Any suggestions for solar power at a mooring. I would like to keep my refrigerator going so I o not have to lug the cooler every weekend to the boat. Thanks Richard (Duke)
Solar Power At Mooring
- Thread starter Duke13540
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I'm with Landsend...
Take your fridge current draw and multiply that by the number of hours of use and you will get amp hours you'll need from the batteries. Then size the battery at least twice that. Then size your panel so that over the week you will replace at least 125 percent of what you took out - even on cloudy days. My guess is that after you calculate that and the costs, the cooler is going to seem just fine after all! For a fridge, the better alternative would be to get a larger alternator, and increase the battery capacity so that you have to re-charge maybe every 12 hours or so.
Take your fridge current draw and multiply that by the number of hours of use and you will get amp hours you'll need from the batteries. Then size the battery at least twice that. Then size your panel so that over the week you will replace at least 125 percent of what you took out - even on cloudy days. My guess is that after you calculate that and the costs, the cooler is going to seem just fine after all! For a fridge, the better alternative would be to get a larger alternator, and increase the battery capacity so that you have to re-charge maybe every 12 hours or so.
On a mooring you have to go between the shore
and the boat anyway to get the stuff the you want to put in the fridge to the boat. So, it seems to me it's simply a matter of timing, and you may not need to lug a cooler, but what would you bring the stuff over to the boat with or in anyway? Reason I ask is that we never leave our boat plugged in, we have a slip with power and I never use the fridge unless we're there. When we go for a trip I bring cold stuff from home, leave bulky coolers at home just use bags, and turn the fridge on the boat on when I get there. We have plenty of stuff on board (like drinks) that get cold quickly. It takes about a half an hour to get the fridge cold. So, it seems there are a number of different approaches. I agree with Landsend and GuyT and if you want to try that approach you will need to do an energy budget and size the panels and your solar bank properly. Nigel Calder's "Cruising Handbook" has an especially good description of how he sized his system to permit seven days away from the boat. Of course, if you do what you plan, then you'll need to never miss a weekend (or however large you size your system) or else your batteries will go well below recommended discharge levels and/or your fridge will shut down on low voltage, obviating the whole concept to begin with. Good luck, but I'd like to understand why doing this would improve anything. I'm not at a mooring, so I don't perhaps understand the "transportation" and fridge on during the week issue at all.
and the boat anyway to get the stuff the you want to put in the fridge to the boat. So, it seems to me it's simply a matter of timing, and you may not need to lug a cooler, but what would you bring the stuff over to the boat with or in anyway? Reason I ask is that we never leave our boat plugged in, we have a slip with power and I never use the fridge unless we're there. When we go for a trip I bring cold stuff from home, leave bulky coolers at home just use bags, and turn the fridge on the boat on when I get there. We have plenty of stuff on board (like drinks) that get cold quickly. It takes about a half an hour to get the fridge cold. So, it seems there are a number of different approaches. I agree with Landsend and GuyT and if you want to try that approach you will need to do an energy budget and size the panels and your solar bank properly. Nigel Calder's "Cruising Handbook" has an especially good description of how he sized his system to permit seven days away from the boat. Of course, if you do what you plan, then you'll need to never miss a weekend (or however large you size your system) or else your batteries will go well below recommended discharge levels and/or your fridge will shut down on low voltage, obviating the whole concept to begin with. Good luck, but I'd like to understand why doing this would improve anything. I'm not at a mooring, so I don't perhaps understand the "transportation" and fridge on during the week issue at all.
Moving heat around
Anything that moves heat around using electricity is going to use a lot of it by boat standards. To wit: 5 amp draw on an at operating temp reefer (includes the compressor and cooling water pump) 50% duty cycle (reefer motor is on 50% of every hour) 24 hours in a day yealds 5*0.5*24= 60 A-H consumed every 24 hour period But you have to recharge the batteries during the day so 0900-1700 --> 8 hours effective charge time (effective because you are not going to be reorinting the panels to face the sun and they will most likely be laying flat on the boat and not aimed 90 degrees to the sun). 95% charging effeciency 60 A-H charge desired (not bilge pump or anchor light???!!) yealds 60/(0.95*8)= 7.9 amps continously supplied by the solar cells for the 8 effective hours they are in operation. The real output would be a trickle at dawn and dusk and ramp up to something less that 7.9 for the rest of the day. Solar cells are not sold by the amp however so we need to convert to watts 7.9 A * 14.7 volts (charging voltage) = 116 watts I think you would have to buy what is avalable so a 125 watt panel(s) should suffice assuming you don't run the bilge pump and anchor light. You only need to run off the batteries from 1700-0900 (effective) so 16 hours or 60*(16/24)=40 A-H from the batteries so buy 80 A-H worth at least, 100 would be a better idea IMHO now if you live in the desert and it never rains you are set. If it is overcast on occasion then you need to up the size of your solar cells to get enough watts every day to feed the reefer. Also only buy "36 cell" solar cells. Fewer cells will not charge the battery at 14.7 during the hot part of the day and you will get less than satisfactory results. Warm beer is no laughing matter!
Anything that moves heat around using electricity is going to use a lot of it by boat standards. To wit: 5 amp draw on an at operating temp reefer (includes the compressor and cooling water pump) 50% duty cycle (reefer motor is on 50% of every hour) 24 hours in a day yealds 5*0.5*24= 60 A-H consumed every 24 hour period But you have to recharge the batteries during the day so 0900-1700 --> 8 hours effective charge time (effective because you are not going to be reorinting the panels to face the sun and they will most likely be laying flat on the boat and not aimed 90 degrees to the sun). 95% charging effeciency 60 A-H charge desired (not bilge pump or anchor light???!!) yealds 60/(0.95*8)= 7.9 amps continously supplied by the solar cells for the 8 effective hours they are in operation. The real output would be a trickle at dawn and dusk and ramp up to something less that 7.9 for the rest of the day. Solar cells are not sold by the amp however so we need to convert to watts 7.9 A * 14.7 volts (charging voltage) = 116 watts I think you would have to buy what is avalable so a 125 watt panel(s) should suffice assuming you don't run the bilge pump and anchor light. You only need to run off the batteries from 1700-0900 (effective) so 16 hours or 60*(16/24)=40 A-H from the batteries so buy 80 A-H worth at least, 100 would be a better idea IMHO now if you live in the desert and it never rains you are set. If it is overcast on occasion then you need to up the size of your solar cells to get enough watts every day to feed the reefer. Also only buy "36 cell" solar cells. Fewer cells will not charge the battery at 14.7 during the hot part of the day and you will get less than satisfactory results. Warm beer is no laughing matter!
The path to wealth;
Invent the perfect refer system; Cold all the time and no power needed. Oh wait! It's been done. RV's have 'em. They use propane to cool. Of course they need to be level and there's something about that open flame aboard a boat that just doesn't set well with most folks.
Invent the perfect refer system; Cold all the time and no power needed. Oh wait! It's been done. RV's have 'em. They use propane to cool. Of course they need to be level and there's something about that open flame aboard a boat that just doesn't set well with most folks.
Bill..
While your math works out fine, real life, and math, when it comes to solar cells, do not always agree. I just came back from my boat, slightly over cast, 2:00 sun, and she was putting out .4 amps with no loads on. This is more the reality than then math would lead one to believe.. With solar I do my math using 4 hours of peak sun as a built in security blanket. So 60 amps divided by 4 hours gives you a 15 amp array. Overkill? Maybe, but it's better than cutting it close and killing a $1000.00 bank of batteries... I monitor my panel constantly, with a Xantrex XBM, and I can assure you that it does not put out anywhere near it's rated power for anywhere near 8 hours a day. When I'm on the boat I have my panel set up so I can angle it towards the sun and that usually yields another 20% or so depending on time of day.. Many of these solar sites are a little giddy and optimistic with their "sun math" to get folks to invest. The reality is much different, at least here in Maine.. I'm guessing they do all their testing in Arizona or something using A-1 perfect cloudless days...
While your math works out fine, real life, and math, when it comes to solar cells, do not always agree. I just came back from my boat, slightly over cast, 2:00 sun, and she was putting out .4 amps with no loads on. This is more the reality than then math would lead one to believe.. With solar I do my math using 4 hours of peak sun as a built in security blanket. So 60 amps divided by 4 hours gives you a 15 amp array. Overkill? Maybe, but it's better than cutting it close and killing a $1000.00 bank of batteries... I monitor my panel constantly, with a Xantrex XBM, and I can assure you that it does not put out anywhere near it's rated power for anywhere near 8 hours a day. When I'm on the boat I have my panel set up so I can angle it towards the sun and that usually yields another 20% or so depending on time of day.. Many of these solar sites are a little giddy and optimistic with their "sun math" to get folks to invest. The reality is much different, at least here in Maine.. I'm guessing they do all their testing in Arizona or something using A-1 perfect cloudless days...
Any thought about Wind
I am new to boating and have really enjoyed reading all the advice given. I will also be on a mooring but unfortunately spent my budget upgrading the electronics (chartplotter/radar). Next season I will increase my house bank. How does Air-X wind power compare to solar? Is it noisy? Seems like there are alternatives.
I am new to boating and have really enjoyed reading all the advice given. I will also be on a mooring but unfortunately spent my budget upgrading the electronics (chartplotter/radar). Next season I will increase my house bank. How does Air-X wind power compare to solar? Is it noisy? Seems like there are alternatives.
Wind vs Solar
bsmith, this could lead to as big a discussion as which is the best boat for, fill in the blank. It depends on a lot of different things, and different opinions. If you live in an area with a lot of sunshine, and not much wind, then go solar. If you live in an area with good constant breezes, then solar might be the way to go. I had a 250 watt wind gen. on my 28 before Katrina, and loved it. But I was using no fridge. The deciding factor will be your power consumption, and how much power you need. The Air-X is rated at 400 watts, but like the solar panels, the is the max. output at 28 knots of wind. So the best answer I can give you is do your research, and decide which is best for you and the area where you live.
bsmith, this could lead to as big a discussion as which is the best boat for, fill in the blank. It depends on a lot of different things, and different opinions. If you live in an area with a lot of sunshine, and not much wind, then go solar. If you live in an area with good constant breezes, then solar might be the way to go. I had a 250 watt wind gen. on my 28 before Katrina, and loved it. But I was using no fridge. The deciding factor will be your power consumption, and how much power you need. The Air-X is rated at 400 watts, but like the solar panels, the is the max. output at 28 knots of wind. So the best answer I can give you is do your research, and decide which is best for you and the area where you live.
check out the D400 wind generator
I've been doing a lot of research about wind generators recently. Nice thing about wind generators is that they always point to the power source, and that they'll work at night. The Air-x is relatively noisy and needs a bunch of wind before it will provide any appreciable amperage. Better is the Rutland 913, which seems to be the most quiet unit made. But the D400, only slightly more noisy, seems to put out twice the power. Costs twice as much as well, but it seems to be the direction I'm moving in.
I've been doing a lot of research about wind generators recently. Nice thing about wind generators is that they always point to the power source, and that they'll work at night. The Air-x is relatively noisy and needs a bunch of wind before it will provide any appreciable amperage. Better is the Rutland 913, which seems to be the most quiet unit made. But the D400, only slightly more noisy, seems to put out twice the power. Costs twice as much as well, but it seems to be the direction I'm moving in.
When it comes to wind generators also consider
that all of the best anchorages are hidden to block wind and waves. And most cruisers voyage downwind and see much less apparent wind at the generator. Again, it's about your personal cruise style.
that all of the best anchorages are hidden to block wind and waves. And most cruisers voyage downwind and see much less apparent wind at the generator. Again, it's about your personal cruise style.
You might also check
Air X has a new model out, that is I think 200 watt. Going to be handled by West Marine. Don't know much about them and don't remember what they are called, but depending on your power needs, might be worth a look.
Air X has a new model out, that is I think 200 watt. Going to be handled by West Marine. Don't know much about them and don't remember what they are called, but depending on your power needs, might be worth a look.
- Jan 22, 2008
- 519
alternative thinking
Here is a slightly different line of thought. I am a minimalist, and sail a 20'er so take that into consideration when reading my advice. I have always found that with issues of power consumption, the goal is to reduce the demand, not increase the availability. Increasing availability, always costs more, requires more equipment, is more likely to break down and parts are increasingly interdependent on one another to function. For example in your case the panel, sky, regulator, batteries, and fridge must all be working cooperatively to keep your brew cold. Any failure in any one part of the system, and the brew is not cold. Think reducing consumption. You are only there on weekends anyhow, according to your original post, so no need to have the boat keep your brew cold for you. (I use brew here as the example, knowing full well that there are other items you want to keep cold as well, but I'll keep brew as the example). Instead have your home fridge, store, or whereever keep the stuff cold until you need it. Even using a coolatron (12 volt cooler with 115 volt converter) at home to keep your brew cold, only requires your house current. You can keep adding items to your cooler all week as you acquire products to throw into it, or as you think of it. Come the weekend, grab the coolatron, plug it into your car lighter for the trip to the boat, then plug into the 12 volt power outlet on your boat for the weekend. A regular battery will keep that coolatron working all weekend and your brew cold. You won't need a panel, sky, regulator or separate fridge to keep your brew cool. If your battery is not charged by your motor, you could always add a small (15 watt) panel to keep it charged, but we have kept the koolatron going for a 3 day weekend without issue on a friends 24 and 30'er with two people aboard. We also freeze water in gallon milk containers and add them to the ice box (not coolatron) to keep itself and other items cold, (milk, juice, pop, eggs, cheese etc) I am even more of a minimalist on my own 20'er. I use a portable soft sided cooler that I keep my cold essentials in, then slip it into the ice box on the boat. The extra insulation, plus cold packs keeps things cool for the whole weekend. I typically use foods that do not need refrigeration so again reduce the consumption need. Our marina also has cold storage, so I can keep a supply of stuff there from week to week, and have their electrical system keep my stuff cold rather than relying on my boat systems to to that work.
Here is a slightly different line of thought. I am a minimalist, and sail a 20'er so take that into consideration when reading my advice. I have always found that with issues of power consumption, the goal is to reduce the demand, not increase the availability. Increasing availability, always costs more, requires more equipment, is more likely to break down and parts are increasingly interdependent on one another to function. For example in your case the panel, sky, regulator, batteries, and fridge must all be working cooperatively to keep your brew cold. Any failure in any one part of the system, and the brew is not cold. Think reducing consumption. You are only there on weekends anyhow, according to your original post, so no need to have the boat keep your brew cold for you. (I use brew here as the example, knowing full well that there are other items you want to keep cold as well, but I'll keep brew as the example). Instead have your home fridge, store, or whereever keep the stuff cold until you need it. Even using a coolatron (12 volt cooler with 115 volt converter) at home to keep your brew cold, only requires your house current. You can keep adding items to your cooler all week as you acquire products to throw into it, or as you think of it. Come the weekend, grab the coolatron, plug it into your car lighter for the trip to the boat, then plug into the 12 volt power outlet on your boat for the weekend. A regular battery will keep that coolatron working all weekend and your brew cold. You won't need a panel, sky, regulator or separate fridge to keep your brew cool. If your battery is not charged by your motor, you could always add a small (15 watt) panel to keep it charged, but we have kept the koolatron going for a 3 day weekend without issue on a friends 24 and 30'er with two people aboard. We also freeze water in gallon milk containers and add them to the ice box (not coolatron) to keep itself and other items cold, (milk, juice, pop, eggs, cheese etc) I am even more of a minimalist on my own 20'er. I use a portable soft sided cooler that I keep my cold essentials in, then slip it into the ice box on the boat. The extra insulation, plus cold packs keeps things cool for the whole weekend. I typically use foods that do not need refrigeration so again reduce the consumption need. Our marina also has cold storage, so I can keep a supply of stuff there from week to week, and have their electrical system keep my stuff cold rather than relying on my boat systems to to that work.
Data Point
I have a Kyrocra 85 watt solar panel, two Morningstar Sunsaver-10 charge controllers feeding four Trojan 105's and a pair of Trojan group 31 starting batteries. I have a new Adler Barbour cold machine, and I added insulation to my circa 1980 icebox. Not a bad setup. So what happened when I left my fridge on by accident last fall. It ran about four weeks and ran out of juice. I certainly would not run it over the winter on the mooring, not enough light.
I have a Kyrocra 85 watt solar panel, two Morningstar Sunsaver-10 charge controllers feeding four Trojan 105's and a pair of Trojan group 31 starting batteries. I have a new Adler Barbour cold machine, and I added insulation to my circa 1980 icebox. Not a bad setup. So what happened when I left my fridge on by accident last fall. It ran about four weeks and ran out of juice. I certainly would not run it over the winter on the mooring, not enough light.
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