New fridge efficiency!

[heritage]

Very cool indeed, Jackdaw. Could you please tell me where you installed it and how is it ventilated? Where does the hot exhaust air exit?
Many thanks.
Jess
(Hunter 27, Jacksonville, FL)

I installed an Isotherm ice box conversion unit in my H27 this spring. Here is where I installed the compressor: It is located below the two drawers that are below the sink in the galley. I cut out a spot to install a grill to improve air circulation. In this pic you can see where the freon lines go into the ice box:

 

[Benny17441]

I don't have a dog in this race, just suggesting you get a better testing tool. Nice refrigerator if it can run 12 hours and only used 8.5 ah.

 

[Jackdaw]

I don't have a dog in this race, just suggesting you get a better testing tool. Nice refrigerator if it can run 12 hours and only used 8.5 ah.

Welcome to the brave new world of small smart fridges. Here are the published specs

Isotherm GE 80S Compact Air Cooled Refrigeration Component System with ISEC

• Max Draw: 2.5 Amp
• Hourly Draw: .3 Amp (Based on System Reaching Economy Mode)
• Hourly Draw: .8 Amp (Based on Average Economy Mode / Regulated Mode)

Ambient air temp, door openings, insulation, and content of the box will effect cycle% and the DC draws, but as you can see the numbers I got were not unexpected, and also match number others are seeing with GE80 ISEC installs on well insulated boxes of that size.

PS - The ISEC controller is available as an add-on for most Danfoss compressor-based systems.

 

[redhead78]

Jack, I also installed a small isotherm 3201 ASU, small plate, I really was impressed with the ASU," automatic start up". I installed 1 layer of 1/2" foil coated blue strofoam glued on all side walls followed by a 1/2" layer of Azek sheet, glued over it, for better efficiency. Then installed the holding plate. I like the fact it has a miser setting it runs on, then when it detects 13.5 or more volts it runs flat out and freezes the plate. its my first year with this and I'm at a mooring with 2- 100 watt solar panels and this weekend it kept a steady 42 degrees in the box. I am not going to leave it on all the time but I go to boat most times Friday to Monday, I throw 2 home frozen blocks in and let it go all the long weekend. I should have done this long ago. Red

 

[Jackdaw]

Jack, I also installed a small isotherm 3201 ASU, small plate, I really was impressed with the ASU," automatic start up". I installed 1 layer of 1/2" foil coated blue strofoam glued on all side walls followed by a 1/2" layer of Azek sheet, glued over it, for better efficiency. Then installed the holding plate. I like the fact it has a miser setting it runs on, then when it detects 13.5 or more volts it runs flat out and freezes the plate. its my first year with this and I'm at a mooring with 2- 100 watt solar panels and this weekend it kept a steady 42 degrees in the box. I am not going to leave it on all the time but I go to boat most times Friday to Monday, I throw 2 home frozen blocks in and let it go all the long weekend. I should have done this long ago. Red

Exactly. Like your unit, the ISEC is designed to use the liquids in your box as a cold plate. When it detects aux power (+13V) it revs the the compressor and drives the contents of the box close to freezing. Once you are back on battery, it cycles on a very low compressor setting (something the standard units cannot do) until the box comes back to the original setting (say 42F), then it uses the settings and readings to modulate the compressor to minimize power consumption to the tune of 30-50% savings.

As you note, this is not insignificant. I could leave BlueJ on a mooring with the fridge on, kept charged by a small solar panel.

 

[jviss]

When trying to ascertain state of charge by terminal voltage, which is dubious at best, it's important to draw off any surface charge first, but putting a load on it temporarily.

 

[jviss]

The insulation in the C36 icebox is said to be inadequate by modern standards. I have never seen it, but the lids' insulation is quite thick.

The spec for the Tartan 3800 says the icebox insulation is 4" foam (10cm). So I guess it should be fairly efficient! I'm looking forward to it, and intrigued by the ISEC control.

 

[Chief RA]

Just for info , I use an Isotherm 2.8cf reefer in my Catalina 250 and with 160 watt solar. This unit only draws .7 amps per hour and is a great unit. Chief

 

[jviss]

Just for info , I use an Isotherm 2.8cf reefer in my Catalina 250 and with 160 watt solar. This unit only draws .7 amps per hour and is a great unit. Chief

Do you mean that over a day, it draws, on average, 0.7A per hour? As, for example, a 25% duty cycle where when it's running it draws 2.8A?

 

[Chief RA]

Yes Chief

 

[Justin_NSA]

This may be my next off season mod. My system is dead. Rather than resurrect an almost 25 year old system, I'm going to replace it. For now I'm spending $$ on dry ice to keep the box cold thru the weekends.

 

[Chief RA]

Justin: Mine cost about $700 and bought it online. Chief

 

[Justin_NSA]

Thanks Chief. I saw it at Defender for $845, but I'm definitely going to shop around for a deal around Christmas time.

 

[NotCook]

Is anyone able to compare these to the SeaFrost units? We've been contemplating installing their units for both fridge and freezer.

 

[dLj]

Is anyone able to compare these to the SeaFrost units? We've been contemplating installing their units for both fridge and freezer.

Indeed, I would love to hear about this also.

dj

 

[Chief RA]

I can only tell you that I have had my reefer 4 years and it works great! Chief

 

[Hayden Watson]

This may be my next off season mod. My system is dead. Rather than resurrect an almost 25 year old system, I'm going to replace it. For now I'm spending $$ on dry ice to keep the box cold thru the weekends.

On most of these systems, you buy the compressor and evaporator separately. If you have a non-functional system you can replace the half that is the problem. On my 2004 AB Cold Machine I had a failed evaporator. My sister went sailing with me for one day-sail and spilled a diet Coke in the icebox. She didn't' tell me and did a half-a$$ job of cleaning it up. The acid in the Coke ate a hole through the evaporator. replaced it and recharged. It was worked great ever since.

 

[walt]

But the biggest news is the efficiency. The boat has a single Group 29 battery rated at 85 amp/hour capacity. Yesterday as a test I unplugged the boat from shore power at 7AM. It was in the 80s to 90 all day. Fridge is set at 42F. Twelve hours later I came back and checked the resting battery voltage.


That's 90% of full charge, meaning that the fridge used 8.5 amps in those 12 hours, or a 0.7A/hour run rate. Very good, and matches specs and other users observations. That's less than an incandescent anchor light!

Ive been looking at these Isotherm threads and want to point out something about this data point. Assume that the resting battery voltage before and after is "accurate enough" and that 8.5 amp hours was used in 12 hours.

What you have to keep in mind is that during the 12 hours of this test, there were no charging sources on the battery, only drains. This is exactly where the ISEC controller would somewhat shut things down and use only a minimum amount of power. In this case, it would be relying on some thermal stored cold that was created when the boat was in the slip and plugged into AC and something charging the battery.

I think its very likely that as soon as you got back to the slip and plugged back into AC, the ISEC controller kicked into peak current for some period of time and during this time, you likely used considerably more than the .7 A/hour rate.

I dont think we can use this example to try and figure what one of the fridges would use on a daily basis. Ie, I dont think we could double the 12 hour usage to estimate what would happen on average for 24 hours. Doubling 8.5 amp hours would be 17 amp hours but there is a very good chance this number is too low for average 24 hour usage. This really needs a charge monitor on the battery checked after 24 hours.

FYI, this experiment is useful for the way Jackdraw uses the fridge. I was looking for average 24 hour usage and at first assumed I could just double the number but I dont think you can.