Wondering why more power boats aren't using solar power to recharge house batteries?

[MV Wanderlust]

Hoping some of you engineering types can explain to us why more power boats aren't taking advantage of solar panels to recharge their house batteries.

Been looking at some mid-80s Chris-craft Catalinas. Most seem to be running a single group 27 house battery. They typically have a full size, 110v house-style refrigerator. Not 12v/110v dual voltage, just straight 110v. That means the refrigerator would only be running when connected to shore power or the generator is running or on an inverter.

Did some research to figure out how many amps a typical full size 'frig would draw per hour. Assuming it only runs about 20 minutes out of each hour and it's running off of an inverter connected to a typical group 27 battery, the battery will only last about three hours.

Looking around on the internet, I found several kits designed for marine or RV use that include solar panels, inverters, and battery chargers similar to this example. It outputs 320W/17.7A, which sounds like plenty to keep the battery charged so that the inverter can supply juice to whatever needs it. If so, the generator wouldn't be needed until evening.

But none of the example boats we've seen online have solar panels. Seems like a no-brainer. Any idea why more power boaters aren't using solar?

Thanks,

John

[StuM]

Their engines generally have large alternators that provide power when motoring for house loads and to charge the batteries.

But I agree with you - many power boats could easily fit a decent solar array somewhere to avoid running the generator. I wish they would do it to stop the fumes and noise pollution in anchorages.



(Oh and it's not "Amp they would draw per hour" - it's Amp hours per hour).

[valhalla360]

Mostly because they don't need it.
- Very few of these type of boats anchor out for long periods.
- They have two big engines that run every time they go out and they each have big alternators charging the batteries.
- Many have generators that will run anyway to run the air/con. Enough power to run the fridge is rounding error.
- They typically spend much of their time in marinas and shore power provides all the electricity they need.


So what advantages would you see for adding solar panels?

[jimbunyard]

Inertia? (or maybe it's ..... $2,703.99 for 320 watts?)

[pickpaul]

Also it doesn't seem like many stinkpotters care about their carbon footprint or they wouldn't have one so that motivation is missing too, but basically long running engines with big alternators and generators.

Sent from my SM-G925T using Cruisers Sailing Forum mobile app

[savoir]

The main reason is that a solar array can't keep up with A/C. Some of the boats on my dock run their A/C and fridge whether the owner is aboard or not.
Different mindset.

[landsend]

All of the above

[sailorboy1]

Originally Posted by pickpaul

Also it doesn't seem like many stinkpotters care about their carbon footprint or they wouldn't have one so that motivation is missing too

that was ridiculous and unneeded insulting

I see larger powerboats with solar panels around. They are the ones that seem to stay on moorings or at anchor for a while and which don't motor from place to place as often.

[wayne.b]

Originally Posted by sailorboy1

that was ridiculous and unneeded insulting

I see larger powerboats with solar panels around. They are the ones that seem to stay on moorings or at anchor for a while and which don't motor from place to place as often.

===

Yes. We have 800 watts of flexible solar panels mounted on top of the fly bridge enclosure. On sunny days they will just about keep up with electrical demand. We still need to run the generator twice a day but not nearly as much as before. It will pay for itself in a couple of years plus the intangible benefit of fewer generator hours. Many/most power boats spend much of their time in marinas however and are connected to shore power almost every night.

Designing and installing an unobtrusive mounting system was a non-trivial effort. I'm thinking of getting a design patent for it.

[LooseGoose]

This setup of removable flexible panels works great at longer stay cruising anchorages....cuts gen run time by 2/3. Made by Unisolar.



https://onedrive.live.com/?cid=4B043...%21256&o=OneUp

[MV Wanderlust]

Thanks, LooseGoose but those links are apparently locked. Unable to access. Will look up unisolar online.

[Steadman Uhlich]

Originally Posted by wayne.b

===

Yes. We have 800 watts of flexible solar panels mounted on top of the fly bridge enclosure. On sunny days they will just about keep up with electrical demand. We still need to run the generator twice a day but not nearly as much as before. It will pay for itself in a couple of years plus the intangible benefit of fewer generator hours. Many/most power boats spend much of their time in marinas however and are connected to shore power almost every night.

Designing and installing an unobtrusive mounting system was a non-trivial effort. I'm thinking of getting a design patent for it.

Sounds interesting to me.
Please post some photos so we can see the solar panels on your trawler.

[Capt_Flrp]

I am much less surprised by the lack of solar as I am the idea of having a single group 27 house battery. With all of the extra charging amps available when the engines run, a fairly large house battery bank could keep the world turning for a day, two, or three. A small generator every second or third day to top of batteries when hibernating in some secluded gunk hole?

[Shrew]

More and larger systems. Many have electric stoves and ovens. Large Fridges and Freezers. You start to need a LOT of panels to make a decent dent in the draw. There is a lot of start-up cost where the ROI is many years as compared to running the generator for a few hours a day. Running hte Genny for 3-5 hours burns a few gallons. It takes a long time to break even with an expensive solar array. For those that only weekend and do a weeks vacation this makes no sense.

Also, bang along 18 - 23 kts and the mounting options become more limited than where you can mount panels on a sailboat.

There is no need to vilafy power boaters.

[LooseGoose]

Here's a new link to photos of a flexible installation on a Bimini top. I hope this one works better for you. Am also surprised at the small battery.....4 Golf Cart 6 volt batteries in parallel will give you 440 AH at 12 volts, about 180 useable AH between recharge cycles.

https://www.flickr.com/photos/organi...57667305514144