Solar power ~ no more running the engine - Page 11 - SailNet Community
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Re: Solar power ~ no more running the engine

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Originally Posted by hellosailor View Post
"Also... my mac has a 240v supply rather than 110v (just to throw another variable in) "
Watts is Watts, David. they don't care about Volts.
ok
my mistake.

I am struggling to wrap my head around the relationships between amps vs volts vs. watts TBH

Anybody recommend any reading materials to help me to elevate my level of understanding?

Electrics for dummies perhaps???
DavidB.UK is offline

Old 07-16-2012
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Re: Solar power ~ no more running the engine

Quote:
Originally Posted by DavidB.UK View Post
ok
my mistake.

I am struggling to wrap my head around the relationships between amps vs volts vs. watts TBH

Anybody recommend any reading materials to help me to elevate my level of understanding?

Electrics for dummies perhaps???
Amps measures "current"
Volts measures "electrical force"
Watts measures "power" consumed

If you were drinking an electrical milkshake (alcoholioc of course since this is sailing) the Amps would be how fast you were sucking on the straw, the volts would be how much sugar was in the milkshake and the watts would be the resulting calories (impacted by both the speed at which you sucked it through the straw and the amount of force / sugar - thus AxV=W or in traditional terms I (current) *V (voltage)=P (power)

You'll probably need your own metaphor but you'll get it.
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Re: Solar power ~ no more running the engine

Quote:
Originally Posted by blowinstink View Post
Amps measures "current"
Volts measures "electrical force"
Watts measures "power" consumed

If you were drinking an electrical milkshake (alcoholioc of course since this is sailing) the Amps would be how fast you were sucking on the straw, the volts would be how much sugar was in the milkshake and the watts would be the resulting calories (impacted by both the speed at which you sucked it through the straw and the amount of force / sugar - thus AxV=W or in traditional terms I (current) *V (voltage)=P (power)

You'll probably need your own metaphor but you'll get it.
That's a great mteaphor, made me chuckle. Thank you
DavidB.UK is offline

Old 07-16-2012
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Re: Solar power ~ no more running the engine

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Originally Posted by hellosailor View Post
Mystery eBay controller, what brand is that? The Genasun MPPT controllers are about the least expensive on the market and they are well more than that.

Most marine alternators, possibly "all" production boats, aren't really installed the way the alternator makers would recommend. In a car, one set of fan blades may be enough, but for marine use or heavy-duty use, many of them recommend dual fans and specific models allow for the use of one set of blades in front of the alternator and the second set behind it. Apparently once the frame heats up, you're toast, so to speak, so ducting in cool air probably would be the most effective way to increase alternator output on a boat. I've wondered if having an alternator body fluted by a machine shop would create more problems than it solved--but fluting any metal surface is also a great way to get better heat transfer.

A lot of laptops run 100/110W power supplies these days. Remember that the power supply needs to provide roughly twice as much power as the laptop consumes. Half of that runs the laptop (including spinning drives and a bright screen) while the other half is only used when the battery needs charging. Run on AC all the time, and you only need half of the power supply's max power. Run while you're recharging the battery, and you need it all.

That the laptop supplies are often rated 16-19vdc baffles me. I've asked around and never gotten an answer, or even a speculation, on why they need that voltage. Laptop batteries seem to top out around 12 volts (nominal) so in theory, all they would ever need is a 14.4 volt charger. 16 might be justified as conservative design, but by the time they get to 19...no one knows why, and the makers don't talk to civilians. The old Toshibas and IBMs that used to get chosen on boats because they ran directly on 12 volts, are long gone AFAIK. And meanwhile, nothing in the laptop should "need" more than five volts really to run these days. Baffling.

Thank god these same folks haven't had any interest in redesigning pens and pencils. Although, when I see a four-pack of ballpoints with a \$6.49 price tag on them, I really have to wonder who drugged my KoolAide.

OK, first thanks for your reply. The so called MPPT that I purchased is found at:

www .ebay.com/itm/180890446908?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Not sure if posting URLs is permitted so you might need to add the hppt stuff and delete the space after the www.

How it performs remains to be seen. I selected this model for price plus I did not want the electrical noise that a buck converter generates.

Alternators--- cooling is a must! Years ago in another life, I found many high voltage, high power devices were water cooled. I often wonder why alternators at least the high power units for marine use are not water cooled. Some of the methods are simple such as wrapping a copper tube around the outer periphery of the case. Sure, it needs to be secured for heat transfer, soldering or brazing would be almost impossible in the field but not in a manufacturing facility.

Foggy
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Old 07-16-2012
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Re: Solar power ~ no more running the engine

Quote:
Originally Posted by blowinstink View Post
Amps measures "current"
Volts measures "electrical force"
Watts measures "power" consumed

If you were drinking an electrical milkshake (alcoholioc of course since this is sailing) the Amps would be how fast you were sucking on the straw, the volts would be how much sugar was in the milkshake and the watts would be the resulting calories (impacted by both the speed at which you sucked it through the straw and the amount of force / sugar - thus AxV=W or in traditional terms I (current) *V (voltage)=P (power)

You'll probably need your own metaphor but you'll get it.
Okay, try voltage is analogous to the alcohol content (proof) of the drink, amps is speed with which you down shots or glasses, and watts is the resulting hangover.

Nice metaphor dude!

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Old 07-16-2012
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Re: Solar power ~ no more running the engine

I think of Amps vs. Volts vs. Watts like water flowing through a pipe.
"D" = Pipe diameter = Volts
"S" = Speed of water flow = Amps
"F" = Overall throughput = Watts.

If we want to attain overall throughput of "F", we can use a big pipe with slow flow or a skinny pipe with a fast flow. A bigger pipe = less pressure to attain "F". If you go with a skinnier pipe, you must increase "S" to attain "F", but this results in higher pressure.
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Re: Solar power ~ no more running the engine

Quote:
Originally Posted by foggysail View Post
OK, first thanks for your reply. The so called MPPT that I purchased is found at:

www .ebay.com/itm/180890446908?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Foggy
I am not a mod but links seem to be ok as long as you are not promoting your own products and it is relevant to the thread
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Old 07-16-2012
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Re: Solar power ~ no more running the engine

Quote:
Originally Posted by blistovmhz View Post
I think of Amps vs. Volts vs. Watts like water flowing through a pipe.
"D" = Pipe diameter = Volts
"S" = Speed of water flow = Amps
"F" = Overall throughput = Watts.

If we want to attain overall throughput of "F", we can use a big pipe with slow flow or a skinny pipe with a fast flow. A bigger pipe = less pressure to attain "F". If you go with a skinnier pipe, you must increase "S" to attain "F", but this results in higher pressure.

I don't get it. How many proof is the "water"?
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Old 07-16-2012
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Re: Solar power ~ no more running the engine

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Originally Posted by wingNwing View Post
Okay, try voltage is analogous to the alcohol content (proof) of the drink, amps is speed with which you down shots or glasses, and watts is the resulting hangover.

Nice metaphor dude!
Now, there's a sailor!
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Old 07-16-2012
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Re: Solar power ~ no more running the engine

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Originally Posted by Cruisingdad View Post
As Wing-N-WIng stated, I am surprised at some of these responses.

Our boat has been off the grid for years now. We have refrigeration, radio, some LED lights, use several home-style lamps, electric heads, water pump, etc. We have a 2000 watt Prosine Inverter. THis runs the microwave, cofee pot, lamps, etc.

We live very comfortably. Our boat does have air conditoining, but we cannot run that off of solar. Not a big problem most of the time as we put up sun shades and open all the hatches and get a nice breeze.

Our setup is the following:

4 - 130W Kyocera SOlar Panels on top of a dedicated solar arch.
4 - 4-D Lifeline AGM batteris for the house bank, totalling 840 ah.
1 - Outback MPPT MX60 SOlar CHarge Controller
1 - Xantrex Prosine 2.0 (2000 watt) Inverter/charger
1 - Mastervolt 3.5 kw Diesel Generator

We use, ballpark, 160-180 ah day on the hook. THis does not include AC, of course. We generate, 200-220 ah in solar/day. We have generated more solar than this and we have used more power than 180 ah/day... but these are good averages and being very reasonable.

You do get the cloudy days which drops the output of solar down considerably. THat is why we also have a very large batery bank to get us through those days. The trick is over sizing your battery bank and oversizing your solar panels so that you can make it through the cloudy days.

The wife and I recently agreed that the solar setup is the best thing we have put on the boat. It is quiet and watches out over itself. THere is no maintenance and it is completely trouble free. However, it is very expensive.

Diesel will have to get really expensive before it becomes economically viable to take solar over running your main. Now, if you throw a diesel generator in there, then all bets are off as you can easily rack up \$15000 on a diesel generator installed. But my solar investment is as follows:

\$3750 for custom solar arch, installed.
\$650ish/panel for a total of \$2600
\$400ish for the Outback MPPT solar charge controller
\$300ish in wire and fittings.

All together, I am ballpark: \$7000 dollars into this solar setup. THat is a LOT of diesel in your main engine. THis also does not count the 1600 or so dollars in batteries (which I got at a steal). So a high end solar setup is not cheap and I think anyone would have a tough time making a good economical decision from it. But like I said, it is awesome now and the best thing I have put on my boat. It makes us fairly worry free about our energy budget. And should we ever want, we can crank up the generator and have air conditioning down below and charge the batteries that way.

As far as saving energy, WIng-N-WIng was right again about the coffee pot. We do use an electric coffee pot, but have a bodum also. If you are going to use an elecric, we found that the carraffe style coffee pots are the best because then you are only paying for the electricity to make it - not keep it hot. At the very least, when you are done making coffee, turn it off and pour it into a carraffe.

LED lighting helps, but is also expensive. Look into lamps with CFL or LED bulbs that you can buy at Costco inexpensively as another option. What we do is everytime a halogen bulb goes out, we replace with a LED.

ANother energy saving tip is replacing your anchor light with an LED light. THat is a lot of energy going to waste up there for those that anchor out a lot like us.

THe refrigeration is going to be one of the largest consumers of electricity. I personally would never cruise without a fridge and freezer. It makes life much more enjoyable. A very cheap way to decrease your electrical use on your friedge is to go to Lowes and buy styrofoam sheets. THey are cheap and come in long runs. Cut them to fit into your box. Before taping them into the inside, completely wrap them in Foil Duct tape. THis reduces the mold, makes it easier to clean, and makes them last longer. If you have a top opening fridge, make panels that sit across the top with at least two openings. THat way, when you want to open the fridge to get something out, you open it, then pull out only one panel which reduces the exposure and keeps more cold air in. If you have a front door opening style, do the same - but also add in thin hanging sheets of plastic that you have to reach through to get to your stuff. You can see through it but at least when you open the door, you don't dump all your cold air out. FYI - the front door opening fridges, though convenient, are a terrible waste of electricity and cooling capacity. Lastly, arrange your fridge/freezer so that you have easy access to the most used things and always put it back in the same place. THat minimizes the shuffling around in the fridge (especially with those like me who have kids).

Hope all this helps.

Brian

Brian--

WHAT A GREAT POST, GOOD JOB! Yes solar is expensive although quickly becoming more affordable. It was doing GREAT before the GREAT ONE imposed a tariff on China which I do not agree with when we are in a world economy but what do I know.

Today one can purchase a polycrystalline 140 watt panel for \$160 delivered from Amazon where I purchased 2 each. The poly panel had advantages and disadvantages over the monocrystalline which cost more today. If I was purchasing panels for my home roof where surface area was critical, mono would be the way to go.

Even the MPPT controller I purchased for \$80 is a great step in the right direction if it achieves anything close to what one expects in a MPPT controller.

You comments on insulation make sense! I will not go to that extreme because we do not live on our boat which spends most of its life tied to a finger pier. How can one not applaud the concept of using a vacuum storage container for coffee. Because I have two battery concepts, one for 12vdc power and another for 24vdc power I will need to run our generator in the mornings for coffee and charging the 24vdc bank. It is used to power my Maxwell HWC2200 windlass along with a Freedom inverter which provides power for a CFL lamp along with our microwave. Our fridge which is indispensable gets powered from a 1kw Xantrex pure sinewave inverter energized from a 12vdc bank.

My newly purchased panels should remove most of the power bite our batteries currently suffer. If I need to increase our capacity, I will at that time purchase another panel.

HEY! I cannot leave this post without commenting on your pictures! Another great job. There will be many who read this thread who will gain insight and knowledge from your post.

Foggy

EDIT: I installed a hard top which is about 10'X9'over my rear deck. I expect to have no problems mounting my collectors.

Last edited by foggysail; 07-16-2012 at 02:44 PM.
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