Adding a new DC Fridge during a LA Heatwave

[GeorgeRa]

Originally Posted by themexicandoctor

George,

Thank you!

You know I looked at the Isotherm ITEC & ISEC Systems as an add on when I was deciding between the Novakool, Vitrifrigo or Isotherm 85 or Isotherm Cruise 100.

I reaeatched everything about them & how people with the ASU's had issues sometimes, etc, especially on boats & in Sportsmobile Vans.

I won't pretend to understand the intricacies of how it works but I do know when more current is available it essentially stores more cold energy into the unit.

But I never thought to see if it would work with the Novakool system?

Will send an email to them tonight.

I didn’t mentioned ASU, a 30 years old Isotherm technology.

I have and like SEC, Smart Energy Controller. It is an electronic thermostat with some smarts replacing electromechanical capillary on/off thermostat EMT, so I like SEC better than EMT and don’t know much about ASU, the power of our love affair with acronyms.

Seriously,

Smart energy controller:
1. It is an electronic thermostat
2. It measures temperature of the refrigerator, not cold plate
3. It can vary compressor speed based on cooling demand
4. It automatically adjusts refrigerator (not cold plate) temperature set point down, but above freezing, in presence of excess energy
5. It is using refrigerator content as a cooling buffer
I assume your fridge is using capillary thermostat not an electronic one.

[GeorgeRa]

Originally Posted by tgregg

George / TMD,

Isotherm has a newer unit that works with either a DC only or an AC / DC Danfoss controller called the 'Isotherm Intelligent Temperature Control'.

It adjust compressor speed, provides fast cool and overcool to provide 30 - 50 % energy savings and it's more user friendly than the ISEC unit. It doesn't use dip switches and has an external display for programming, setting the temperature and displaying the refrigerator. temperature.

it works with any refrigerator that uses the Danfoss / SECOP compressor and the appropriate Danfoss controller.

I didn't know, thank you. I am going to put this on my list to evaluate, it would be nice to have temperature display. I am glad they moved away from ancient DIP switches.

https://www.indelwebastomarine.com/u...r%20Fahrenheit.

[booster]

Personally, I like the ITC version of the smart electronics from Isotherm, as it would do what we want, is more user friendly, and displays temps.


Unfortunately, our unit is too old for it to be retrofit as the control board isn't compatible. It is about 10 years old. If we have to get a new control board, I think a complete new frig may as well be done, and sell the old one.

[GeorgeRa]

Big difference between ITC and SEC could be in ECO/overcooling function. It seems as in ITC ECO is manual, not automatic like with SEC where it is set by DIP switches. I like temperature display and simpler programming but lack of automatic overcooling would be a no no for me.

https://forums.sailboatowners.com/th...ontrol.197505/

[tgregg]

Originally Posted by booster

Personally, I like the ITC version of the smart electronics from Isotherm, as it would do what we want, is more user friendly, and displays temps.


Unfortunately, our unit is too old for it to be retrofit as the control board isn't compatible. It is about 10 years old. If we have to get a new control board, I think a complete new frig may as well be done, and sell the old one.

I had to buy a new controller too, but it was a simple job involving just 1 screw.

[tgregg]

Originally Posted by GeorgeRa

Big difference between ITC and SEC could be in ECO/overcooling function. It seems as in ITC ECO is manual, not automatic like with SEC where it is set by DIP switches. I like temperature display and simpler programming but lack of automatic overcooling would be a no no for me.

https://forums.sailboatowners.com/th...ontrol.197505/

George,

i saw that thread too, but i don't think they knew what they were talking about. One poster was talking dip switches and there aren't any dip switches.

you can choose not to use over cooling if you want, but if you choose it, it works based on battery voltage. It over cools when the batteries are being charged and stops when they aren't.

European mfgs often have superior and innovative technology, but translating manuals into English is not a strong suit.

[booster]

Originally Posted by GeorgeRa

Big difference between ITC and SEC could be in ECO/overcooling function. It seems as in ITC ECO is manual, not automatic like with SEC where it is set by DIP switches. I like temperature display and simpler programming but lack of automatic overcooling would be a no no for me.

https://forums.sailboatowners.com/th...ontrol.197505/

Wow is that forum hard to follow, almost everybody appeared to be talking about the SEC instead of the ITC with a couple of exceptions.


Lots of talk about the manual being less than accurate, which it may be as it is confusing.


It appears that there only two settings, ECO and ITC.


ECO appears to pick the most efficient compressor speed from power use only, with no relation to cooling capacity, so how the compressor is sized to the box is critical for that. In our case, it might be fine 98% of the time as ours will stay cool on lowest compressor speed up to 100*.


There is also a setting deeper in the menus for "permanent overcooling" but doesn't really tie it in to how that fits in to the cycles.


ITC is the normal mode, it appears, and looks to run at some predetermined speed that is not stated. It would run at that speed until the input voltage went above the setting for battery protection (battery protection includes 3 temps, cutoff, restart, and going to overcool). Medium setting would start overcool at 12.9v so would indicate being on charge for most of us. It also states that this happens only if overcool is turned on, but isn't clear if that means the "permanent overcooling" turned on or not.


So, the way I would read the instructions would be that in ITC mode it would run as some speed that is built in to maintain the temp set. It is probably a mid range speed so it always would have enough capacity for any conditions. It would go into overcool mode if it sees voltage above the setting in battery protection setting for overcooling but only if the permanent overcooling is enabled.


It doesn't claim that the unit will continuously vary the compressor speed to match the cooling needed to keep the box on temp, which would be a nice feature which I think the SEC probably does.


In reality, for us we really don't need the overcooling as we have so much battery and charging capacity as the savings in power would be quite small by comparison, and if it actually is running at very low speed in ECO like it probably would, we would be able to just stay right in ECO all the time as that is about what we do now.


Very interesting information and would definitely give me pause as the what we would do if we need a new frig. I really don't like the failure rate we have had with mechanical thermostats either.

[themexicandoctor]

Originally Posted by GeorgeRa

I didn’t mentioned ASU, a 30 years old Isotherm technology.

I have and like SEC, Smart Energy Controller. It is an electronic thermostat with some smarts replacing electromechanical capillary on/off thermostat EMT, so I like SEC better than EMT and don’t know much about ASU, the power of our .

George,

I mentioned the ASU which I believe stands for AUTOMATIC START UP because a couple of Sportsmobile owners & a few boat owners were having issues with one or the other interfering with the operation of the ISEC or ITEC.

I did ask the Head Engineer & will follow up with his answers in the next post.

[themexicandoctor]

Spoke to Marian, the Head Engineer & this was the gist of our conversation compiled in an email to him;

1. I could block off that huge air volume at the lower air vent (I hear your point but I do remember the emphasis on having 30sq inches of ventilation down there &*then how would cool air enter the fan area?)


2. Add some Thermistors or (?) Resistors to the unit, no more the 1500 ohms


3. Or add a Potentiometer to the front of the fridge.


4. Or go ahead with adding the Isotherm ISEC or ITEC but there is a potential for it to fail & complicate the Bulletproof Simplicity of the Novakool technology


5. Carefully orient the fan position by bending it gently so that it draws hot air up & away.


I do*agree with points 2-4, I don't want to complicate this.

========================

He is going to get back to me.

In the meantime I am going to add a Sensorpush back there to check the temperature.

===============

New question described in post #14; next week I am doing away with the old battery locations & putting in 2 new 225ah 6 volt Lifeline Batteries.

What is more efficient;

Having the new batteries mounted as close to the battery shunt & the solar cables?

OR, is up to 4 feet away not going to make a sizable difference (this will save me having to move the Inverter).

Or is it better to move the inverter?

[GeorgeRa]

Originally Posted by themexicandoctor

Spoke to Marian, the Head Engineer & this was the gist of our conversation compiled in an email to him;
1. I could block off that huge air volume at the lower air vent (I hear your point but I do remember the emphasis on having 30sq inches of ventilation down there &*then how would cool air enter the fan area?)
2. Add some Thermistors or (?) Resistors to the unit, no more the 1500 ohms
3. Or add a Potentiometer to the front of the fridge.
4. Or go ahead with adding the Isotherm ISEC or ITEC but there is a potential for it to fail & complicate the Bulletproof Simplicity of the Novakool technology
5. Carefully orient the fan position by bending it gently so that it draws hot air up & away.
I do*agree with points 2-4, I don't want to complicate this.
…………

Sorry Dr, I am not getting it. Who is the head engineer, from Novakool or from Indel? Adding resistors to what, Danfoss control, is this in installation manual?

4. Or go ahead with adding the Isotherm ISEC or ITEC but there is a potential for it to fail & complicate the Bulletproof Simplicity of the Novakool technology

I know what SEC or ISEC is, no clue about ITEC, more complicated than bulletproof Novakool, sounds like someone from Novakool.

[themexicandoctor]

Originally Posted by GeorgeRa

Sorry Dr, I am not getting it. Who is the head engineer, from Novakool or from Indel? Adding resistors to what, Danfoss control, is this in installation manual?

4. Or go ahead with adding the Isotherm ISEC or ITEC but there is a potential for it to fail & complicate the Bulletproof Simplicity of the Novakool technology

I know what SEC or ISEC is, no clue about ITEC, more complicated than bulletproof Novakool, sounds like someone from Novakool.

The Head Engineer at Novakool is the one who suggested the possibility of the;

1. Potentiometer

2. The Thermistors/Resistors

3. That they, Novakool, did have one owner who added the ISEC/ITEC but then ran into problems.

4. Blocking off the lower vents

5. Carefuly bending the existing R3800 Fan upwards so as act as an extractor fan. One of the Giants here, also mentioned this.

PS. There are two systems available from Isotherm for their units, the ITEC & the ISEC.

[booster]

Originally Posted by GeorgeRa

Sorry Dr, I am not getting it. Who is the head engineer, from Novakool or from Indel? Adding resistors to what, Danfoss control, is this in installation manual?

4. Or go ahead with adding the Isotherm ISEC or ITEC but there is a potential for it to fail & complicate the Bulletproof Simplicity of the Novakool technology

I know what SEC or ISEC is, no clue about ITEC, more complicated than bulletproof Novakool, sounds like someone from Novakool.

The resistance in the thermostat circuit sets the compressor speed, at least on the mechanical thermostats. If you put in a switchable resistance or variable, you can control the compressor speed manually. I have a rotary switch to select speeds.

[themexicandoctor]

I started simply.

The fan is now horizontal.

Let's see what happens with the performance.

[themexicandoctor]

I wonder what will happen to the module heat, probably a 30% reduction in direct cooling of that module block.

[themexicandoctor]

I drove to the Installer & we bend the fan up to a horizontal position.

As you see the Temperature Data start to take an upward to tick, this was the same time - very frustrating.

The Fridge is now ay setting #5 of the range from 1-7.

And its not getting any cooler weather on the horizon.

[themexicandoctor]

Here it is.

[GeorgeRa]

Just checking, did you flip the fan so it is blowing upwards?

[themexicandoctor]

Originally Posted by GeorgeRa

Just checking, did you flip the fan so it is blowing upwards?

Yes Sir,

The last 4 posts talk about this - IT GOT WORSE!

Since then I bent it down to a 30% angle versus the factory 45% angle.

My unit is now at #5 on a 1-7 dial.

It cannot keep up, I wonder if i turned it to #6 during the day if that would increase the compressor speed?

The Engineer at Novakool said I could try the Isotherm add on but the last person who did it with a Novakool did NOT have a successful experience.

Now in just a few hours, had to run the Generator for 3 hours to even get to 100% full, in the 4 hours since I am 20ahs used up with the fridge, lights & fans & it does not look good.

Can these units run non-stop without failure?

[GeorgeRa]

If this is the thermostat https://www.suremarineservice.com/Ga...SABEgIMxfD_BwE it is a capillary thermo switch, purely mechanical on / off. The number indicates temperature setpoint, very doubtful that it can vary Danfoss compressor speed.

I think Avanti mentioned it a couple times, what is the temperature in the back of the fridge?

[themexicandoctor]

Originally Posted by GeorgeRa

If this is the thermostat https://www.suremarineservice.com/Ga...SABEgIMxfD_BwE it is a capillary thermo switch, purely mechanical on / off. The number indicates temperature setpoint, very doubtful that it can vary Danfoss compressor speed.

I think Avanti mentioned it a couple times, what is the temperature in the back of the fridge?

Yes that's the one.

I just drive 30 minutes & have beeb parked for 45 minute.

At around 10pm, it sat at 40 degrees & wouldn't go down.

Before I started driving I turn the knob back to #4 & you can see the temp is 28.3°