished comparing ECO to ICT modes of operating. Largest variable was likely ambient temperature. In conclusion ECO savings are about 15% over ICT energy consumption.

At charging voltage available ITC’s overcooling mode could be beneficial, but without charging ECO is definitely better.

There was significant reduction of compressor noise on ECO versus ICT.

I also noticed a very clean in the fridge temperature curve, not an erratic one like with prior SECOP/SEC

My previous measurments with AKO were likely very low due to low ambient temperature, at night could have been closer to 50F.

[booster]

Originally Posted by GeorgeRa

I finished comparing ECO to ICT modes of operating. Largest variable was likely ambient temperature. In conclusion ECO savings are about 15% over ICT energy consumption.

At charging voltage available ITC’s overcooling mode could be beneficial, but without charging ECO is definitely better.

There was significant reduction of compressor noise on ECO versus ICT.

I also noticed a very clean in the fridge temperature curve, not an erratic one like with prior SECOP/SEC

My previous measurments with AKO were likely very low due to low ambient temperature, at night could have been closer to 50F.

Interesting that you are seeing a much lower hysteresis than I did. Were your temps measured with the a fact responding temp sensor or one that is damped a bit? I assume it was on the chart recorder you showed earlier.


It would have been interesting to see what the ITC temp readout was reading at those points as I was always a bit suspicious that the readout was not all that accurate on ours. With it's degree Centigrade resolution and two degree Fahrenheit poorly done conversion I am not surprised though. Our readings were done with the indoor/outdoor wireless thermometer we use normally in a ziplock bag so somwhat damped for sure, but that would usually reduce the seen spread so kind of odd. Fast reacting usually gives a wider range. Having the recorder would be nice.


Drip tray in or out? That can make quite a bit of difference in all the reading and smoothness of swings, I think, especially when sensing in the frig.


Any thermal ballast in the frig? That would probably change the "flatness" of the curve based on how much you have.


I have to wonder if the new design of the freezer box we have is making a big difference in hysteresis. I never understood why the changed that as the design seemed to violate the basic premise of using the freezer box as the evaporator heat exchanger. I have contemplated trying to get the plastic shroud off the box many, many times and still may try to do it. Access is very hard to do much in there. Bummer is that it also might affect the freezer door support and sealing.


Our old Cruise 85 was like yours is and the box was uncovered completely and the door didn't close tightly at all so lots of cold air transfer to the box which seemed to work a lot better in many ways, albeit with warmer and uneven front to rear freezer temps. I think an uncovered freezer box with a tighter sealing door to make the freezer temps more uniform inside it would be the best setup.


Very odd indeed that you are getting about 1/2 of the hysteresis that we did in all ICT modes. It may just be that the freezer box changes make the ICT work better on yours. The one size fits all for all kind of differently designed and sized frigs probably isn't the best move for them.


You are are about the same running amps though at 2.88/2.68 in ECO mode, which is the 2500rpm and reducing you efficiency vs 2000. Too bad there isn't an way to change that. We consistently see about 2.1 amps with mechanical stat at 2000 rpm on the speed control and it definitely uses less power that way.

[GeorgeRa]

“Interesting that you are seeing a much lower hysteresis than I did. Were your temps measured with the a fact responding temp sensor or one that is damped a bit? I assume it was on the chart recorder you showed earlier”.

It is temperature variability measure by uncovered Sensorpush on the bottom of the fridge, center of the floor.

“It would have been interesting to see what the ITC temp readout was reading at those points as I was always a bit suspicious that the readout was not all that accurate on ours. With it's degree Centigrade resolution and two degree Fahrenheit poorly done conversion I am not surprised though. Our readings were done with the indoor/outdoor wireless thermometer we use normally in a ziplock bag so somwhat damped for sure, but that would usually reduce the seen spread so kind of odd. Fast reacting usually gives a wider range. Having the recorder would be nice.”

I didn’t record the readout on the ITC but usually was off by 1-to-2-degree F.

“Drip tray in or out? That can make quite a bit of difference in all the reading and smoothness of swings, I think, especially when sensing in the frig”.

Fridge was completely empty, no tray, no wire shelves, no box.

“Any thermal ballast in the frig? That would probably change the "flatness" of the curve based on how much you have.”

Empty, I agree.

“I have to wonder if the new design of the freezer box we have is making a big difference in hysteresis. I never understood why the changed that as the design seemed to violate the basic premise of using the freezer box as the evaporator heat exchanger. I have contemplated trying to get the plastic shroud off the box many, many times and still may try to do it. Access is very hard to do much in there. Bummer is that it also might affect the freezer door support and sealing.”

My tray has four half inch wide openings about 9-inch total length, so about 4.5 inch^2 opening, should be enough for the cold air flow.

“Our old Cruise 85 was like yours is and the box was uncovered completely and the door didn't close tightly at all so lots of cold air transfer to the box which seemed to work a lot better in many ways, albeit with warmer and uneven front to rear freezer temps. I think an uncovered freezer box with a tighter sealing door to make the freezer temps more uniform inside it would be the best setup.”

Cold air flow or sensor location will change system dynamics. For whatever reason Webasto folks added a stainless-steel tube for the temperature sensor increasing response time. I calculated duty cycle for ECO it was 40% and 32% for ICT.

“Very odd indeed that you are getting about 1/2 of the hysteresis that we did in all ICT modes. It may just be that the freezer box changes make the ICT work better on yours. The one size fits all for all kind of differently designed and sized frigs probably isn't the best move for them.”
“You are are about the same running amps though at 2.88/2.68 in ECO mode, which is the 2500rpm and reducing you efficiency vs 2000. Too bad there isn't an way to change that. We consistently see about 2.1 amps with mechanical stat at 2000 rpm on the speed control and it definitely uses less power that way.”

Less power indeed, how about higher duty cycle.

[booster]

Originally Posted by GeorgeRa

“Interesting that you are seeing a much lower hysteresis than I did. Were your temps measured with the a fact responding temp sensor or one that is damped a bit? I assume it was on the chart recorder you showed earlier”.

It is temperature variability measure by uncovered Sensorpush on the bottom of the fridge, center of the floor.

“It would have been interesting to see what the ITC temp readout was reading at those points as I was always a bit suspicious that the readout was not all that accurate on ours. With it's degree Centigrade resolution and two degree Fahrenheit poorly done conversion I am not surprised though. Our readings were done with the indoor/outdoor wireless thermometer we use normally in a ziplock bag so somwhat damped for sure, but that would usually reduce the seen spread so kind of odd. Fast reacting usually gives a wider range. Having the recorder would be nice.”

I didn’t record the readout on the ITC but usually was off by 1-to-2-degree F.

“Drip tray in or out? That can make quite a bit of difference in all the reading and smoothness of swings, I think, especially when sensing in the frig”.

Fridge was completely empty, no tray, no wire shelves, no box.

“Any thermal ballast in the frig? That would probably change the "flatness" of the curve based on how much you have.”

Empty, I agree.

“I have to wonder if the new design of the freezer box we have is making a big difference in hysteresis. I never understood why the changed that as the design seemed to violate the basic premise of using the freezer box as the evaporator heat exchanger. I have contemplated trying to get the plastic shroud off the box many, many times and still may try to do it. Access is very hard to do much in there. Bummer is that it also might affect the freezer door support and sealing.”

My tray has four half inch wide openings about 9-inch total length, so about 4.5 inch^2 opening, should be enough for the cold air flow.

“Our old Cruise 85 was like yours is and the box was uncovered completely and the door didn't close tightly at all so lots of cold air transfer to the box which seemed to work a lot better in many ways, albeit with warmer and uneven front to rear freezer temps. I think an uncovered freezer box with a tighter sealing door to make the freezer temps more uniform inside it would be the best setup.”

Cold air flow or sensor location will change system dynamics. For whatever reason Webasto folks added a stainless-steel tube for the temperature sensor increasing response time. I calculated duty cycle for ECO it was 40% and 32% for ICT.

“Very odd indeed that you are getting about 1/2 of the hysteresis that we did in all ICT modes. It may just be that the freezer box changes make the ICT work better on yours. The one size fits all for all kind of differently designed and sized frigs probably isn't the best move for them.”
“You are are about the same running amps though at 2.88/2.68 in ECO mode, which is the 2500rpm and reducing you efficiency vs 2000. Too bad there isn't an way to change that. We consistently see about 2.1 amps with mechanical stat at 2000 rpm on the speed control and it definitely uses less power that way.”

Less power indeed, how about higher duty cycle.

You have a slotted drip tray, but an open sided freezer box with no shroud around it? If so you are different than either of our Cruise 85s. The original had no slots in tray and it solid bottom with the only cold paths about 3/8" gap to the rear wall and a bit in the front between the frig door and the freezer door. Our later tray has a single slot and a few holes, so not much area. They also have a raised areas around each of the openings that would impede cold air flow through them. It also has the shroud around the freezer box. I think what you have would be the best solution of the three.


Certainly the duty cycle changes with compressor speed to longer runs fewer times per hour with a higher % run time. The lower compressor instantaneous power over a longer time is enough more efficient to have significant total energy use over a set period of time when compared to the higher speed with higher power. It was a significant increase in efficiency, maybe 15% IIRC. For me, duty cycle is only an issue when you run out of capacity to stay at temp and our old frig was able to keep up in the lowest compressor speed in 100-105* temps on the sunny side of the van in Zion. It was at, or very near 100% duty cycle but kept the temp steady through it all. We have not been beyond about 75* with the new one as the last hot trip was when the old on failed in 90+* temps in Custer.


I just thought to go back and look again at your results and am actually a bit surprised how high the are for a 68* ambient at 353 watt/hr per 24hr. I need to go back to my thread and look for sure but I think my final readings with tray out on the mechanical thermostat at 2000 rpm were a bit under 250wh/24hr with 70* ambient.


On edit: I went back to my old thread and looked. The 250whr/24hr was at 77* ambient, 38/40* frig, 20* freezer in lowest compressor speed.


The best reading was at 67* and 37/39* frig temp and it did the amazing to me 178whr/24hr.


You are closer to the Isotherm rating for the frig of 363whr/24hr with 77* ambient and 41* frig temp.

[GeorgeRa]

Here are the pictures of my fridge.

[GeorgeRa]

One more. Fridge was purchased from West Marine in 2013.

[booster]

Originally Posted by GeorgeRa

One more. Fridge was purchased from West Marine in 2013.

That is the same tray and freezer with the shroud around it that we currently have so your frig should perform similarly.


Did you see my edit above, it got delayed going in as I had to take care of something important.

[booster]

I just looked at my original test with the ITC and I also got 360wh/24hr on auto and 315whr/24hr in ECO.


I am still amazed at how much better the mechanical is for energy use with the speed control used. Of course, none of my testing didn't include anything with overcooling on with the ITC because we don't want to take the frig that cold.

[GeorgeRa]

Originally Posted by booster

I just looked at my original test with the ITC and I also got 360wh/24hr on auto and 315whr/24hr in ECO.


I am still amazed at how much better the mechanical is for energy use with the speed control used. Of course, none of my testing didn't include anything with overcooling on with the ITC because we don't want to take the frig that cold.

Indeed, it is amazing, I would think that high frequency compressor cycling with a sensor on the cool plate wouldn’t be very efficient.

Your ECO runs lower than mine, ITC is almost the same. It would be nice to have a small Wh meter just for fridge to find best setup in real life, but I couldn’t find one.

[booster]

Originally Posted by GeorgeRa

Indeed, it is amazing, I would think that high frequency compressor cycling with a sensor on the cool plate wouldn’t be very efficient.

Your ECO runs lower than mine, ITC is almost the same. It would be nice to have a small Wh meter just for fridge to find best setup in real life, but I couldn’t find one.

I use a Watt's Up accumulator meter but they don't seem to be available.

Here is a clone that looks identical and is much cheaper. Can't say how well it works.

https://www.ebay.com/itm/25546141155...UAAOSwvzliQzNH

Just connect these into a the power and ground to the frig and let it run and accumulate Wh, AH, max, min etc. I often left ours in even when driving.

[GeorgeRa]

So, I my ICT is in.

Original ICT display is very bright, to reduce the brightness I placed a small sheet of 50-80% gray filter in front of the display. The PCB and the bezel need to be separated and film must be cut to size of the window. https://www.amazon.com/dp/B09DY1ZHKS...roduct_details

If you use Mercury Grey Vycom HDPE here is some info about matching paint from Sherwin Williams. Paint is glossy, to change it to satin a satin clear overcoat can be used.

[booster]

Hi George, just reviving this to ask a quick question.


Did you ever measure the LED light voltage with the new controller?


Do you now have a 12v bulb in it?


I am experimenting with frig temp distribution and want to hook up a 2" fan to see if it would actually do any good for fully packed frig.

[mkguitar]

Originally Posted by booster

fully packed frig.

my internal fan was salvaged from an old vcr or satellite tuner, about 1 1/4" draws about 80 mA. makes a big diff for constant temps throughout the old 3 way. wiring enters fridge alongside the condensation tube

[GeorgeRa]

Originally Posted by booster

Hi George, just reviving this to ask a quick question.


Did you ever measure the LED light voltage with the new controller?


Do you now have a 12v bulb in it?


I am experimenting with frig temp distribution and want to hook up a 2" fan to see if it would actually do any good for fully packed frig.

Yes, it was 12V. I kept the LED bulb purchased from Isotherm folks which is 24V. It is not as bright as it would be on 24V.

[booster]

Originally Posted by GeorgeRa

Yes, it was 12V. I kept the LED bulb purchased from Isotherm folks which is 24V. It is not as bright as it would be on 24V.

Thanks George, that is what I thought/hoped it would be.