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Old 21-10-2015, 13:28   #31
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Re: So many solar options. Is there a standard?

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Originally Posted by Serapium View Post
Actually, when it's all said and done 2000 watts isn't going to be NEARLY enough. Large fridge and freezer, big watermaker, six people, big flat-screen, four laptops getting frequent use in video and audio production, electric stove top, espresso machine, ice maker, electric skateboards, etc etc.

The biggie though, is ditching fossil fuel entirely and repowering all electric. Power hungry electric inboard and pull the diesel entirely, plus an electric outboard for the dinghy.

I haven't done the full power budget yet for the end vision, but I'm guessing we'll end up north of 5000 watts of generation capacity between solar, wind, and towed array. Probably have something like a 4000AH battery bank as well.

If you're interested (or wouldn't mind giving some advice) I wrote a post about it on our blog.
Sure, I'd love to read your blog!

I'm no expert on electric propulsion, but I did save a few links to interesting websites that seem to have a lot of good info and motors.

One thing I think is worth exploring is using LiFePo4 batteries, for their weight and size savings over lead acid. They're also more efficient than lead acid, which are generally assumed to be 85% efficient. There's also Peukert's Law to take into account with lead acid, it doesn't affect lithium batteries.
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Old 21-10-2015, 13:52   #32
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Re: So many solar options. Is there a standard?

Thanks, I'd appreciate any suggestions (including the links you saved). I started from close to zero knowledge and am kinda making it up as I go along. Without resources like this forum and helpful folks like you the curve would be much much steeper! Here's a link to the first of a two-part post about my design so far.
DIY: The Quest to Go Green on a Sailboat – aka – WTF Is a Hybrid Solar Electric Thermosiphon? | Oh Sail Yes!
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Old 21-10-2015, 19:38   #33
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Re: So many solar options. Is there a standard?

Hi, I totally agree that you should NEVER rely on the Chinese controllers. I went through 2 in a 3 month span and I will NEVER do that again...Being on a budget can be difficult but there are ways to get around things. I went with the Morningside 30 A controller for my 2 150W panels....for now...
Good luck and remember these guys on here know their stuff...
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Old 21-10-2015, 19:54   #34
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Re: So many solar options. Is there a standard?

The Morningside controller is a cheap Chinese knockoff of the well known Morningstar brand.




Just Kidding!
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Old 21-10-2015, 20:40   #35
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Re: So many solar options. Is there a standard?

Quote:
Originally Posted by Serapium View Post
Actually, when it's all said and done 2000 watts isn't going to be NEARLY enough. Large fridge and freezer, big watermaker, six people, big flat-screen, four laptops getting frequent use in video and audio production, electric stove top, espresso machine, ice maker, electric skateboards, etc etc.

The biggie though, is ditching fossil fuel entirely and repowering all electric. Power hungry electric inboard and pull the diesel entirely, plus an electric outboard for the dinghy.

I haven't done the full power budget yet for the end vision, but I'm guessing we'll end up north of 5000 watts of generation capacity between solar, wind, and towed array. Probably have something like a 4000AH battery bank as well.

If you're interested (or wouldn't mind giving some advice) I wrote a post about it on our blog.
I suggest you read this post..
Solar powered boat

This fellow has paved the way for anyone wanting to electric propulsion. Although its certainly possible, its definitely not easy or cheap. Also definitely not as fast or near the range. My hats off if you do take on such a project, I hope your wallet can take the hit.

Something to look into is the Tesla powerwall. Might be a great solution if you have the room and layout in the boat.

P.S. Towed power generation would be useless in an electric boat. It would produce less power than the drag its causing (unless in a current).
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Old 21-10-2015, 22:57   #36
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Re: So many solar options. Is there a standard?

If you are talking electric engine you are also talking high voltage, which means a ton o batteries. Are you going to remove the mast and all that rigging to support the weight of so much battery power?

How much load can a Norman tri handle and still be an efficient boat?

I'm not knocking your idea... we have a friend that has an cat with an electric engine and they gush about it. But he also has a diesel genny, without which he only has a range of 30 miles or so iirc.
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Old 22-10-2015, 08:11   #37
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Re: So many solar options. Is there a standard?

travellerw, thanks for the link. I'll see what I can grok out of it. I am eagerly awaiting the Tesla wall or some derivative thereof. That's part of the reason that we're putting off the electric repower for the time being. I'm hearing all kinds of interesting things about new developments in battery technology. In the very least, for weight considerations we'll have to go lithium at this point. I'm hoping that by the time we get to the repower there may be an even better option available. Maybe even the salt water powered battery

Amazing 12V Saltwater Generator

Low-cost saltwater battery wins $500,000 award

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Old 22-10-2015, 08:20   #38
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Re: So many solar options. Is there a standard?

zboss, by the time we remove the diesel and transmission we'll have shedded 1,200 pounds (it's a big Perkins 4.236). That gives us a lot of extra battery carrying capacity. I've actually looked high and low for the carrying capacity of a 46' Cross Trimaran and haven't been able to locate hard numbers (I even have the original plans and it's not specified there.)

That said, we're not out to win any races or anything. I don't want to stress the structure but we'd have to add an awful lot of weight before we got to that point. A friend who owns a 46 Cross says he carries an absurd amount of stuff and that he's probably overweight... but that they've also been cruising like that for 18 years with no issues.
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Old 22-10-2015, 08:43   #39
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Re: So many solar options. Is there a standard?

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travellerw, thanks for the link. I'll see what I can grok out of it. I am eagerly awaiting the Tesla wall or some derivative thereof. That's part of the reason that we're putting off the electric repower for the time being. I'm hearing all kinds of interesting things about new developments in battery technology. In the very least, for weight considerations we'll have to go lithium at this point. I'm hoping that by the time we get to the repower there may be an even better option available. Maybe even the salt water powered battery
Just make sure you do the math and understand the numbers before you start. This is where many electric conversions go off the rails. They expect the same range and performance and diesel and are dissappointed when they can't get it. They usually discover this after they have dumped 1000s into the effort!

Even with a battery that is an order of magnitude better than a lithium battery, it still wouldn't even have 1/4 the range as a diesel powered boat (equal weight of batteries to diesel). The energy density numbers don't lie. The energy density of diesel is 48 MJ/kg, the energy density of lithium batteries is 0.360.875 MJ/kg. So it would take a 50 times increase in current battery technology to store the same energy as diesel for the same weight. This doesn't factor the size as some new technologies are lighter, but dimensionally bigger (e.g. lithium air batteries). Of course, some of this is offset by the weight of the engine being removed, but its really not that much. Personally I know of no announcement that would put a battery with 50 times the energy density in the hands of consumers in the new 10-15 years.

Finally you have to factor in charge time. With a diesel boat, you can fire up the diesel anytime to get moving. With a solar boat, it takes time to charge no matter the battery technology. Something to think about if you are caught with a few days of cloud and a storm is coming. Of course you could always sail out of the way... Maybe....
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Old 22-10-2015, 10:01   #40
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Re: So many solar options. Is there a standard?

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Originally Posted by Serapium View Post
zboss, by the time we remove the diesel and transmission we'll have shedded 1,200 pounds (it's a big Perkins 4.236). That gives us a lot of extra battery carrying capacity. I've actually looked high and low for the carrying capacity of a 46' Cross Trimaran and haven't been able to locate hard numbers (I even have the original plans and it's not specified there.)

That said, we're not out to win any races or anything. I don't want to stress the structure but we'd have to add an awful lot of weight before we got to that point. A friend who owns a 46 Cross says he carries an absurd amount of stuff and that he's probably overweight... but that they've also been cruising like that for 18 years with no issues.
In talks with most folks that have already installed electric propulsion its really a wash in terms of weight. Plus you need to either carry a ton more batteries or a genny. Which makes it even heavier.

Pound for pound, a diesel engine packs more power than solar and batteries will for a long while.

No expert here - but I did some research previously...

I think most electric engines require a much higher voltage (say 108 volts). So at 2000 watts of solar you are only returning about 100 amps a day to the batteries.

The elco 7000 uses about 29,000 watts in continuous operation, so about 700,000 watts for 24 hours of motoring, or 6480 Ah. I know that sounds like a lot - please someone check my math.

I know my friend can go up to 2 or 3 days by going real slow, around 2 knots.
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Old 22-10-2015, 10:03   #41
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Re: So many solar options. Is there a standard?

traveller, if and when the time comes I'll be plumbing all kinds of resources to assist in the design prior to actually spending a penny on the conversion. I've done enough of the preliminary research that I'm reasonably confident it can be achieved on our particular boat. I think it would be difficult to accomplish on a monohull.

The ultimate goal is to be the first to circumnavigate on board a family-friendly cruiser with ice cream and air conditioning, all without a drop of fossil fuels. I think the tech is almost there.
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Old 22-10-2015, 10:38   #42
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Re: So many solar options. Is there a standard?

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traveller, if and when the time comes I'll be plumbing all kinds of resources to assist in the design prior to actually spending a penny on the conversion. I've done enough of the preliminary research that I'm reasonably confident it can be achieved on our particular boat. I think it would be difficult to accomplish on a monohull.

The ultimate goal is to be the first to circumnavigate on board a family-friendly cruiser with ice cream and air conditioning, all without a drop of fossil fuels. I think the tech is almost there.
Good on ya.. IMHO you won't be able to acheive that (maybe ice cream, but not AC). I really hope you do though...
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Old 22-10-2015, 12:56   #43
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Re: So many solar options. Is there a standard?

traveller, I'm hoping I can get Elon Musk to chip in a penny or three
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Old 22-10-2015, 15:24   #44
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Re: So many solar options. Is there a standard?

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No expert here - but I did some research previously...

I think most electric engines require a much higher voltage (say 108 volts). So at 2000 watts of solar you are only returning about 100 amps Amp hours a day to the batteries.

The elco 7000 uses about 29,000 watts in continuous operation, so about 700,000 watts Watt hours for 24 hours of motoring, or 6480 Ah. I know that sounds like a lot - please someone check my math.
The math is fine, but: Amps v Amp hours v Amps/Hr
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Old 26-10-2015, 22:01   #45
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Re: So many solar options. Is there a standard?

I'm feeling somewhat confused and overwelmed at this moment considering I will be refitting my new to me boat with solar sometime early next year. I currently have a 5k genny, (2) 6000 btu, 110v AC units, 170watts of solar, and 460Ah @12v battery bank with basic instruments and a currently non functioning refridgerator. My plan is to add 230Ah's to the bank, around 500watts more of solar, a fridge/freezer (7.0cf), microwave, coffee maker, tv, and various small electronic's ect... Given this change/usage what would be the best option/s for an inverter/charger/solar chargers, when making such a change to the system? and usage of the system?
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