Sail Boat Solar power

[vortac]

My boat is on a mooring and use it locally I have a freezer and refrigerator I would like to keep running, between going out on the boat.
I currently have 4-135ah batteries from west marine.
These batteries need to be checked occasionally and add distilled water if needed. New this year 2020
Assuming Lead-acid 50% rating on Amp Hours
After reading and watching Videos.

The Variable how long does the compressor run during a 24 hour period. So How many amps will it draw on average during the same 24 hour period
( I have to get a DC amp meter }
2-12volt compressors drawing 40 watts each estimate 80 watts total Might be as much as 100 combined if both running at the same time. I also am thinking of just running one unit to use less power
Just want to keep the beer cold

Can I get away with a smaller solar array? With my current battery set up. Running both refrigeration units. I have to go down every 36-42 hours to run the Genset or engine on the boat. Can I put a system in that will maintain the batteries during the day? Refrigeration runs on battery at night, And repeat this process till I return the boat. Looking for 4-5 days in between.

Refrigeration ( I am adjusting the number to 36w figuring 1/2 amp over 24 hours or less running amperage ) Maybe based on how many bottles of beer
36w X 24 hours = 864-watt hours ( 80 watts if both compressors run constantly )
With no reserve power figured in, I would only need 2 of the batteries. I have 4 x 135 ah batteries,
WILL this give me the extra I need to stay with a smaller system ???

At these numbers 12volt x 200 ah battery = 2400 watt-hours
2400 watt-hours / 50 % = 1200 watt-hours
1200 watt-hours / 5 hours sun average = 240 watt of Solar
I think I could use 240 watts of solar and a 20 amp charger 9 ( I would go with a larger charger )
Will a larger charge, charge the battery bank faster say a 40 amp charger ???

Current Batteries
135 amp hour X 4 = 540 amp hours
540 amp hours X 12 volts = 6460 watt hours
50% percent usage + 3240 useable watt-hours

You mention Battle Batterys 1200 amp hours ( 5 times cost But might be worth it ) I could go 2-3 batteries
Can they be used on a boat ??

Thanks in advance for thoughts comments and help in design and experience

 

[Craig]

A larger SCC will not necessarily charge your batteries faster but the 20 amp one you have is pretty much maxed out with 240 watts of solar and a 12v battery . If you do not want more panels I would get a 30 amp charger just to have some overhead on those days when the panels reach or excede their max rating. If you want to charge faster you need more solar along with a bigger charge controller.

if your usage numbers are correct 1200 watts is still pretty close to what you need but to me it is still undersized. (I do realize space is probably an issue) But if you could get up to 300 watts of solar I think you could run both coolers without issue.

 

[softdown]

I'm not aware of much flexibility in solar array sizing of sail boats. It is what you can hang from the aft in my experience. I foresee a downsizing to one chest fridge.

May as well cycle the existing batteries until they go. Victron makes a 300 watt inverter that uses very little energy. Got to defend the beer!

Large battery banks with insufficient charging is an expensive disaster.

 

[schmism]

I follow quite a few blue water sail boat youtube channels and there seems to be 2 options.
1) a bunch of small 100w pannels spread around the boat, mounted to sides that you can deploy or squeezed in on cabin roofs. The other option is to put up only 1 or 2 large rear panels on the rear of the boat that also double as a (shade) roof.

You didnt say how big your boat was but a single large panel with a permanent mount on the rear may be a good option. My 345w panels are 1mx2m (almost a full size sheet of 4x8 plywood)

The other choice that most sailboats use is a small wind turbine. Being on the water you get a lot more wind. Typically these take 10+mph to make any real watts but the nice thing is when the storm blows in overnight your making 300w all night.

 

[Craig]

There are also a wide range of flexible panels now available. May be a bit pricey but they seem to be becoming more mainstream. I was looking at some yesterday that can roll up like a trailer awning.

 

[vortac]

Thanks for the input

I thought I could get away with a suitcase set up 120 watts. as a Trickle charger supporting the batteries.

whats would the addition of a 120watt panel add to battery life. How long would it extend the batteries before they go dead

With that 120 watt set up charging, and still having the units running would give me the extra days I needed.

My calculations are base on a minimum of 1200 watt would be with no reserve time.

Found a rheology panel 175 watts 289,00 home depot x 2 = 350 watts
probably need a 40 amp controller.

the boat has a master volt inverter assuming 2000 watt
I also have cristec charger 110 volts that charge the battery when the engine or gen-set run

I saw were some have put on the bimini with grommets. My concerns it acts as another sail

You think that I have a larger battery bank charging would be a problem, going with a 40amp charger no matter the solar watts would be better for my battery bank.

I will be riding these current new batteries out unto the die. probably sooner than later. I have gone down and found the refrigerator off

I would like something to roll out and dump in a locker for now. Probably adapt to a fixed install over the bimini. I do not want to get involved with the fabrication of stainless.
I have seen some boats with panels supported to the safety rails . not sure if I like the look

 

[vortac]

I follow quite a few blue water sail boat youtube channels and there seems to be 2 options.
1) a bunch of small 100w pannels spread around the boat, mounted to sides that you can deploy or squeezed in on cabin roofs. The other option is to put up only 1 or 2 large rear panels on the rear of the boat that also double as a (shade) roof.

You didnt say how big your boat was but a single large panel with a permanent mount on the rear may be a good option. My 345w panels are 1mx2m (almost a full size sheet of 4x8 plywood)

The other choice that most sailboats use is a small wind turbine. Being on the water you get a lot more wind. Typically these take 10+mph to make any real watts but the nice thing is when the storm blows in overnight your making 300w all night.

I just saw an episode a guy from Sweden drilled them into the top of his Beneteau 40 ouch

 

[softdown]

Flex panels are built to flex for installation. Continued flexing will snap the electrical connections and make an odd sail. Last I heard they were also short lived as a rule - but that was a few years ago.

Sailors never seem to like wind gensets on the fore. Noisy for one thing - they always prefer solar panels. In fact some decided to remove the wind genset. I spent quite awhile dreaming of living on the oceans of the world. These folks are solar savy with great vids: https://www.youtube.com/user/briantrautman

 

[vortac]

Flex panels are built to flex for installation. Continued flexing will snap the electrical connections and make an odd sail. Last I heard they were also short lived as a rule - but that was a few years ago.

Sailors never seem to like wind gensets on the fore. Noisy for one thing - they always prefer solar panels. In fact some decided to remove the wind genset. I spent quite awhile dreaming of living on the oceans of the world. These folks are solar savy with great vids: https://www.youtube.com/user/briantrautman

seems to be a lot of people sailing and making videos on you tube making money

 

[softdown]

seems to be a lot of people sailing and making videos on you tube making money

Makes sense. Sailing full time is the dream of money. Those who do it have plenty of spare time and constant expenses - with income from? There were four channels that I watched on a regular basis. The Aussie couple had a mega disaster and scared a number off - they slammed an unknown reef at night and were lucky to survive. It was scary to watch the footage. The girl was understandably horror-struck. To put it lightly.

I quit watching after that. Unsure what happened to the couple. It shook up the online sailing community I think.

Youtube stars make quite a bit. But what percentage make it kind of big? Making good vids is a lot of work.

 

[Getyourbone]

Makes sense. Sailing full time is the dream of money. Those who do it have plenty of spare time and constant expenses - with income from? There were four channels that I watched on a regular basis. The Aussie couple had a mega disaster and scared a number off - they slammed an unknown reef at night and were lucky to survive. It was scary to watch the footage. The girl was understandably horror-struck. To put it lightly.

I quit watching after that. Unsure what happened to the couple. It shook up the online sailing community I think.

Youtube stars make quite a bit. But what percentage make it kind of big? Making good vids is a lot of work.

What YouTube channel hit a reef? You say Aussie and I immediately think Riley and Elayna?

 

[Jdplus33]

I’m on my third cruising sailboat, all off-grid cruising capable. About 10,000 nm but who’s counting?

If your goal is just keep the beer cold, shut off the freezer - dead load for no gain, and freezers by definition use more energy.

Figure your refrig at about 70% cycle-on time. As you pointed out, your existing batteries should handle the load.

I would go as big on the panels as you can (to a point) given space constraints. You might be surprised how nice it is to use your gps and nav lights and radio (radar? huge draw) for night sailing. I’d go 200-300W if you can.

 

[softdown]

What YouTube channel hit a reef? You say Aussie and I immediately think Riley and Elayna?

I don't recall the names. It has been several yeas now.

A lot of people tire of the constant movement after a few years or so. Especially the ladies. I could see doing it part time - maybe 6 months/year.