Designing a Solar system for mini Houseboat

[Hillbilly2]

Hello, I am brand new to this forum and hope that members will be able to help me learn to design, select components, then install Solar panels on my, just purchased, very tiny 28” Landau Pontoon Houseboat. As the boat must be moored, most often, to a buoy with no electrical hook up available, I want to design and install a system that will provide enough, 110v and 12v juice to power it’s old and future Solar driven equipment. As the attached rough diagram reflects, I want to install a number of pieces of electrical power equipment, which will allow me to use the boat on weekends with its bank of house batteries charged when I arrive. I’m looking for guidance on how to design the boat’s complete electrical system, recommendations on the best, most appropriate and size products to purchase, and instruction/hints on how to best install/adjust them into a well functioning, off grid power system. I have tried to estimate the DC and AC power requirements to allow selection of type and size/capacity of the system’s electrical components. I don’t really need a roof Air Conditioner, but want to determine how much it will cost to have that capacity. I saw that Amazon is offering a 1,600W flexible panel kit for $190 which got me thinking about using an air conditioner off-grid. I have also included both an DC/LPG and a small inline A/C hot water heater because I haven’t decided which way to go on that

Please look at the design of my Solar system and tell me what I should change due to my mistakes/lack of understanding of Solar power, and fill in its blanks on component capacities, wire size requirements, and your recommended component brands. Any other advice/guidance you can provide will really be appreciated as I know almost nothing about employing Solar panels.

Feel free to call me, Jim Price (Hillbilly2) at (859) 351-3215 or email me at jimprice1559@gmail.com if you need to connect with me. Thanks for taking the time to look my design over. Jim

 

[Rocketman]

I would remove your actual name, email and phone- if someone wants to discuss with you give those out in a private message.

Just looking at it - you have a good start, but still a ways to go.

First, how much room do you have for solar panels? Measure the space (don’t guess).

Also, I like that you started with Victron equipment- it is great equipment. A bit more expensive- but every good quality and gives you information to help make decisions.

Your electric needs may outpace your available solar. That’s why I would start with filling out how much solar you can fit. Pick a basic 330w-ish panel how many can you fit on the roof,

I full-time in my MotorHome with all Victron equipment (except a diy 544ah 12v battery)
My equipment list is
544ah 12v lithium battery
Multiplus 12/3000
1200w of solar in two arrays
Dc-dc 30a battery charger (charges lithium bank when engine is running).
Generator (diesel) came with rig.
Cooking- propane burners
Baking- convection microwave
Propane water heater
My fridge is a residential fridge 120v.

The 1200w of solar is usually enough solar for our needs, but a bad solar day (heavy clouds) and I need to start the generator.
I can run my RV air conditioners for about an hour, then I need to start the generator or stop because I will run out of power overnight. (It has a MicroAire EZ start on it). Thus I seldom run the air conditioner on the battery.

The fridge power looks very high, is that a residential fridge or an absorbing fridge on electric? My old fridge used 424w on electric 24/7 - way too much. The residential fridge was more than covered by adding 400w of additional solar.

I see an alternative on your drawing… is that the main engine alternator? Is there a high power one for the house bank? Does it have external controls?

Alternators can be a bit tricky. Most RVers put in the Dc-Dc chargers because that’s easy and safe. It can be done, but you need to be very careful. We can discuss later…

Good Luck

 

[Bop]

Avoid flexible panels- they cost more per watt, often the plastic discolours and fades within a few years and their efficiency is low (for mobile applications, go the panels with the highest efficiency possible- more watts in a smaller area, although I usually for house usage I recommend going for the cheapest per watt, that puts the high efficiency panels out of the running- in mobile use, space is limited...)
Measure the space you have available for panels- they are available in a variety of panel sizes (both physical and wattage levels) with confined spaces- it often pays to not go 'the biggest' if it leaves unused spaces, where smaller ones might fit an extra panel in and end up with more total wattage...
(it's a bit of a juggling act depending on the available area and panel dimensions- you may need to 'mix and match' the panels orientation to squeeze as many in as possible)

Some of your usage levels seem a bit off (are they per hour or per day?)
The running lights - are they LED or incandescent?- seems high at 30Wh if per hour but your 'house' lights are using the same???
Same with the fridge (4.8kwh??? my full size '400L household fridge' only uses 1.2-1.4kwh- a day!!! in our Australian heat...)


Same with the TV- my big TV is only using about 80W per hour of use- 800Wh is ten hours of TV a day...

 

[Hillbilly2]

I would remove your actual name, email and phone- if someone wants to discuss with you give those out in a private message.

Just looking at it - you have a good start, but still a ways to go.

First, how much room do you have for solar panels? Measure the space (don’t guess).

Also, I like that you started with Victron equipment- it is great equipment. A bit more expensive- but every good quality and gives you information to help make decisions.

Your electric needs may outpace your available solar. That’s why I would start with filling out how much solar you can fit. Pick a basic 330w-ish panel how many can you fit on the roof,

I full-time in my MotorHome with all Victron equipment (except a diy 544ah 12v battery)
My equipment list is
544ah 12v lithium battery
Multiplus 12/3000
1200w of solar in two arrays
Dc-dc 30a battery charger (charges lithium bank when engine is running).
Generator (diesel) came with rig.
Cooking- propane burners
Baking- convection microwave
Propane water heater
My fridge is a residential fridge 120v.

The 1200w of solar is usually enough solar for our needs, but a bad solar day (heavy clouds) and I need to start the generator.
I can run my RV air conditioners for about an hour, then I need to start the generator or stop because I will run out of power overnight. (It has a MicroAire EZ start on it). Thus I seldom run the air conditioner on the battery.

The fridge power looks very high, is that a residential fridge or an absorbing fridge on electric? My old fridge used 424w on electric 24/7 - way too much. The residential fridge was more than covered by adding 400w of additional solar.

I see an alternative on your drawing… is that the main engine alternator? Is there a high power one for the house bank? Does it have external controls?

Alternators can be a bit tricky. Most RVers put in the Dc-Dc chargers because that’s easy and safe. It can be done, but you need to be very careful. We can discuss later…

Good Luck

The flat roof is large enough to place as many as 12-15 100W panels.
I Like your use of a MicroAire EZ Start. Frig Power, I plan to install a 4.5 CF 120v residential frig. I must have screwed up my Frig Wh as being only 480Wh. My mistake on the drawing. I was using the auto generator on the drawing to reflect that my outboard motor charges the starting battery when running or (switched) house battery.

 

[Rocketman]

100w panels (per watt) are expensive. See what you can find locally in bigger panels - 330 to 350w seem to be the sweet spot right now, but they need to fit your boat well.

If you go with two different panels you will need two different arrays (wires and SCC), that’s really not an issue.

Because you have some larger loads, you may want to consider 48v for the battery and a Multiplus 48/5000 inverter, batteries cost more - Solar charge controllers and wires cost less - you may also need a 48 to 12v converter.

 

[Hillbilly2]

Thanks for all of your replies, however, I am searching for knowledgeable help in filling in the blanks on my solar system design as I don't know enough to size all of the components, the wiring segments, and choose the best brand/style/capacities for all of the components. Questions like; what's the largest solar panel power I can install which will power all my stuff without ever having to plug the boat into a 120v source, etc. If what I am looking for is not possible, can someone recommend a commercial/professional company that I can pay to fill in the blanks in my design? Thanks again for all of your comments and help.

 

[Rocketman]

What is the size of area that you can install solar panels? How many feet/inches by how many feet/inches… is it all flat? Curved? 2-sided?

Once we know how much room you have, we can pick a panel and see how many will fit. That will tell us the max amount of solar you will have on great bright day - not all days are great bright days…

Will it be enough- who knows. By learning step by step you will understand the limits of your system,

 

[Hillbilly2]

Thanks for the question Rocketman. My roof is completely flat and measures 8' wide by 24'Long for 192 SQ FT. The only roof protrusions are a 6"W x 15"L refrigerator vent and a 2" round vent over the bathroom. I don't go up on the roof, so, all of it is Solar Panel available.

 

[Rocketman]

To start I just picked this panel… (no reason other than it’s about the right size).

Bluesun 415W Solar Panels ~ 108 Cell Half-Cut Single-Sided (36 Panel Full Pallet) | Current Connected

Bluesun 415W Solar Panels: Mono Perc Half Cut Technology, Pmax of 415W, and a 21.23% efficiency rating. Experience energy generation at its best.

www.currentconnected.com

That panel is 67.9” x 44.6” x 1.38” inches

You have 96” x 288”.
You can get 2 wide by 4 long
8 panels * 415w = 3320w

By looking at different panels you may find some that will allow more wattage on the roof. Hopefully the two vents are positioned so you don’t lose panels.

Look around locally to find solar panels in the 330w+ range and run their sizes for your roof. You may also want to get the exact measurements of the roof and also figure out if you can overlap in certain directions and by how much.

Now you know you can fit about 3000+ watts on the roof.

With 3000+ watts you can probably run the air conditioner most of the day and still charge (provided it is a bright and sunny day).

Added: when doing all the solar for you House bank - add a 100w (or so) panel to keep the starting battery completely charged. A mppt 75/15 is just right.

 

[Rocketman]

The next question is do you want your battery bank to be 48v or 12v? (Or 24v)

If you have 48v, you will either have a converter 48 to 12v to run the 12v loads or you will have a 12v battery and the 48v will keep it topped off.
You have a lot of 120v stuff with large draws:
Microwave
Water Heater
Air Conditioner
(Coffee maker?, Air Fryer?, InstaPot?)

If you go 12v Multiplus 12/3000 you can only ever run one large item at time.

If you go 48v Multiplus 48/5000 you can run two large items at once. 48v means smaller and fewer Solar Charge Controllers a 250/70 would probably handle the above solar just fine vs needing three 150/100 Charge Controllers at 12v. 12v will also use much thicker copper cables - 4/0 vs 2awg for 48v for the main bus.

 

[Hillbilly2]

Thanks, Just what I need. Please keep going!

 

[Orkeven]

The next question is do you want your battery bank to be 48v or 12v? (Or 24v)

If you have 48v, you will either have a converter 48 to 12v to run the 12v loads or you will have a 12v battery and the 48v will keep it topped off.
You have a lot of 120v stuff with large draws:
Microwave
Water Heater
Air Conditioner
(Coffee maker?, Air Fryer?, InstaPot?)

If you go 12v Multiplus 12/3000 you can only ever run one large item at time.

If you go 48v Multiplus 48/5000 you can run two large items at once. 48v means smaller and fewer Solar Charge Controllers a 250/70 would probably handle the above solar just fine vs needing three 150/100 Charge Controllers at 12v. 12v will also use much thicker copper cables - 4/0 vs 2awg for 48v for the main bus.

What do you mean by 250/70 solar charge controller? What do the figures represent?

 

[Hillbilly2]

Thanks all. After pricing some of the components, I have decided that I can't afford to have an Air Conditioner. Attached is a NEW Design Drawing reflecting my estimates of the amount of power I will need without the A/C. I am looking for a recommendations of what you would design for my needs, what size components would be required, what brands of components you would recommend employing. I think under this NEW design, I could employ the 12v Solar Array design as I will not be using multiple 120v items at the same time. I think the idea of employing flexible Solar Panels is better, as my roof is large and they are much easier to install. Really want to make sure I wire the system correctly, have included all necessary components, have included all needed safety devices, and install the correct wire size/capacity. My boat has an outboard that currently charges both the house battery and the starting battery (Separated by a switch) when running. Thanks again for all of your help.

 

[LakeHouse]

I saw that Amazon is offering a 1,600W flexible panel kit for $190

This is not what you think it is. Amazon has lots of scams right now that have misleading info on solar panels. I think some of them are quoting something like the amount of Wh that the pnels could produce in an eight hour day of perfect sun…. So maybe they are 200W panels.
Look at the size of the panels, and if they claim to make more than 200W per square meter (~18W per square foot), the seller is lying to you.
Also, flexible panels have a bad reputation on the forum. Apparently they don’t last very long.

 

[Hillbilly2]

Thanks Lakehouse, that information is helpful.

 

[Rocketman]

I would absolutely use Victron equipment. It is high Quality (marine rated) equipment. It does cost more. (I use Victron in my MotorHome).

For just running your microwave a Multiplus 12/2000 inverter/charger will work.

Shunt - Victron Smartshunt or BMV712

Solar Charge Controller a Victron smart mppt (size will be determined when solar panels are determined).

For monitoring- look at a Victron Cerbo-S and touch.

For solar panels see what is available locally. Often the larger panels 350-ish watts (330w to 400w) are the cheapest. They cost less/watt plus you have fewer mounts to purchase. Pay attention to the $$$/watt. Also before buying get the spec sheet and post with how many you are getting- some combinations are not great and will cost you a more expensive solar charge controller to run it. Yes it will be challenging working with a large 40-ish pound solar panel- but you have the space.

Good Luck

 

[Hillbilly2]

Thanks, Rocketman. Would you employ an flexible 800W (2 400W) kit which is on sale at $283?
[https://www.amazon.com/Controller-F...sprefix=400w+solar+panels+kit,aps,221&sr=8-19]

 

[LakeHouse]

Thanks, Rocketman. Would you employ an flexible 800W (2 400W) kit which is on sale at $283?
[https://www.amazon.com/Controller-Flexible-Monocrystalline-Battery-Charging/dp/B0CQC5YMML/ref=sr_1_19?crid=12MSST5M3CQY1&dib=eyJ2IjoiMSJ9.KF7rCovVsqK51TdWpeT4N5Ak4OHCv6Opj7klGtY-ZtWTlI173YuyNqtWAO8VzsVymSWjj-ac0moqNoLB27fjYhlWKTtIiw6J1978Dw8otQo9t38sYaluOuR7vFrEQWsxv4qPXYe0JnOF736Vo0MZ9TsQZdOT8QdZxBaULDGv-omRqdAoe_1dE8HunKhKSs3tg52NETQjPz5-a_ngkRsM3q12aD3P7J4eDSr9aDGwlJw.Dd-AU29FH2RUZMPDefQikrJm0ebdCiJwXcViUrRb4us&dib_tag=se&keywords=400w+solar+panels+Kit&qid=1708116814&sprefix=400w+solar+panels+kit,aps,221&sr=8-19]

I hate sounding like a broken record here... But definitely a scam (or at least very intentional false advertising) and definitely not 2 x 400W panels.



25V times 8A = 200W. So even if they made the max voltage and max current (I guarantee they won't), it wouldn't make more than 200W.


Also, 1.18m * 0.54m = 0.64 square meters. At 200W per square meter, that's a maximum of 0.64*200W = 127W. And that's if the entire thing were high quality solar cells. They are not that.

My guess is you won't ever get more than 100W out of one of those panels.

 

[Rocketman]

Thanks, Rocketman. Would you employ an flexible 800W (2 400W) kit which is on sale at $283?
[https://www.amazon.com/Controller-Flexible-Monocrystalline-Battery-Charging/dp/B0CQC5YMML/ref=sr_1_19?crid=12MSST5M3CQY1&dib=eyJ2IjoiMSJ9.KF7rCovVsqK51TdWpeT4N5Ak4OHCv6Opj7klGtY-ZtWTlI173YuyNqtWAO8VzsVymSWjj-ac0moqNoLB27fjYhlWKTtIiw6J1978Dw8otQo9t38sYaluOuR7vFrEQWsxv4qPXYe0JnOF736Vo0MZ9TsQZdOT8QdZxBaULDGv-omRqdAoe_1dE8HunKhKSs3tg52NETQjPz5-a_ngkRsM3q12aD3P7J4eDSr9aDGwlJw.Dd-AU29FH2RUZMPDefQikrJm0ebdCiJwXcViUrRb4us&dib_tag=se&keywords=400w+solar+panels+Kit&qid=1708116814&sprefix=400w+solar+panels+kit,aps,221&sr=8-19]

Nope…

I don’t trust flexible panels- especially for an area that doesn’t require them.

If I had a large roof, I would find local 330w to 400w panels and and get those. I am helping my brother-in-law and we found 390w panels in a nearby city for less than $.50/watt.

Connected to a good Victron Solar Charge.

 

[Hillbilly2]

All, Thanks again for all of your help in my project. I have followed your advice and looked locally for non flexible solar panels and found 3 new 540W panels for $130 each. I am going to travel there and pick them up Wed. I plan to glue mount them on my fiberglass houseboat roof using plastic mounting pedestals' ( https://www.amazon.com/gp/product/B0CNQ8Y8SR/ref=ppx_yo_dt_b_asin_title_o02_s01?ie=UTF8&th=1). Any advice on mounting the panels or routing their wires to the roof pass through point?
Will I need to run the three sets of output wires through a Solar wire combiner box like this one (https://www.amazon.com/gp/product/B09Q5H81BG/ref=ox_sc_saved_title_1?smid=A2VILSBUHD1UD8&psc=1) then pass the 2 resulting output wires through my roof to my controller/inverter/combination?
I have also found a smaller 8,000BTU AC that would require less power. Can it be powered with the 1620W produced by the three solar panels along with my Frig and Microwave?
Based on this solar power, which controller or combination controller/inverter I should look at and how big should my inverter be? Again, I am looking for the least cost selection possible.
Last question is what size wire should I use to run from the combiner to the controller/combination inverter?
Obviously, my next question will be your recommendations on what type, brand, size, and number of batteries I should employ.
Thanks again for all of your help.