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Discussion Starter #1
Looking for good solar panels. Recommendations? :)

It is for a Bristol 24. It has space on the hatch, transom outboard well, and forward hatch.

Energy Plan
- Two Batteries: 120 amp hrs (total for both batteries)
1. Tiller Pilot (TP22)
2. Depth Sounder
3. Knot Meter
4. iPad
5. Garmin Glo (Blue tooth GPS feed to ipad)
6. Radio w/AIS (Standard Horizon GX 2150)
7. Navigation lights
8. Interior LED's

I currently have one portable, foldable 25 watt panel.
 

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What region do you sail in, what times of year do you sail, and how often do you want to plug into shore power?

A 50w panel with a good controller (like the Genasun MPPT) would probably be more than enough.
 

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Discussion Starter #3
SF Bay Area. Want it to be offshore capable. Say SF to Hawaii. Will look up Genasun MPPT. Any recommendations on the 50W panel brand and vendor?
 

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Haven't bought the batteries yet. Thought I would throw in some specifications or it would be pretty vague question. Am leaning towards two 27 batteries which are 90A each. I am guessing that they will take on and release charge when going from 80 to 50% and then charged back up to 80.

Still interested in a manufacturer/vendor for the panels. :)
 

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With solar they will charge past 80%. 100% if enough sun with little DC use.

Lots of good brands of panels. I would avoid E Bay and buy from a reputable solar retailer in your area.
 

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Discussion Starter #7
I have heard that some retailers can be as little as $1/watt. Also, wondering about the other specs: weight/height etc. Are the ones for marine use different?
 

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There is no specific marine solar panel really. They are all designed and built to withstand the elements.

Buying at $1 a watt leads you to the bottom of the barrel in quality in most cases. $2 to $3 a watt is more normal I think, maybe $4 a watt for flexible panels like those from Go Power.

The other issue is panel size. The price per watt drops as the panel gets larger but you probably want a small panel - somewhere under 100 watts.
 

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I've had Kyocera panels on my boat for 15 years. Still putting out full power. Tough frame for mounting. Good cable grommets that don't leak. Maybe a bit more expensive,but worth it for the long term.
 

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It is not so much the size of your batteries... it is your pattern of using the boat. How many amp-hours are you consuming between charges?

First, I am assuming you stow the panels while underway in a smaller boat... they'd be in the way underfoot.

If you're on a 5-day cruise, sailing hard every day with instruments, VHF, TP22, etc., then spending the evenings at anchor listening to tunes and using lights... then you'll have lots of amp-hours to recoup once you do place the panels in sunlight service.

If your use is more of weekend use, maybe two daysails surrounding one overnight evening at anchor, you have much less to recoup.

Last, when you do charge via panel, how long before you're using the boat again? If the boat will be idle and charging for days, a smaller panel should suffice. If you'll be right back out in a day, a larger panel is called for.

For what it is worth, on my 28-footer with similar equipment to yours, my weekend-use pattern is easily-supported by one Group 27 90AH deep cycle battery recharged during the work week with a 30 watt panel ($65 on eBay). My battery very rarely gets below 12.55 volts... and after a charge typically reads in the low 12.7s.
 

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Discussion Starter #15
The plan is to cross from SF to Hawaii some day. That is about 20 days of solar only power for the devices mentioned. So planning accordingly.
 

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I've had Kyocera panels on my boat for 15 years. Still putting out full power. Tough frame for mounting. Good cable grommets that don't leak. Maybe a bit more expensive,but worth it for the long term.
They aren't make small panels suitable for small boats anymore. Their smallest panel is 140W and 60" by 26". I don't know where you would fit that on a Bristol 24 without shading.

I am using a cheap Chinese panel on my boat. I'd have preferred to buy something higher quality (or at least from a brand that I've heard of), but quality rigid small panels seems to be a very limited market these days.
 

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I have been using solarblvd.com for several projects and have been happy

Look into 2 6v 115/120Ah batteries (golf cart) for your 12v needs also, I would rather have the reserve power there(that will give you 120Ah total @ 12v)

size will be an issue on a boat, unless you can tilt them to the sun you may only get 3 or 4 hrs of decent sun per day( if that much with shadows and sails etc)

So your 100wt panel may only be putting out 8 or 9amps per day, thats not much

you may need to look at several 40/50/60 watt panels for their size and just tie them all together at the controller or daisy chain them
 

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Good solar panels: Most are well-behaved but obedience training usually isn't expensive if they need it.(G)

Two ways to go, the expensive brand name with a specific "marine use" warranty. Or, generic Chinese product with the expectation that it will not hold up as well but is cheap enough to replace when it fails, assuming that isn't a critical time. Like halfway to Hawaii.

Congress just raised a 30%(?) tariff on the panels the Chinese have been dumping on the US market, so expect prices to go way up real soon.
 

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Look into 2 6v 115/120Ah batteries (golf cart) for your 12v needs also, I would rather have the reserve power there(that will give you 120Ah total @ 12v)

size will be an issue on a boat, unless you can tilt them to the sun you may only get 3 or 4 hrs of decent sun per day( if that much with shadows and sails etc)

So your 100wt panel may only be putting out 8 or 9amps per day, thats not much

you may need to look at several 40/50/60 watt panels for their size and just tie them all together at the controller or daisy chain them
Golf cart batteries are 220 - 240 AH so 2 will give you 220 - 240 AH @ 12 volts.

A 100 watt panel is rated at about 5.6 amps. With a good controller (MPPT) that can get an output of about 7 amps at charging voltage. On a sunny day without panel shading you can get about 35 AH into the batteries from such a panel.

If you are only getting 8 or 9 AH per day something is wrong.
 
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