Richard, I don't have water cooling - Marvin didn't recommend it for
northern waters. The 50 AH is my total load, including lights, etc.
It's hard to tell what the compressor load on its own is, but it
appears to run about 50% of the time, perhaps somewhat less. I've
built a microprocessor-controller thermostat that records run times,
etc, for use next season, so I'll have more information and better
control than the mechanical thermostat.

I disabled the "speed control" on the EZKold soon after I installed
the system, as I found that the compressor ran more or less forever.
But I think I was trying to keep things too cold back then. I replaced
it with a 1500 ohm resistor, to let the compressor run at full speed.
But I gather from reading your web site that effeciency may increase
by matching the compressor speed to the box. I think I will install a
variable resistor in the new controller (or maybe have the computer
switch in different values) so that I can try to optimize things.

Given the situation for my system, any suggestions as to what level I
should try to run the BD35 at?


(Richard Kollmann) wrote:

Larry, Thanks for providing information on solar power and
refrigeration at 40 degrees north. There are new BD35 compressors with
controllers that no longer need a battery's narrow voltage range to
operate. These new controllers are reported to be able to maintain
compressor speed with solar panel voltages from 10 to 45 volts, as
long as there is sufficient amperage. So the question will be, will
these new units use less amp hours, if three 12 volt panels are
connected in series.

I was surprised by your 50 amp-hrs per day until I saw that you were
using an EZ Kold unit. A 4.5 cu. ft. refrigerator with three inches of
good insulation in your cruising area, should consume no more than 30
amp-hrs per day.
Try this the next time you go cruising, disconnect the power to the
speed-up unit and use air cooling instead of water. The speed-up unit
destroys the coefficient of performance (COP) of the BD35 condensing
unit and the water pump current drain is not necessary. The compressor
may run longer but will only draw ½ the current.
Let us know what you find out.

http://www.kollmann-marine.com

Larry Bradley VE3CRX
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Ottawa, Canada

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