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So here's how last week's trial turned out. I ran the fridge to 29F in the freezer compartment, then moved the thermometer to the bottom of the icebox (thus the jump around 20:00). Looks pretty good that it stayed under 37F for ~80mins so it seems like i'll cycle for 10min/hour which is about what Isotherm predicts for a 20AH/day draw. Might even be a little less when we stuff it with frozen food.
Jeff
Jeff, that’s really interesting. The graphs are amazing. Seems like that is useful info especially in the beginning as you get a feel for the parameters.
But there are two pieces of info that seem important as sailors consider such an upgrade: how air and water temp effect aH requirements.
Seems like both of those parts of the equation are as important as icebox thermal efficiency. It would seem 70° air and 60° water temp would yield different aH per day results than say 85° air temp and 80° water temp.
What sailors were telling me in the Caribbean tended to be in the 40 to 70 aH per day. I don’t know much about the thermal efficiency of their boxes though. Lots of other variables too. What are your thoughts about it?
Will be very interested to learn more about your experience with the isotherm and your thoughts about it at the end of the season.
Thanks John! I found it interesting too.
It was a warm day for May but the water temp is still around 50F here, maybe a little cooler that day.
It's interesting how much of the CD30 icebox lies against the hull so the water temp is a strong factor. And sharing thre next largest side with thre engine compartment is another problem.
I'll keep you posted on how it works out.
Jeff
First of all, I have to apologize about a lack of good data this summer. My first mate has been unable to sail which has really interfered with my data collection.
In our cool New England water, at least from Salem to Rockport, the cooler has kept up and at a fairly low power level. I'm pretty sure I'm less than 20aH/ day which would match the vendor's claims.
I'm sitting on the boat now and listening to the compressor cycle on for about 5 min every 20-25 mins. That's in 65 degree air and 70 or so water.
Jeff
I ran the fridge to 29F in the freezer compartment, then moved the thermometer to the bottom of the icebox (thus the jump around 20:00). Looks pretty good that it stayed under 37F for ~80mins so it seems like i'll cycle for 10min/hour which is about what Isotherm predicts for a 20AH/day draw. Might even be a little less when we stuff it with frozen food.