Solar panels?

rtpassini

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Nov 27, 2008
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I was at a store today and saw different sized panels for boats to charge your battery. Are these any good? I believe they were made by a company called coleman.
 

sschefer

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Nov 13, 2008
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Re: Solar panels?

My brother had one on his 14' with a single deep cycle battery. We were never able to determine if it was doing any good or not. I certainly didn't keep up with the trolling motors thirst for juice and it didn't fully recover the battery even after a week in the sun. This was just a small 12x15 panel. I've heard they are great and they do sell components to keep you from over charging your batteries so I guess if it's sized right it will work.
 

rtpassini

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Re: Solar panels?

there was at least 24x12 and one that was twice that size. the smaller one was 88 bucks.
 

sschefer

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Re: Solar panels?

You could just do the math and see what how much current they produce vs how much you need to charge the size of battery you are using. A standard starting battery would probably charge O.K.

I know that my 100 hp Mariner's 9 amp stator output isn't enough to recover my deep cycle batteries. I have an onboard charger the I have to plug in to get them back to normal.
 

Silvertip

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Sep 22, 2003
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Re: Solar panels?

Look at the numbers on the carton. Then do the math. Any battery charger or solar panel that is rated at 2 amps output or less is considered a battery maintainer -- meaning it's purpose is to keep the battery topped off during storage or periods of non-use. Solar panels are typically rated in WATTS of output at 12 volts. So here's the forumula:

Amps output = Watts/volts (12.6). To keep this simple, a 12 watt panel would deliver only 1 Amp of output current which is a very insignificant charge. If you get my drift, these units are simply battery maintainers and definitely NOT battery chargers. Yes, you can buy a high output solar panel but it will be nearly the size of your boat. I have one mounted in the window of my shed to keep my tractor battery topped off during the winter. That's all it's good for.
 

mthieme

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Oct 6, 2007
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Re: Solar panels?

I use a small .5 amp panel on my stuff.
It maintains the charge.
I've never measured it, but have never had to jump or recharge anything after using solar panels.
I have a growing number of panels on the roof of the house which is used for lighting and backup should the power go out.
 

rtpassini

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Re: Solar panels?

i would get one to run the stereo when fishing. would that do the trick?
 

mthieme

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Re: Solar panels?

You could probably run the average radio off the average battery for a month...not that much draw.
Anything will do.
 

rtpassini

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Re: Solar panels?

You could probably run the average radio off the average battery for a month...not that much draw.
Anything will do.

oh really? hm. my sound system in my car would drain my battery pretty quick. but then again... i had 4000 watts going. lol

i would just have a marine cd player and 2 round speaker. maybe 6x9's if i was feeling zesty.
 

mthieme

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Re: Solar panels?

That's why I tried to qualify my statement with 'average'.
I guess average is relative though. My bad.
Although you never mentioned anything more than a radio before.
Still, a small panel still sounds like the ticket. You can get a 1 amp panel about 10-12" square for $40-50. This will maintain your charge under normal conditions (there I go again!).
If you're looking to charge your battery, we're in a different ballpark now.
My panels are throwing 16.5 amps into 3 deep cycle backup batteries. It can easily take a week to get the batteries 2 volts up this time of year. Two volts can become very important. Summer is less of an issue as the sun is 'stronger' and the days are longer and usually less overcast.
 

rtpassini

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Re: Solar panels?

yeah, i wouldnt do anything crazy. just small speakers and cd player. i would use it just for maintaning the battery. if it ever gets too low, i would slap it on the charger.
 

rtpassini

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Nov 27, 2008
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Re: Solar panels?

awesome. thanks!
now i just need to find a place to mount it. lol
 

mthieme

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Re: Solar panels?

I simply set mine on the doghouse when she's docked.
You're not going to hurt the battery just with the radio on all day.
 

ondarvr

Supreme Mariner
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Apr 6, 2005
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Re: Solar panels?

Save your money, the output from a cheap small unit is insignificant, it will not help you at all. Use the same money and buy a second battery if you really need something.
 

Boatist

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Apr 22, 2002
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Re: Solar panels?

That charger only puts out .39 amps at the best sun angle in the middle of the day. The rest of the day it is even less. Cheap solar panels like that one also can draw power from the battery at night. Good solar panels put out a lot more power and have a diode to prevent it from draining the battery is hours of darkness. Save your money. Even the lowest power cheap car radio requires 10 times more power than that solar panel put out.
Only radio that panel could power would be a pocket AM/FM radio that runs on a small 9 volt battery.
 

tashasdaddy

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Nov 11, 2005
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51,019
Re: Solar panels?

save your money, and just be a large deep cycle battery and charge between uses. the only real use i see for these panels, is a boat that is moored, with no source of power to recharge the battery. many sail boats use them as maintainers.
 

Silvertip

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Sep 22, 2003
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28,771
Re: Solar panels?

I have one of those. .39 amps at 12.6 volts. It is nothing more than a maintainer.
 
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