Installing a simple solar system to charge a one-battery ?

[MitchM]

I am moving marinas and my new marina has NO shorepower . I need to charge one battery for engine start on a small yanmar 10 HP. I am contemplating installing a solar charging system to keep my one engine - start battery charged sufficiently. I am also purchasing a new engine-start battery, and am contemplating installing a " dual purpose AGM to serve both engine - start and a simple house system that currently runs only the bilge pump. we only day-sail and are never out past dusk. ) our old faithful flooded cell lasted 5 years from Interstate, and has finally gone past the point of being equalized back to life. ) .

has anyone done such a simple one-battery solar install ? any thoughts on your system and its components are much appreciated.

 

[dlochner]

A solar system consists of 3 basic elements, the PV panel, a controller, and a battery, along with a few switches and fuses.

The 10 hp diesel does not need a starting battery, a good deep cycle marine battery will work well. I used to start my 30 hp diesel with a Group 24 Deep cycle battery with no trouble.

Simple should not mean going cheap on the components. A Victron MMPT controller with BlueTooth will run around $100, worth every penny. Even in your situation, with minimal electrical demand using the largest battery that will fit, a Group 31 or 27 will be worth the extra money. It will give you more back up power for the bilge pump and and any other devices you might add, like cell phone charging or such. A panel that is equal to the 10% of the size of the battery will be plenty adequate. Unfortunately batteries are rated in amp hours and panels in watts, so a little math is needed. An 80 ah battery (~Group 27) can be represented as 960 watt hours, thus a 100 watt panel would be adequate.

In reality, a panel can be expected to produce on average 3 times the nominal wattage per day. A 100 watt panel would produce about 300 watt hours (25 ah) per day, some days more, some less. You'll have more than enough power. At minimum a 50watt panel might suffice, but no one ever complained about having too much electrical power on a boat.

 

[LakeOntario270]

I had a similar problem. I purchased a 30 watt panel from Amazon that came with a controller. The controller is connected to the battery through a 5 amp fuse. The panel sits on the cockpit seat when I leave the boat and is stored when I take the boat out.

 

[higgs]

My boat has such and arrangement that it came with. The outboard is not electric start so the the solar panel keeps the batter charged enough to run the chart plotter and charge the handheld VHF. It is the size of a typical tablet and seems to do the job.

 

[MitchM]

excellent ideas, thank you all. I have been running AGM s as house batteries in my custom chevy van and getting a good 4 years out of them . a dual purpose group 27 as the only boat battery might do just fine. the Renogy AGM and Interstate flooded cells both get good reviews. but the renogy gives more amps per dollar.
.

 

[jssailem]

I like your thinking.

I am playing with a 50watt panel by GrapeSolar.


A controller from Victron.

And a wiring kit.

About $130 all in. If the test bed works it is easy to scale up

 

[Project_Mayhem]

I have a 100w Renogy panel with two very basic PWM MorningStar controllers. Batteries are always topped off. If I were to do it again, I'd probably go with a 50w. Much easier to mount. Being able to see the state of charge would be nice. Spend money on a decent controller, even if it's PWM and it'll cost you less by saving your batteries

 

[Plumbean]

I have a 50W panel that is now almost 20 years old that keeps 4 Group 31 AGMs topped off on my mooring. When I replace it I likely will go for 100W just so I can leave the fridge on, but if all you are feeding is one battery I would think 50W is fine.