Going Solar

So after debating what to do about my issues replacing (charging) 200amps into a 440 amp 24 volt house inverter bank, I decided to go solar as a long term sustainable, environmental and economical solution.

Today I picked up 1000 watts of panels for the 24 v bank and 200 watt panel for the 12 v house bank for led lights, heads etc.

In total I should get my 200amps at 24 volts into the inverter bank and close to zero need for the gensets other than charging hot water, running big 240v davit crane etc.

I am mounting the panels straight on top of Bimini canvas. I reinforced the frame slightly but it is 1inch diameter stainless steel and very strong. I can hold my body weight of the 100kg off it. So spreading the 6 panels over the 4m wide and 3m long top should be no issue at all. All up there is 90kg of panels.

they are wired in parallel with Anderson connections to a 40amp plasmatronics regulator with fuse on positive cable to the inverter bank. The connections of cable from panels means I do not need a junction box up there or out in elements at all.

The panels are attached to the Bimini tubes via four saddle mounts per panel. They will not move.

should hopefully get the panels up there tomorrow then am waiting on my friend who ordered all the parts through his electrical business. Should be done in a week once parts arrive.

This is a job I intend on only doing once so trying to get it right. My last boat had 540watts directly mounted to the Bimini frame and had no issues at all.

shall post a few pics as I go.

I am in the throes of deciding how to "solarize" my boat. Please advise as you progress. Chinese panels?

Bo
For background, I have 1820W of panels and a 1284AH 12V bank. I have never seen more than 90A going into it from the panels.

There are a number of factors that reduce theoretical output from panels, key amongst them on boats is panel orientation (usually near horizontal) and shading from antennas and the like. Given you will be charging your inverter bank at around 28V, your 1000W can theoretically deliver 35A at that voltage. In practice it will likely top out around 25A. This seems to fit with your 40A regulator.

I must be missing something. I can't see how you can get 200A from 1000W of panels at 24V. Your panels might cover much of your daytime consumption, but at night and when the sun is low in the sky you will be drawing down the bank and needing quite a bit of generator time. I think you will need some shore power or generator time during the day as well.

Edit: Just realized you probably mean 200AH into your bank during daylight hours, not 200A charge rate. But still, my guess is you wont see more than 160AH per day into your bank.

My rule of thumb is that a 100 watt, horizontally mounted panel will deliver 33 amp hours to a 12 V battery on a sunny day. Half of that for a 24 V battery.

So 160 amp hours makes sense, but on a sunny day.

David

djmarchand said:

My rule of thumb is that a 100 watt, horizontally mounted panel will deliver 33 amp hours to a 12 V battery on a sunny day. Half of that for a 24 V battery.

So 160 amp hours makes sense, but on a sunny day.

David

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I am consistently getting 80 amp-hrs/day from a 150 watt panel flush mounted to the bridge canvas.

fryedaze said:

I am consistently getting 80 amp-hrs/day from a 150 watt panel flush mounted to the bridge canvas.

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Dave, did you install your replacement panels?

It's not possible to get 80 amp/hours per day from 150 watts. What am I missing?

time will tell what I get out of these panels. At the moment with no panels I get zero amps into my batteries...so will be a good solution to minimise genset use. I was having to run genset 6 hours a day. I use about 200amp hours from the 440 amp 24 volt bank. If I can get genset run time to an hour a day for when we need to use it anyway that will be perfect. Obviously the engine needs to be run or it too will die a slow death...
Today I put all 6 x 200 watt panels up. Wiring will happen next week.

I think I will get between 160 and 180 amp hurs a day. Shall wait and see.

The problem with solar is although it does make some charge at dawn , it takes the sun being high to make much juice. 4-6 hours per day.

14 hours of daylight is not 14 hours at a good charge rate.

Solar quality is dependent on location. Here in Queensland Australia, we have some of the best sunny weather you could hope for.

I do not see any "problems" with solar. All our calculations are not even considering the amps we get from 6am to 9 am or from 4 to 6pm in Summer. I am confident of getting what I need and the economics are undeniably in favor of solar over genset use.

FlyWright said:

Dave, did you install your replacement panels?

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No, I have two failed panels. Only one panel is working. The panel supplies is working to send me replacements. There are issues with China trade restrictions that are preventing shipment of the panel. He says he thinks it will be resolve soon. If not I get a refund.

Xsbank said:

It's not possible to get 80 amp/hours per day from 150 watts. What am I missing?

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We are in Canada and getting daylight from 6AM to 9PM. My Morningstar charge controller has a data logger. It routinely records 80 amp-hrs for a 24 hour period. It has hourly readings. I will try to get them and post. I have seen peak wattage output of 138watts from the one panel.

fryedaze said:

We are in Canada and getting daylight from 6AM to 9PM. My Morningstar charge controller has a data logger. It routinely records 80 amp-hrs for a 24 hour period. It has hourly readings. I will try to get them and post. I have seen peak wattage output of 138watts from the one panel.

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That's astonishingly good! I'm guessing it's from a rigid panel, yes?
I fitted a brand new 150w semi flexible panel at the start of this season, hooked up to a Victron MPPT controller and 330 Ah bank at 12v.

The best I've seen is 6 amps, but it was only giving 5.5amps in early July in the UK in full sunshine just after noon.
I worked it out and I was getting about 82 watts. Very disappointing.
I still don't know why. Everything was OK - clean panel, no shade, etc etc.

As soon as my fridge cut in which consumes 5.5A the charge rate went down to 0.

Have queried it with Victron but they're pointing the finger at the panel.
Problem is, it's difficult to assess in anything but perfect conditions - a few days a year. I still know it ain't right though!

Trundlebug said:

That's astonishingly good! I'm guessing it's from a rigid panel, yes?
I fitted a brand new 150w semi flexible panel at the start of this season, hooked up to a Victron MPPT controller and 330 Ah bank at 12v.

The best I've seen is 6 amps, but it was only giving 5.5amps in early July in the UK in full sunshine just after noon.
I worked it out and I was getting about 82 watts. Very disappointing.
I still don't know why. Everything was OK - clean panel, no shade, etc etc.

As soon as my fridge cut in which consumes 5.5A the charge rate went down to 0.

Have queried it with Victron but they're pointing the finger at the panel.
Problem is, it's difficult to assess in anything but perfect conditions - a few days a year. I still know it ain't right though!

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The panel is semi-flexible. I normally see 9-9.5 amps at midday. The conditions here in Canada have been perfect though. The skies are cloudless and the sun is out for 14-15 hours.

80 amp-hours per day (let's assume 12 hour day) is 960 amps. I think you mean 80 amps/day from a 150 watt panel, or about an average of 7-ish amp-hours per day?

Xsbank said:

80 amp-hours per day (let's assume 12 hour day) is 960 amps. I think you mean 80 amps/day from a 150 watt panel, or about an average of 7-ish amp-hours per day?

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Xsbank: You have it backwards. The original "80 amp hour per day" is what the PP meant in that context.

Amps is the instantaneous rate of energy production analogous to mph. Amp hours is that rate (which will change during the day) times the number of hours that it is produced and is analogous to miles driven. Amp hours is total energy produced (or consumed) and can really only be measured accurately with an integrating battery monitor.

David

"An ampere-hour or amp-hour (SI symbol A·h or A h; also denoted Ah) is a unit of electric charge, equal to the charge transferred by a steady current of one ampere flowing for one hour, or 3600 coulombs." Wiki

So 80 ah is an hourly measure.

I don't mean to be argumentative but I think the poster meant 8-ish ah for a total of 80 for the total time the panels were useful.

Xsbank said:

"An ampere-hour or amp-hour (SI symbol A·h or A h; also denoted Ah) is a unit of electric charge, equal to the charge transferred by a steady current of one ampere flowing for one hour, or 3600 coulombs." Wiki

So 80 ah is an hourly measure.

I don't mean to be argumentative but I think the poster meant 8-ish ah for a total of 80 for the total time the panels were useful.

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Not sure how to get this straight. Maybe if I wrote 80 amp-hrs/day. If the panels could put out constant power it would be 8 amps in 10 hour = 80amp-hrs.


OK, then what is your explanation for an 8D battery with an 220 amp-hr rating? Is it the one hour rating of the battery, or could it be that it is the measure of the battery capacity (like a fuel tank).

BTW, I was a USN submarine electrician. I charged and maintained enormous batteries for a few years.
Dave

Dave
Your panel's performance is excellent. What brand and model is it? How is it mounted - is there an air gap underneath it for cooling?

At my old house I saw outputs close to rated panel capacity, but on my boat I am nowhere near it. Come summer with better sun angles I want to try and improve it.

fryedaze said:

OK, then what is your explanation for an 8D battery with an 220 amp-hr rating? Is it the one hour rating of the battery, or could it be that it is the measure of the battery capacity (like a fuel tank).
Dave

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The standard rating method for amphours from a deep cycle battery to discharge at a rate that completely depletes the batteries after 20 hours. So it is the number of amp hours that can be drawn down over a 20 hour period.

The same principles apply to marine deep cycle batteries that applied to your sub's batteries. They are both lead acid and the discharge rate for a sub's batteries is in the deep cycle range not the starting range. But you probably had more sophisticated charging and monitoring electronics.

David

Insequent said:

Dave
Your panel's performance is excellent. What brand and model is it? How is it mounted - is there an air gap underneath it for cooling?

At my old house I saw outputs close to rated panel capacity, but on my boat I am nowhere near it. Come summer with better sun angles I want to try and improve it.

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They are GLOWTECH panels. The Chinese probably put any name on them you want. They are a China manufacturer. I have them sitting on plexiglass panels on the bridge canvas supports. The panels have industrial Velcro stitched to the edges on top and bottom and the bimin has Velcro/camvas lapels that hold the panels. (see previous post for pictures) I bought them on ebay at $299 a 150 watt panel. BE ADVISED', two of the three panel I bought have failed. I believe the blocking diodes failed. The seller "discountsolar" is working to replace the bad panels. The panels look just like the $900 135 watt panels sold as marine at the boat shows.

Just this week .
I completed the installation Of 825 watts of solar running through an Outback control. My panels are mounted horizontally on top of my Hardtop no shading . as luck would have it here in South Florida it has been cloudy all week with some rain. So far I've been a averaging 2 kilowatts per day. I am waiting for the Sun to shine all day to see what it is capable Of. I am charging 1320 amps of golf cart battery

motion30 said:

Just this week .
I completed the installation Of 825 watts of solar running through an Outback control. My panels are mounted horizontally on top of my Hardtop no shading . as luck would have it here in South Florida it has been cloudy all week with some rain. So far I've been a averaging 2 kilowatts per day. I am waiting for the Sun to shine all day to see what it is capable Of. I am charging 1320 amps of golf cart battery

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Lets us know how they do in good sun. My boat uses about 300 amp-hrs per day. I would need about 3.6 KW per day to be even on consumption. Sounds like you have an awesome setup.

I will let you know.
for anybody that's looking for solar panels in the South Florida area. I bought these from a guy who has 250 and 275 watt Spanish made panels. For $180 each. They are new from a company that is no longer in business. It seemed like he had a garage full of these

It would be interesting to see how many have panels mounted on hard top with subsequent heat increase versus on a Bimini which allows heat dissipation and little reflective heat plus also cooling of air.

There is air gaps under all my panels. Next week I receive the bits to put it all together. I think it might also be interesting to see how many use the solar panel connections that are just the high quality plug style male female joints as opposed to a junction box.

So who has what connections and junction boxes. Even the wiring is critical. I have managed to get the best quality solar panel wiring with all its multi type insulation. Must help out you would think...

what are your thoughts as to set up?

Bohans said:

It would be interesting to see how many have panels mounted on hard top with subsequent heat increase versus on a Bimini which allows heat dissipation and little reflective heat plus also cooling of air.

There is air gaps under all my panels. Next week I receive the bits to put it all together. I think it might also be interesting to see how many use the solar panel connections that are just the high quality plug style male female joints as opposed to a junction box.

So who has what connections and junction boxes. Even the wiring is critical. I have managed to get the best quality solar panel wiring with all its multi type insulation. Must help out you would think...

what are your thoughts as to set up?

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I agree good set up is important, all the details need to be right to get the best out of the system.
But I generally take it as read that people who have installed them have followed the panel maker's & charge controller's recommendations. I certainly have.

I have a 150w panel, with MC4 connectors, 4mm2 wires about 8ft long to charge controller. 6mm2 wires about 7 ft long from controller to battery bank. But only one panel. I wonder if that's where I'm going wrong. Would I have been better fitting 2x 75w panels?

fryedaze said:

Lets us know how they do in good sun. My boat uses about 300 amp-hrs per day. I would need about 3.6 KW per day to be even on consumption. Sounds like you have an awesome setup.

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Today my panels put 3kw into my battery bank. Looks like they peaked out at 667 watts at with peak voltage of 127 going into controller. I am happy with that

Modern panels need just a bright sky to work. My panels are producing 6-8 amps 1 hr after dawn. I produce 3-4kw a day. The controller is also on settling .absorbing etc during the day. I have 4X 235 w panels, Maverick controller. 1150amps house batteries 10xT105's. In the Caribbean. There is lots of cloud in the Caribbean but it's very bright clean air. My Panels are flat on top of the F/bridge bimini.