edit.. I put all the details of this project here (Jan 2019)
http://analogengineering.com/sail/mac/electric_fridge.html
I have an old 1990 Mac 26S that after seeing all the fridge stuff here, Im thinking about converting to solar powered ice chest. I know a few people here have done this and I am just thinking about this at the moment so I will just describe all the plans I have and welcome any feedback (I may not follow any advice but its certainly all welcome).
My ice box is custom with 2 inches of insulation in the walls and top loading hatch and 3 inches in the bottom. I think the volume that I would cool is right at 2 cubic feet (60 qt). This will be huge vol for us as in the past this had two gallons of frozen water in it plus a 10 pnd block of ice and we can get rid of all of that.
The cooler that Im thinking about has been talked about here and its the Isotherm GE80-SX with Isec. Part of the reason for picking this one is that the cold plat is 14" by 10" which I think I have room for. I sort of like the GE150 better but I dont think I have room for the larger evap plate (14" by 15").
I have two golf cart batteries on this boat and plan to power things completely with solar so Im of the impression that the Isec control will be as easy on the batteries as possible. Im used to having a huge reserve of capacity to daily usage and adding the e fridge greatly reduces my margin which makes me a little uncomfortable. But I believe the Isec control will work the fridge hard when the sun is shining and go easy on things when its not. My batteries will still likely get more of a workout than they have in the past..
I worry about the evaporator cold plate getting banged up in the food area.. Example, a six pack of beer smacking into it while sailing (water ballast boat can be like a big dingy in windy conditions).
I dont think I will need to worry about the heat generated by the compressor and trying to exhaust this from the boat. This setup uses a max of 2.5 amps and that is a max of a little over 30 watts and it should not run at that power all the time. It would seem that the heat from the compressor would be easy to manage and no problem to just vent the heat into the boat.
I know I can very comfy live on 30 watts of solar without the fridge. I am thinking 100 watts of solar will run the fridge fine. The panel size Im thinking of will be 140 watts. I would use a single panel about 60 inches by 26 inches (about 11 square feet.. YIKES) mounted above the boat stern. This size panel weighs about 26 pounds and if I keep all the mounting light weight.. I think I can live with this. FYI, a buddy gave me a bunch of carbon fiber cloth.. thinking about trying to do this with carbon fiber and epoxy plus some AL.. I somewhat worry about all that panel area back there as when the boat heals, that panel generates both lift and drag and the rudder has to work a little harder to balance that out which is both additional stress and drag.
Based on my past experience, 100 watts of solar will supply anywhere from 15 to 35 amp hours per day (MPPT controller) but I will assume that I might get 20 on average. The spec on the Isotherm say it only uses .3 amps average in economy mode (7 amp hours per day) but at the full 2.5 amp it can run at, that would be 60 amp hours per day. If I used a 24 volt panel, I could run 14 gauge wire for the long run to the controller. A 12 volt panel would require 10 gauge. I will have to buy a new controller regardless so have not decided on this yet.
I do not plan to have any sort of gas power generation over what my outboard provides. So I may have to put in a low voltage disconnect later and my backup would be if I ever had a time period of not enough sunlight, just shut the power off and buy some ice.
http://analogengineering.com/sail/mac/electric_fridge.html
I have an old 1990 Mac 26S that after seeing all the fridge stuff here, Im thinking about converting to solar powered ice chest. I know a few people here have done this and I am just thinking about this at the moment so I will just describe all the plans I have and welcome any feedback (I may not follow any advice but its certainly all welcome).
My ice box is custom with 2 inches of insulation in the walls and top loading hatch and 3 inches in the bottom. I think the volume that I would cool is right at 2 cubic feet (60 qt). This will be huge vol for us as in the past this had two gallons of frozen water in it plus a 10 pnd block of ice and we can get rid of all of that.
The cooler that Im thinking about has been talked about here and its the Isotherm GE80-SX with Isec. Part of the reason for picking this one is that the cold plat is 14" by 10" which I think I have room for. I sort of like the GE150 better but I dont think I have room for the larger evap plate (14" by 15").
I have two golf cart batteries on this boat and plan to power things completely with solar so Im of the impression that the Isec control will be as easy on the batteries as possible. Im used to having a huge reserve of capacity to daily usage and adding the e fridge greatly reduces my margin which makes me a little uncomfortable. But I believe the Isec control will work the fridge hard when the sun is shining and go easy on things when its not. My batteries will still likely get more of a workout than they have in the past..
I worry about the evaporator cold plate getting banged up in the food area.. Example, a six pack of beer smacking into it while sailing (water ballast boat can be like a big dingy in windy conditions).
I dont think I will need to worry about the heat generated by the compressor and trying to exhaust this from the boat. This setup uses a max of 2.5 amps and that is a max of a little over 30 watts and it should not run at that power all the time. It would seem that the heat from the compressor would be easy to manage and no problem to just vent the heat into the boat.
I know I can very comfy live on 30 watts of solar without the fridge. I am thinking 100 watts of solar will run the fridge fine. The panel size Im thinking of will be 140 watts. I would use a single panel about 60 inches by 26 inches (about 11 square feet.. YIKES) mounted above the boat stern. This size panel weighs about 26 pounds and if I keep all the mounting light weight.. I think I can live with this. FYI, a buddy gave me a bunch of carbon fiber cloth.. thinking about trying to do this with carbon fiber and epoxy plus some AL.. I somewhat worry about all that panel area back there as when the boat heals, that panel generates both lift and drag and the rudder has to work a little harder to balance that out which is both additional stress and drag.
Based on my past experience, 100 watts of solar will supply anywhere from 15 to 35 amp hours per day (MPPT controller) but I will assume that I might get 20 on average. The spec on the Isotherm say it only uses .3 amps average in economy mode (7 amp hours per day) but at the full 2.5 amp it can run at, that would be 60 amp hours per day. If I used a 24 volt panel, I could run 14 gauge wire for the long run to the controller. A 12 volt panel would require 10 gauge. I will have to buy a new controller regardless so have not decided on this yet.
I do not plan to have any sort of gas power generation over what my outboard provides. So I may have to put in a low voltage disconnect later and my backup would be if I ever had a time period of not enough sunlight, just shut the power off and buy some ice.
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