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Old 25-03-2017, 09:11   #16
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Re: Solar - Trying to keep this simple and not to technical.

sounds like the suggestion of 200watts minimum is a good one with a fridge etc. If for just a the weekends you could get a wind gen and toss the TV over the side.

We have a 50watt panel we let sit on top of the house that we stow below on the odd weekend we are on the boat and a good quality cooler as not to have the hassle of a fridge. With LED lighting and good fans draw is negligible.
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Old 25-03-2017, 09:22   #17
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Re: Solar - Trying to keep this simple and not to technical.

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Originally Posted by JScottHuston View Post
Huge thanks for the input. I was hoping to work with my CFO's (MRS.) budget but my effort may be better spent on waiting.
No need to wait, you just need to find better deals. Currently, Solar Blvd sells brand new 290w panels for $109 (36 cents/watt) and 320w panels for $119 (37 cents/watt).

Just find someplace that is shade free to mount 2 or 3 of those panels (using them for a hard bimini is good, they make nice shade) and hook them up to a nice Victron MPPT controller, either 40 or 60 amp. You'll probably spend more on getting a platform built to mount the panels on.

I've installed a few larger systems (1200w and up) and the feedback was amazing. Suddenly being able to tell the admiral she can fire up the washer and/or the water maker any time during the day makes for a very happy admiral, and the sun even seems to shine brighter.

On my RV I noticed that I was making excess power all day, so I bought a portable ice maker. Now I can't live without it!
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Old 25-03-2017, 10:04   #18
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Re: Solar - Trying to keep this simple and not to technical.

In my opinion, most of the posts here are not helpful.

The situation of the thread starter is to be on shore power all week and he's running out of power on weekends. If he has a 600Ah bank that has been charged by shore power he can use 300Ah of that. If that is not enough it either means that the batteries are not delivering the rated capacity any more or he is using an extreme amount of power.

In the first case, the simple fix is to buy a new battery bank instead of a solar system. In the second case, installing a small 100Wp-panel does help nearly nothing because it is way to small to make a difference when you need 150Ah/day or more.

The first step now should be to find out about the health of the batteries.
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Old 25-03-2017, 10:19   #19
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Re: Solar - Trying to keep this simple and not to technical.

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Originally Posted by JScottHuston View Post
Huge thanks for the input. I was hoping to work with my CFO's (MRS.) budget but my effort may be better spent on waiting.
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Old 25-03-2017, 10:29   #20
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Re: Solar - Trying to keep this simple and not to technical.

Quote:
"Originally Posted by thinwater
Obviously the OP needs a power budget. Add up the amps x hours of everything and check that against the amount the batteries are actually down. I would be shocked if it was lets than 100 AH/day. This can be reduced by not running the fridge and use LED and florescent lighting. With 600 AH in batteries you have 600 x (85%-50%) = 210 AH usable capacity, unless you want to beat the batteries down, so about 2 nights. You will get some engine charging if you motor a lot, but that does not help if you stay in one place. There is the generator, but most of us hate those. Solar is pretty weak when there are clouds. Usually it takes some of everything.

Read-up, get some economical panels and a controller, and the system should pay for itself within ~ 10-20 marina nights. A bargain."



"The op has 300ah nom to work with at the start of each weekend. Or did you miss the part about being on shorepower except on weekends when on the hook"

I disagree with the above statements regarding usable amp hrs. I have a looong history with golf cart batteries. I've installed a dozen golf cart bat banks in my boats and friends boats up and down the gangway. When I was 16 (45 years ago, yikes!) I was in charge of the golf carts at La Canada Country Club. Boy did we abuse those things. We won't speak about the midnight races where we ended up in the water hazard

T105's are designed to be taken almost all the way down to zero, though that will cut their service time in half. However, you can safely take them down by 80% and still get most of the designed service life out of them. So given that your bank is really 675 amps (225 x 3). Your usable is 540 amps if the batteries are in good shape. This is the main advantage of golf bats! If you want to be cautious, stay in the 400- 450 range. Given that you are only talking about 3 days/ nites on weekends, and are otherwise charging on shore power, 200 watts of solar should be more than enough to keep your brews cold & listen to your tunes without having to worry. This is just my .02

After 3 broken axels, 1 cart driven off a cliff, and 2 in the water, I lost that job. But boy we had some fun that summer!
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Old 25-03-2017, 12:00   #21
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Re: Solar - Trying to keep this simple and not to technical.

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Originally Posted by thinwater View Post
With 600 AH in batteries you have 600 x (85%-50%) = 210 AH usable capacity, unless you want to beat the batteries down, so about 2 nights.
Incorrect.

This is the safe, practical usable capacity if charging via engine power, so run time isn't excessive.

With sufficient solar and/or wind, or in combination with engine powered charging, the usable daily range is 50% - 100% (for FLA batteries, as long as the charging energy source is available).
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Old 25-03-2017, 12:08   #22
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Re: Solar - Trying to keep this simple and not to technical.

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Originally Posted by Scot McPherson View Post
The bigger the better, get as big a panel as you can fit on your deck and on top of any houses if you have them. defender.com has lots of choices.
Not always.

In general terms, the bigger, the lower the cost per watt.

But cost / watt isn't everything.

Bigger panels are harder to find unshade mounting locations for.

Bigger panels are more prone to torsion damage.

Bigger panels are harder to handle in a breeze.

Bigger panels are harder to take down and stow away before storms.

So, I think the better answer is, "Size the array to best suit your needs. Size the panels to facilitate mounting and removal."
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Old 25-03-2017, 12:28   #23
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Re: Solar - Trying to keep this simple and not to technical.

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Originally Posted by txg View Post
If you've got 600Ah, are on shore power normally and only need to power light loads for weekend trips, there is absolutely no need for solar.

Your bank should easily last for at least three days without recharging, if this is not the case either your batteries are getting too old or you have something (perhaps unknown) onboard that uses a lot of power.
It's 2017 for pete's sake, no reason to live like the dark ages. My cell phone charger alone is rated at 4 amps, civilized people use kw's of power per day. Might as well get free power from the sun, this way the batteries only have to power the existing loads overnight, not all weekend.
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Old 25-03-2017, 13:36   #24
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Re: Solar - Trying to keep this simple and not to technical.

What am I reading incorrectly? If, as stated, the OP has adequate battery power for a weekend, won't any additional charge as provided by a system within his budget, simply prove a reserve, and therefore be sufficient to solve the "problem?"
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Old 25-03-2017, 13:57   #25
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Re: Solar - Trying to keep this simple and not to technical.

My 1-1/2 cents. I have three 12V (ok 17V) panels that is more then adquate for my boat. I would recommend using two 100 watt 12v panels which in the real world will produce about 45-50 ah's of power in the typical summer day. Buy a renogy 30amp pwm controller for $45. Bear bones but has good set points and works pretty well.

One issue with the large 230-300 watts 24V panels is shipping cost is high. Many times higher then the panel cost as it's truck freight due to physical size of the panel. A 100 wall panel can be delivered by UPS. Plus the big panel MUST have a MPPT controller. My thinking is a PWM controller will give you enough savings to buy a second or third panel compared to a single large 250 watt panel.

my third panel is my floater, its mounted to the life lines with two carabiners one mounted on each side of the panel. I've attached handles on each end and use line to hold the panel at whatever angle I need. It has a long cable that is attached to the controller via a wp plug.
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Old 25-03-2017, 13:59   #26
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Re: Solar - Trying to keep this simple and not to technical.

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Originally Posted by buzzstar View Post
What am I reading incorrectly? If, as stated, the OP has adequate battery power for a weekend, won't any additional charge as provided by a system within his budget, simply prove a reserve, and therefore be sufficient to solve the "problem?"
bingo and if your going to spend the money for a briefcase unit may as well spend an extra 50 and put a pair of 100watt panels and a pwm ontroller so you dont have to worry about power .
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Old 25-03-2017, 14:03   #27
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Re: Solar - Trying to keep this simple and not to technical.

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What am I reading incorrectly? If, as stated, the OP has adequate battery power for a weekend, won't any additional charge as provided by a system within his budget, simply prove a reserve, and therefore be sufficient to solve the "problem?"
Apparently the entire first post.

He never stated, or even implied that he could run his boat off of the batteries the entire weekend. He did state that he wanted to stop running the Honda 2000 at night, which implies that he does run the Honda, including at night.

That's annoying for them, and those moored nearby. Solar power is a huge improvement in lifestyle.
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Old 25-03-2017, 14:12   #28
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Re: Solar - Trying to keep this simple and not to technical.

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Originally Posted by sailorchic34 View Post
My 1-1/2 cents. I have three 12V (ok 17V) panels that is more then adquate for my boat. I would recommend using two 100 watt 12v panels which in the real world will produce about 45-50 ah's of power in the typical summer day. Buy a renogy 30amp pwm controller for $45. Bear bones but has good set points and works pretty well.

One issue with the large 230-300 watts 24V panels is shipping cost is high. Many times higher then the panel cost as it's truck freight due to physical size of the panel. A 100 wall panel can be delivered by UPS. Plus the big panel MUST have a MPPT controller. My thinking is a PWM controller will give you enough savings to buy a second or third panel compared to a single large 250 watt panel.

my third panel is my floater, its mounted to the life lines with two carabiners one mounted on each side of the panel. I've attached handles on each end and use line to hold the panel at whatever angle I need. It has a long cable that is attached to the controller via a wp plug.
That's a non issue in this case. OP lists San Pedro as home port, Solar Blvd is only 50 mi away. Easy drive to go pickup.

For those of you who keep suggesting PWM controllers, you really don't know what you're missing until you get an MPPT. To be clear, if someone gave me a PWM controller, I'd throw it in the trash. I would not even give it to someone else fearing that they might mistakenly waste their time installing it.

I've replaced 4 PWM controllers for customers with MPPT. They saw an immediate 25-35% increase in power out to the batteries with the same panels they thought might be defective. Since space is so scarce on a boat and some people go so far as to buy the most efficient panels to maximize their harvest, why go and waste that much power trying to save a couple of bucks? It makes no sense.
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Old 25-03-2017, 15:05   #29
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Re: Solar - Trying to keep this simple and not to technical.

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T105's are designed to be taken almost all the way down to zero, though that will cut their service time in half. However, you can safely take them down by 80% and still get most of the designed service life out of them.
Absolutely 100% wrong.

Yes they will last longer than cheaper deep-cycles being taken below 50%, but that is the lowest you should usually go to get maximum lifetime.

Regularly going down to 80% doesn't "damage" them, but will cut the total cycles in half or lower.

Higher quality mfg like Rolls/Surrette lose less, about a third their cycles.

In AGM, only Odyssey and Firefly still make those 80% claims, but **every** lead batt will last much longer sticking to 50%.
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Old 25-03-2017, 15:32   #30
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Re: Solar - Trying to keep this simple and not to technical.

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Originally Posted by socaldmax View Post
It's 2017 for pete's sake, no reason to live like the dark ages. My cell phone charger alone is rated at 4 amps, civilized people use kw's of power per day. Might as well get free power from the sun, this way the batteries only have to power the existing loads overnight, not all weekend.
An energy consumption this high obviously has nothing to do with a phone and the 4Amps charge current are only drawn for a short time until the phone battery is back to full. Even the biggest and most modern phones don't have more than 20Wh of batteries and including losses this sums up to about 2Ah from a 12V system for a full recharge.

The first post of this thread states clearly that there are no high-consumption devices like air conditioning or freezers on board the boat. So a 600Ah bank should run the boat for a weekend without any problems. As this is not the case, either the batteries are bad or there is another problem that wastes a lot of energy.
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