To keep or not to keep.....

[Bonzai]

During my most recent work on Salacia the old non-functioning Lectra-San system has been completely removed and replaced with a fully manual Levac set up with holding tank/ Y-valve set up. Now being removed are the 10 gal. hot water heater and the electric pumps for both fresh and saltwater systems, the pressured systems to be replaced with foot pumps. I am going to be using an Aries wind-vane for breezy days and plan to attach a tiller pilot to the wind-vane for not so breezy days (this is an option to a more expensive/more power hungry auto-pilot I hear). As I see it...my 2 remaining big drains on my house batteries will be my older radar, which I may replace before it breaks with the newer broadband radar if I find a buyer for present system, and my refrigeration.
Now for my question......Currently I have a wind generator (30 amps) and 120 watt solar panel ( with less than perfect set-up...mounted fixed flat right between radar array and wind gen on tower on aft deck) , fridge compressor draws 28 amps I believe maybe a bit more and is spec to run 18% of the time at 86 F ambient temp. Cold box currently keeps 18 lb. bag of ice for over 5 days so I believe it to be well insulated. I REALLY want a good working fridge....but will I be able to run continuously while at anchor and under sail w/o having to use engine or portable gen I carry for A/C? Thanks!

 

[Stu Jackson]

Sure you will. It all depends on how long. Really. An energy budget including your storage capacity and charging input answers that question.

 

[Bonzai]

Sure you will. It all depends on how long. Really. An energy budget including your storage capacity and charging input answers that question.

Hi Stu, I just replaced all batteries, have 2 sets of 2 (4) house batteries @ 90 AH each, 360 AH total. New 135 amp alternator on engine.Replacing all lighting with LEDs is the plan also. I hope that the engine is running anytime I use the windlass so that shouldn't be a factor. I feel the fridge so necessary because the icebox space(s) pretty small and don't want to cut space by nearly half hauling ice.

 

[robertsapp]

Well, if your compressor is designed to draw 28 amps, and runs for 24 hours at an 18% duty cycle, it sounds like you're going to need about 120 amp hours a day. Your 120 watt solar panel might be able to come up with about half of that provided it's sunny all day and the panel isn't shaded. The rest is going to have to come from your wind generator. So it really just depends. If it's a very sunny, breezy day, you should be fine. If it's a foggy or overcast day with light winds, you'll need to supplement. Then there's the whole thing about all these other variables like what's the air temp today, what's the water temp, how good is the box insulation, is the box close to something like an oven or water heater that can add extra heat. These unknowns make it just about impossible to say with certainty that you'll be fine as long as you have "X" amount of sun or wind speed. Some days you'll most likely be good, others, you'll lose ground. Get a good battery monitor.

 

[Sumner]

..Currently I have a wind generator (30 amps) ..... fridge compressor draws 28 amps I believe maybe a bit more...

Have you double checked those two figures above. A wind generator capable of 30 amps output would have to be really large except if it was maybe putting that out in a gale.

Also most fridge compressors that I've seen or in the 3 to 6 amp draw range.

We got by with 180 watts of solar on the Mac for a couple months running a 63 quart Edgestar fridge, a lot of computer time and a CPAP machine at night. We still had to run the....

http://purplesagetradingpost.com/sumner/macgregor/outside-13.html

...gen-set for a couple hours (total run time) in those 2 months.

On the Endeavour the fridge...

http://purplesagetradingpost.com/sumner/endeavour-inside-mods/inside-index.html

...I built is larger than the portable but uses way less electricity due to the massive amounts of insulation that were used.

With an efficient fridge you could get by with 200 watts most of the time. We added...

http://purplesagetradingpost.com/sumner/endeavour-electrical/electrical-index.html

...480 to the Endeavour to make sure we wouldn't be running the engine to charge,

Sum

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[Bonzai]

Hi Sum! Great to hear from you. I checked the specs;
Specifications: Fully hermetic Danfoss BD35F compressor
Cools refrigerators up to 8.8 cubic feet
Deep freezing to 2.5 cubic feet
Voltage: 12/24 volts DC
Average power consumption: 45 to 60 watts, depending on the evaporator type ...so was watts not amps....>.<......... I carry the little 2000 watt Honda Gen/Inv for running the cabin AC and for emergency charging. Survey says 30 amp Windmachine wind generator. Hope you and crew are well..hope to see you on the water!..

 

[Stu Jackson]

With a reasonably insulated fridge, you will find your daily consumption is 100 A.

Also discussed in "Breaking In New Wet Cell Batteries," here: http://c34.org/bbs/index.php/topic,6353.msg41471.html#msg41471

With your LEDs, shouldn't be an issue.

STILL an issue as to how LONG you can stay out.

Do the math. That's as much as ANYONE can offer.

 

[Bonzai]

You are right on that Stu. Electrical is def not my forte, I just discovered that Watts= Amps X Volts, that and seeing that the power consumption was 45-60 watts not amps I know I am dealing with about 5 watt drain. No big deal. I hope to keep learning as I go. I appreciate all the help from you guys as always!

 

[Stu Jackson]

If you don't have it, and it used to be available online, try Charlie Wing's book, highly recommended.

 

[druid]

You can run the new Danfoss compressors easily on an 80W solar panel if it's more-or-less sunny. In the summer I ran my Waeco (now Dominec?) fridge and kept my batteries topped up at the dock on my 80W panel, so I didn't need shore power. Ran fine all summer, until someone ran his boat into the panel...

But like Stu says - you need to do an energy-balance calculation if you want to be sure.

druid