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It is possible to buy modules that connect directly to the grid, however that might not be able to supply the needed power to your charger. Basically they consist of a "normal" low voltage DC PV with an "advanced" inverter that creates AC based on that, so you would loose something during that, and again in your charger. So it's probably not worth it..
 

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I think a little more explanation of what you have in mind would be in order, because at this point the question really doesn't make much sense.
 

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Discussion Starter #4
In response to denverd0n, I was hoping to plug a solar panel directly into my shore power input during the winter month's in order to prolong the life of my batteries. However, I don't know anything about wiring solar panels, which is why I wanted to use the shore power input, it's also probably why my question doesn't make much sense. Do you have a better idea?
 

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Your panels are wired (either in series or parallel) to a solar charge controller which is wired directly to your batteries. Your shore power is 110v (in the US) and I do not even know what effect (if any) wiring to it would be.

You need to decide the charge controller first. That decision will be based upon the total input of your panels. THen you will know how to wire your panels to the charge controller which will monitor and correctly charge your batteries.

Given the nature of what you are doing, I would suggest a thorough review of marine wiring and especially solar panels before attempting any major battery/boat related activities. I mean this with no dissrepect.

- CD
 

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Solar panels are designed to charge your batteries using low-voltage direct current (DC).

The shore-power plug is designed for high voltage alternating current (AC) power....a totally different thing.

You need to connect the solar panel to your batteries with it's own connector and, if it's larger than a very small panel, you'll need some sort of solar controller to be sure you don't cook your batteries.

Bill
 

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Discussion Starter #7
Yes, it's true, I don't know a thing about marine wiring. In general, what is the most cost efficient way to keep batteries charged while dry docked in the winter?
 

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Why would anyone design a solar panel that way. It doesn't make sense and would increase the cost of the panels incredibly. Solar panels are generally used to charge batteries. As such, they need to output relatively low voltage DC... trying to convert the low-voltage DC output to a high voltage AC output would require fairly sophisticated and inefficient hardware—specifically an inverter. Then to use the electricity on the boat, say to charge the batteries, you'd have to convert it back to DC... incurring even further losses.

The most cost efficient way to keep the batteries charged when dry docked is to take them home and put them on a three-way smart charger about once every two weeks.
 

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Yes, it's true, I don't know a thing about marine wiring. In general, what is the most cost efficient way to keep batteries charged while dry docked in the winter?
Shore power with a good charger. You batts will lose (assuming wet cells) about 5%/month just sitting there.

Off the grid apps require either a generator, wind, or solar. Which is best for you would be impossible to say. My best guess is that you will be stuck with solar if you are off grid. However, they are not awesome up north with your cloudy days.

You may be best off just pulling the batt out periodically and putting her un der a charge and returning it to the boat the next day. The other options, assuming you have no electricity, start getting a lot more expensive.

- CD
 

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Discussion Starter #10
In response to Sailingdog, that's not the most cost efficient way to keep batteries charged if you live in NYC!
 

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Why would anyone design a solar panel that way. It doesn't make sense and would increase the cost of the panels incredibly. Solar panels are generally used to charge batteries. As such, they need to output relatively low voltage DC... trying to convert the low-voltage DC output to a high voltage AC output would require fairly sophisticated and inefficient hardware—specifically an inverter. Then to use the electricity on the boat, say to charge the batteries, you'd have to convert it back to DC... incurring even further losses.

The most cost efficient way to keep the batteries charged when dry docked is to take them home and put them on a three-way smart charger about once every two weeks.
SD,

I think he simply does not know how they work. I would not blame him. When you look at these things on the shelf (West Marine being the worst) it looks like you simply shell out a hundred bucks, throw this little flimsy panel on your bimini, then wa-la: You can power a city. It is the way solar is marketed and the lack of knowledge by those that sell them.

I still stand by what I said that electricity on a boat is a serious deal if you do not know what you are doing.

Voice3 - tell us what you want to do... with battery size, type, and what resources are available and we will try to give you the best information we can.

- CD
 

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Discussion Starter #12
Yes, it's true, I don't know how they work (didn't I write that already).

I just purchased a 31' Sloop, my first sailboat, and I plan on taking it to a marina in the next couple weeks to have it stored for the winter. It has one engine battery and two house batteries, but I don't know the exact size of the batteries.
 

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While I agree that it requires and advanced inverter, a number of companies produce PhotoVoltaic modules for connection directly to the grid. The controllers are rather complicated, but as they're produced in (relatively) high numbers, they're still affordable. Many architects in Europe (and I believe CA) integrate these into new buildings. I agree that it's a bad idea for a boat though :)
 

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Yes, it's true, I don't know how they work (didn't I write that already).

I just purchased a 31' Sloop, my first sailboat, and I plan on taking it to a marina in the next couple weeks to have it stored for the winter. It has one engine battery and two house batteries, but I don't know the exact size of the batteries.
Then you are probably best off just not worrying about the batt (if there is no electricity there) or pulling it out and throwing it in your garage with a cheap little portable charger like you get from Walmart or something.

- CD
 

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Discussion Starter #15
Yeah, I think you're right. I'm just going to leave them be and take my chances in the spring. The broker said something about having gel batteries. Does that make any difference?
 

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If you're going to leave them...make sure they're fully charged to start with.
Yeah, I think you're right. I'm just going to leave them be and take my chances in the spring. The broker said something about having gel batteries. Does that make any difference?
 

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Yes, it's true, I don't know a thing about marine wiring. In general, what is the most cost efficient way to keep batteries charged while dry docked in the winter?
Remove them from the boat, bring them home to your garage and charge them with the use of a charger that is protected and will not overcharge.

FWIW, I leave our batts on board and simply disconect the ground. In the spring I charge for about a week or two before launch. Not sure thats the propper thing to do, but its very easy.
 

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"FWIW, I leave our batts on board and simply disconect the ground. In the spring I charge for about a week or two before launch. Not sure thats the propper thing to do, but its very easy."

Yep, it's easy. But it's a sure way to damage your batteries.

Unless kept at a full state of charge, batteries will sulfate, causing temporary and...later...permanent loss of capacity. There's no way around this conundrum. If you want to maintain full capacity of your batteries, you MUST keep them fully charged.

Flooded batteries have a much higher self-discharge rate than do AGMs and Gels, so they are the ones which need the most care. Also, batteries which are uncharged can FREEZE.

With a new-to-you boat, you don't know what the condition of the batteries really is. I think you have two options:

1. Leave the batteries on the boat over winter. Plan to install new batteries in the spring, and to treat them well. You'll then know what you have and how long to expect them to last...approximately; OR

2. Remove the batteries and keep them charged at home. Maybe you can squeak out a few more months or even years of use.

Up to you... :)

Bill
 

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But it's a sure way to damage your batteries.
I usually get about 3 -4 years out of the cheap West M wet cells.
When I'm done with em I toss em.
 

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Yeah, I think you're right. I'm just going to leave them be and take my chances in the spring. The broker said something about having gel batteries. Does that make any difference?
If you have gells, you will have very little self discharge. In that case, just turn off the batt switch and come back in Spring. Maybe even disconect the terminals?? I do not think I would even go to that much trouble.

- CD
 
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