Is Your Boat Self-Sustaining Electrically?

[SURV69]

In dock I don't have to worry about it.

BUT I want my boat to be self-sustaining & self sufficient, electrically.

I want to be able to sit at a dock, or at anchor with absolutely no difference in my daily electrical usage. Or, for that matter all my daily regimen.

Soon, I'll be looking into solar panels and expect to buy a couple of 185+ watt panels for my boat(Newport 28) to keep my batteries topped off.

I'm in the process of changing all my lights to LED and chucking almost all my navigation electronics. I'll keep equipment that runs "efficiently" off of AA batteries. Even then, I expect to have a couple of small solar panels for the recharging of AA batteries and such.

I just can't stand the idea of plugging my boat in any more.

[Hudson Force]

It depends....! It depends on what I'm doing with my boat. If I keep my freezer/refrigerator on, then I need more than my wind generator and my solar panel. If my freezer/refrig. is not operating, then I can last indefinitely. I do have a 7Kw diesel generator, solar panels, wind generator & alternator from propulsion engine. There are too many variables to answer this question and everyone is subject to these variables. Almost everyone's biggest power pig is the refrigeration. If you plan to be aboard without a freezer or refrigeration, it's easy!

[sww914]

If it's sunny most of the time we can waste electricity running the PS3 and the icemaker. We have 3 190 watt panels, a fridge, a big inverter, electric water pump, etc., bu we have converted all the interior lights to LED.

[SURV69]

WOW

only used a little over 2k watts total each month when I had a mobile home.

BTW . . . I'm interested in a cooler, but not a refrigerator & freezer.

Even my TV(which I rarely watch), is a 3-1/2" unit.

[thinwater]

Originally Posted by SURV69

WOW

only used a little over 2k watts total each month when I had a mobile home.

BTW . . . I'm interested in a cooler, but not a refrigerator & freezer.

Even my TV(which I rarely watch), is a 3-1/2" unit.

With your habits and boat, this seems very attainable. You arn't greedy.

First, create and "energy budget." If you have an amp meter in the panel, that will hint at your usage. Or you can simply add up everything you use (watts x hours) and multiply by about 2 to allow for losses, cloudy days, and some rig shading. Then divide by 5 hours, since on the average, counting in low sun angles, that is what panels give you.

For example:
40 W x 4 = 160 W-hr
10W x 10 = 100 W-hr
Total = 260 W-hr
Times 2 = 520 W-hr

if only 5 hours of sun are counted, a 120 W panel would do.

Another way is to see how long it takes to drop your batteries a certain amount. It's more honest in some ways, but you need to look at a capacity vs voltage chart, know the life of your battery well, correct for temperature... well, it gets a bit convoluted.

I'm guessing you need less than you think, perhaps 3 batteries and a single 185 W panel. I have 2 x 85 W and a MUCH larger electricity budget. They are not enough for me, but I run a fridge, fans, incandescent lights, nav and autopilot, DVD... a lot more.

Sail Delmarva: Solar Panels

If I lived aboard I would add some panels, but as it is we don't need to plug-in unless we run the AC.

[janice142]

Not quite, but close. If the wind blows the reefer is on, otherwise (until I can afford another 225 watts of solar, bringing us to 300 total) the refrigerator is turned off and we buy ice. This is not economically the best solution (more solar would be) but it is what works.

And yes, we could run the engine to charge via the alternator but the idea of running the engine and going nowhere simply doesn't sit well with me.

Your stated plan has always been the goal and we are closing in on totally 100% self-sufficient for power. The latest LED lights (bought off eBay by a neighbor boat) draw .01 amps (yes, it takes four days to almost use a single amp!!!) and the Owl anchor light Bebi Electronics-Home of the Finest Marine LED Lighting Products on Sea (or Earth)! are both components of our power saving plan.

Surv69... you might also consider a 12 volt recharger for your AA batts and then simply run that off a cigarette lighter outlet. How large a battery bank do you have?

[Bash]

Yes and no. With 200 watts wind + 260 watts solar, I can stay on the hook indefinitely without my batteries ever getting low, even when running cabin fans, a separate refer and freezer, et cetera. However, I have no way at that point to heat hot water and I have to rely upon a diesel furnace to heat the cabin during winter months. We make do with a solar shower during summer cruises, and often end up heating dishwater via propane with the tea kettle.

To me, total self-sufficiency would mean being able to use renewable energy to supply hot water through the pressurized fresh water system.

[SURV69]

Almost all of my "minimal needed" electronics run off of 2-4 AA batteries.

Right now I have 2 size 29 batteries(deep cycle-flooded).

I have a 20 amp charger(120 volt), but I rarely, very rarely use more than my puck LED's(not bright but very low amps).

My music comes from a 5 volt "mini box", that runs on it's internal batt for about 2-3 hours before I have to supplement it(it also plays mp3's).

My 3-1/2" TV uses 5 volts too.

I just changed my navigation lights to LED and am about to supplement my puck LED's with 167 lumen lights(2 watts each). I have 10 of these buggers, but generally speaking the puck lights work well for about a week at a time(they also plug into 120 volt).

I've ALWAYS been frugal with resources. Even when I was young, I used ground electricity(copper & zinc rods) instead of batteries for my experiments.

Using more than the bare necessity has, for some reason always bothered me . . . even when gas was 25 cents a gallon(1968-9).

I'm definitely a minimalist........

[SURV69]

sorry . . .

The reason for the small panels is portability and the idea that I can always find small spaces that will give full sun.

[sailorchic34]

Mine is on a total of 230 watts in 2 panels. My load is a 120V 3.5 cf fridge, led and cca lights, fan for summer, cell and netbook and led anchor light. Figure I get about .8kw a day which just matches my daily requirements. Least in the summer. I'll see what happens this winter with less sunlight. Probably a little shy, I guessing.

[daddle]

Yes. Unless it rains for 3 days. Then the diesel needs to run a bit. 240W of panels. Tropical sun. Fridge, lights, computer charging, fans.

Underway with the A/P driving and instruments on is a little bit harder to achieve independence. And some panels are often shaded by sails rig or whatever.

[sv Winterlude]

We have a 37' Passport with a small freezer & refrigerator (Adler Barber) which is by far our biggest amp hog. We figure 6-7 amps every other hour for a total of 84+ amp hours a day of refrigeration -- but sometimes it doesn't cycle, and then we have more like 120 amp hours of refrigeration. We have 6 Trojan T-105 6v batteries and amp hours to spare, but with 225 volts of solar and a KISS wind generator, we need more ... more like 450 volts of solar. We also have a Honda 2000 generator to run when there's no wind and sun. We run it as little as we can. If the wind's blowing 15 and the sun's blazing, we might get away with being down as little as 35-50 amps overnight, but more usually we're down over 100 amps in the am and have to play catch up all day. We figure that anyone who claims much less either has a MUCH smaller boat, is willing to run the diesel (which we're not) or ....... ???? We realize we're not the least amp boat, but we have sensibulb LED lights, no tv, nothing after dark, not much other than the fridge, VHF and SSB - sailmail, laptop only on when we're doing e-mail or weather, not much voice which is by far the bigger amp draw ... no real amp draws.... so... go figure...

[impi]

We are touring the world on our boat and when I started researching how to have a boat where I never have to think about enough electricity or water at sea, people laughed at me and said I would have to change my thought process. That was not the answer I was looking for and so set about to have my boat set up to handle the luxuries we wanted. We achieved it and I must say I am really pleased I pushed on despite being told I was crazy. In short we have a boat that generates power no matter what we do (except for the wind generator). We have 1000 AH House battery bank (deep cycle Gels), 5 x 135Kw Kyocera solar panels wired through a 50 amp Mppt Blue Sky controller, 2 x 150 AH Balmar Alternators(Smart charger) wired through a centerfielder combining the output if both engines are run, 2 x 3000a Victron Inverter chargers delivering 6KVA 220V power and charging at 240 AH, a 7/9KW genset feeding the Inverters, washing machine, dive compressors etc and we have a 12V Spectra MK2 Water maker making 70 ltrs water per hr using 18 AH. We wired up diodes and relay switches to the Mppt controller to shut off the solar panels when the engines switch is turned on so as to not confuse the charge rate of the Balmars (the Balmars are FANTASTIC ... my best source of quick charge by far). We run our 6KG washing drying machine through the batteries (inverters) without the genset having to be on. My logic? ... If we have sun, the solar panels push 40-50AH for the best part of the day (we seldom run anything else for power unless being extra heavy on electrical demand). If we start an engine we have the Balmars pushing 150 AH (theoretical) and if both engines run we get 300 AH (Theoretical) charging. If we use the genset, the two Victron inverter charges deliver a charge rate of 240AH (Theoretical) which requires little time on the genset. We make water every day, wash clothes, bed linen and dry it every 2nd day, run 2 fridges and a freezer, an ice maker, watch TV, run computers etc. etc. and the system really works well ... we NEVER think about energy consumption EVER, have hot water showers when we want and I wouldnt have it any other way! IT IS POSSIBLE. What would I do differently ... I would have added another panel to my 5 Kyocera solar panels and if possible another 2 or 3 ... that would have been 'over the top' fantastic!

[SunDevil]

I hope more boats are designed with this in mind in the future. There are quite a few things that could be done to have more power than you'll need all while living comfortably.

[denverd0n]

Originally Posted by SURV69

I'll keep equipment that runs "efficiently" off of AA batteries.

Are you going to have a 12 volt system, or run everything off of AA batteries? Sounds like it is going to work okay for you, but just so that you (and anyone else reading this) knows, if you have a 12 volt system anyway, it would be more efficient to find equipment that runs directly off of the 12 volts. That way you are only suffering the losses of the solar conversion and battery charging one time, in one place. If you are also charging AA batteries, then you are increasing the times and places where you suffer inherent losses.

It's a minimal issue, really, so this is kind of nit-picking, but if you are looking for the maximum efficiency from your electrical system it is something to consider.