Designing a Solar system for mini Houseboat

[Rocketman]

Wow - those are massive panels. You will need help getting them to the roof. Can you get four panels? And fit four panels. Four is a much better number than three.

with four panels you can do 2s2p. (Two in series then two in parallel). With three you run into issues with too much Voc if in series and too many amps if in parallel.

What are the exact specs on the panel of:
Voc
Vmp
Imp
(All the below guess may be incorrect until we verify the exact specs of the panels.

Were you still planning on a 12v battery or 24v or 48v. The higher the battery voltage the fewer solar charge controller you will have…

At a 12v battery the 590w panel will provide 45amps at 13v - So the cheapest charge controller would be each panel connected to a Victron mppt 100/50. You will need three or four at &184.45 each.

https://www.continuousresources.com/collections/mppt-solar-charge-controllers

(This is my Victron dealer).
You could connect two panels to a mppt150/70 $414.80 (slightly clipped) or a mppt 150/85 $453.05.

Now if your battery is 24v and you get four panels in 2s2p. You only need one mppt 150/70 (slightly clipped) or one mppt 150/85.

If your battery is a 48v and with four panels in 2s2p you could use one mppt 150/45 $218.45.

You will find the inverters cost about the same, 12v vs 24v vs 48v - the wiring will be much smaller with higher voltage - less copper = less cost. The batteries will be about the same too. 400ah of 12v vs 200ah of 24v vs 100ah of 48v.

You will have some converters to factor in…

Your other question of running the air conditioner - that depends on if you buy an inverter that can power it - then it needs to get the power from batteries and solar.

2360w of power when sunny at noon will supply enough watts to run the air conditioning, however when it is cloudy I only to 10% to 20% rated power - so 230w to 460w is not enough and you will be pulling from the battery.

 

[Rocketman]

I have no opinion on those brackets - one thought are your panels too big for them?

When we installed my panels we got alum “L” 2” x2”x .125 or.187. Cut it into eight 6” pieces- mounted half to the solar panel bolted with 1/4” bolts then screwed the other half to the roof - made our own “Z” bracket. With those big panels you may want one or two more pieces in the long middle runs. Easy.

Let’s finish solar and battery voltage before moving onto other areas.

Let me know your thoughts.

PS don’t buy anything until you have the whole system figured out.

 

[Hillbilly2]

Thanks for your help, Bases on your advice, I will get four of the 540W panels today.

 

[50ShadesOfDirt]

I don't know the particulars of your houseboat, but I'd suggest the following:

Phase 1: Start with an inverter/charger, battery-bank, and generator. Normally, a generator (fuel type of your choice) would run 24-hours, but you'll find that with a battery-bank, gen now runs only about 4 hours or so. Also, given CPAP, I'd have a gen in the mix, for emergency power. Finally, a gen with good auto-start capability (fob, auto-choke, etc) means you can run all the heavy loads that will pop up with a houseboat and crowds of guests ... A/C, microwaves, etc., and possibly still be charging the battery-bank back up (depending on sizing). This also gets you up and running pretty quickly. A good gen box, and everything is noise-muffled and weather (splash) protected.

After running for awhile, now you've got a good handle on your loads and operational patterns.

Phase 2: bring in the solar panels & mppt portion of solar gear. If not victron (component route) and will be AIO, then don't need the mppt, as it's built-in.

Hope this helps ...

 

[Hillbilly2]

Thanks 50Shades. Rocketman, got four new 540W Heliene panels today for $125/ea. ($.23/W). Attached are photos of their Data Plates for your viewing. Just to put everything into perspective, also attached is a photo of the boat. It is not the large size most people think of when visualizing a Houseboat. As stated earlier, my goal is to be completely self-sufficient in power as it will never be tied up where there is electricity available. My major energy draws will be; 12v lighting, a 120v 4.5CF Frig, a 1,000W Microwave/Conviction Oven, a CPAP machine at night, a 12v 22" TV (3 hrs.), a 120v fan at night, and, now that, during the sunniest part of a day, I might have 2,160W of Solar Power, a 13,000 BTU roof mounted air conditioner. I only plan to use the A/C during the hottest part of the day, thus, I am hoping that the solar panels might power it without draining much battery power. You mentioned in your last post, that 2360w of power is sufficient to run an A/C. What size AC (i.e., BTU) were you referring to?

Each panel seems to weigh around 50 lbs., so I think my planned plastic mounting corner/side riser stands should support them and allow me to glue them to my roof (with a few roof screws in the mounts along the roof edge). Per your advice, I have ordered two additional side stands for each panel which will support each panel every 2 1/2 feet along their long sides. In your opinion, what is the best, weatherproof heavy Duty adhesive/glue (like Gorilla Construction Glue/Epoxy, etc.) to use to secure their plastic stands to my roof.

You mentioned 2c2p wiring of the panels to reduce the need for (thus cost) of multiple controllers. Where should I research how to learn how to do this? Also, for off grid houses, they often install a combination controller/inverter device (e.g., Growatt 3kW Inverter, etc.) , which might save the cost of the controller(s). You have any advice on that?

Finally, as my next step is to install the panels on my boat's roof, how do I combine/aggregate/etc. the 2c2p wires so I only have to pass 2-4 wires (? AWG) through a single hole in my roof to the controller(s)?

As always, many thanks for all of your help.

 

[robbob2112]

I am going to throw my 2 cents in. You would be much better off going with a 48v battery and inverter/charger. The wires, bus bars, fuses, etc will be a fraction of the size and more important a fraction of the cost. Also less chance of a bad connection causing a fire from the heat. Instead of 200amps you would have 50 amps, just an example. For your 12v systems you can get a 48v->12v converter for not a lot of money.

And to parrot what the folks above said ....

BUY NOTHING ELSE UNTIL YOUR PLAN IS COMPLETE...

buying stuff piecemeal means mistakes are costly and you can end up with equipment you don't need and can't use. Don't ask me how I know.

I use a cpap at night and you may want to think about a separate battery backup that you run from at night and you top up each day. I built one out of a 12v 100ah mini LiTime battery and a few other components. I run the resmed asv with heated climateline tubing and the humidifier on. It consumes 25% of the battery each night and refills from the wall charger in the day. I say separate because that way you would never chance draining the batteries and having nothing at night. Better safe than sorry.

 

[Hillbilly2]

After having purchased four 540W solar panels for a potential total of 2,160W during direct sunlight, I have updated my (attached) planning solar system design diagram. If anyone viewing were to be installing this system on your tiny houseboat, h ow would you populated it with the correct size components in your favored brands (i.e., How would you Fill In the Blanks).

 

[Rocketman]

Nice little houseboat - my vision was a little bit bigger.

These are the specs on the four 590w panels:
Voc 49.97v
Vmp 42.13v
Imp 12.70a

I can’t help on glue that sticks to plastic and the roof of the houseboat - (is it fiberglass?)

Ok now it is planning and measuring time.

The largest load you want to power is the air conditioner- we need to get the specs on it so the inverter can power it. Is it 120v? What amps does it use and what are the LRA (Locked Rotor Amps). What does it say in the manual & what make and model.

What space do you have for batteries and the other equipment?

And what voltage do you want your battery/inverter system: 48v, 24v or 12v. The higher the voltage the fewer charge controllers are needed and the smaller wire (less current and less copper).

With batteries it is best to buy the battery the same voltage as the inverter- a single 48v battery rather than four 12v batteries in series. The same with 24v - a 24v battery rather than two 12v in series.

 

[Hillbilly2]

Air Conditioner info: Dometic Brisk II Evolution 13.5K BTU 115 VAC, 60 HZ, 1 ph ​

Compressor Amps; Rated Load: 12.4A, Locked Iotor: 68A --- Fan Motor Amps; Rated Load: 2.5A, Locked Rotor: 2.5A (the manual's chart says Locked Iotor rather than Locked Rotor, so that is the way I wrote it)​

Battery Space: 48+"L x 15+"W+ x 15+"H- Room enough for five + large batteries.

Controller/inverter/other components space = cabinet 48+"W x 24+"H x 12+"D (behind one of the Dinette's seat's backrest). Should be adequate room for any components needed. Will be Controller or inverter get hot when the batteries are not recharging, thus, require venting?

Voltage for battery/inverter system: Looking to determine the best design. Per your comments on wiring the solar panels 2c2p if that is best. I have numerous 12v lights, and plan to run my CPAP, TV and water pump on 12v. Frig/MW/AC, etc. on 120v.

I'm open to buying the best controller(s)/inverter/battery brand/configuration/voltage that is best for my needs.

Per my design diagram, I plan to put a shore power or generator female receptacle on the boat, so, if I am ever parked next to a 120v outlet or have to recharge using a small generator, I can plug it in.

Again, thanks for all your help, as I am completely ignorant in what I'm designing.

 

[Rocketman]

Ok, on the air conditioner you will probably (definitely) need an EZ start to lower the 120v amp draw. I used Micro Air EZ start it dropped the actual startup amps on my Air Conditioners from 27.4 amps to 15.3amps and 27.9amps to 16.5 amps. Much easier on the inverter.

For Equipment I use and Love my Victron equipment. It is high quality, Marine rated, really good software/firmware, and the manufacturer stands behind the equipment with the warranty.

You could also go with an AIO (All in One), they are probably a bit cheaper, I can’t help much with what brands are good or not because all my experience is with Victron.

If going with Victron, your inverter will need to be a 3000w inverter- that will allow you to run one high draw item - air conditioner or microwave or coffee maker or… (you can run all your low draw items without an issue).

For voltage- the higher the better 48 is better than 24 which is better than 12. You “can” go 12v but it will involve either 4/0 wire or 2x1/0 wire for the main lines and they will draw massive amps. The higher the voltage the fewer the mppt’s that are needed.

 

[Rocketman]

Batteries will be a bit of an issue into your space.
It is too small for any of the rack mount batteries.

I did find some 48v 100ah batteries that you could get two of these into the space.

I did find some 24v batteries (200ah) that you could get two of those batteries into the space
(Both of these are LiTime - other than it fits I know nothing about them other than they are advertised a lot. Look up reviews on any batteries you are considering.

A 48v 100ah battery has the exact same storage as a 24v 200ah battery and a 12v 400ah battery- these were 8D group batteries.

Because you want to run the air conditioner, you probably need 2 of those batteries.

There are lots of 12v that will fit - (if you go 12v highly consider a Victron Power In as a battery bus bar - or some other high quality copper bus bar - because you will be dealing with very high amps).

This is the Victron equipment you should look at:
Battery Monitor: Smartshunt or BMV712
Inverter- Multiplus v?? /3000
SCC’s Victron SmartSolar MPPT’s size???
Converter - to step down to 12v (if needed).
Victron Power In - bus bar and a distributor bar.
Edit: Cerbo and touch.

A lot of this equipment depends on the voltage selected. That is your next real decision.

Also look up the sizes of all the equipment and make cardboard cutouts- tape them up in place and make sure everything fits.

 

[Rocketman]

For batteries- these are the essential features- in my opinion… ( and why)
1. Bluetooth (or another way to connect to the bms). You need to know if the battery cells are getting out of balance- so you can adjust settings to fix it.
2. Low temp cutoff. The bms MUST prevent low temp charging- I will also have the other charging sources prevent charging too. If you charge lithiums below 32F - it will ruin them.
3. Good reviews from someone that tested the battery- hopefully Wil Prowse.
4. Size - it needs to fit in the space.
5. BMS the same voltage as the inverter. Having 2 or 4 batteries in series is asking for headaches down the road. Yes it can be done - buy why?

 

[Hillbilly2]

Great, Please talk to me, or direct me to an article that teaches me how to wire the solar panels for the 48v system and pass them through my roof to the next step, in the design you think will work best with the equipment you have suggested.
Also, does the Victron v48, 3000W inverter include the Controller function in connecting the panels to the batteries?
Thanks.

 

[Hillbilly2]

Rocketman, After looking up the cost of some of the components you recommend, I have found that, installing and using an air conditioner on my tiny houseboat will cost me, at least, an additional $5,000. I don't really feel that having an air conditioner is really worth that high cost. Thus, I have redrawn my system design drawing to remove the air conditioner power requirement.

Under this design, my 120v demand will be only for the Frig, Microwave, fan, coffee pot, and other plug ins.

By doing this, should I still install all four of the solar panels or a lesser number. If a lessor number, how should they be wired (Parallel, Series, or 2c2p)?

Based on this revision, what are your recommendations for the Controller, Inverter, monitors, and batteries (Brand/type, # & Ah).

As always, thanks for your help.

 

[Rocketman]

The wiring of the big solar panels through the Solar charge controller depends on the system voltage (battery voltage).

I know Victron is expensive, there are some other brands that are cheaper or other architectures (all-in-ones) that can be cheaper too.

Are you still going 48v?

 

[Hillbilly2]

Depends on how many of the four panels I install. Looking for advice with my smaller (No A/C) system design. How would you do it if it (Panel wiring, Controller(s), Inverter, Batteries, interrupters, etc.) was yours?

 

[Rocketman]

Realize that I am a Victron Fan. So here is what I would do.

The cost difference between a Multiplus 2000w inverter and a 3000w is not much, because of that, I would use a 3000.

Here is what I would do and use and the upgrade path I would use.

Install one 8D sized 48v 100ah battery- install in a way to add another at a later date.

Victron Smartshunt
On/Off switch
ClassT fuse or MRBF fuse(on each battery).

Victron Power In (w/fuses attached see YouTube)
Multiplus 48/3000 inverter
Solar MPPT 150/45
(Your four solar panels in 2s2p).
48 to 12v converter.

Because you will be large on Solar and low on battery great communication is for me a necessity. I would install the Cerbo and Touch. That way everyone can easily know the status (how full/empty) the battery is and how much solar is incoming. You could just use a phone and Bluetooth to look everything up, but it is harder to understand for everyone on the boat. (If not going with Cerbo & Touch - consider changing battery monitor from SmartShunt to BMV712 - that way you have a display of battery stare of charge in the living area.

The big cost is upfront, later add the Micro Air EZ start and then a second battery and you achieve the goal (in a year or two) of running the air conditioning on the boat. You could also wait on the Touch until the second expansion and just use Bluetooth to read the info from the Cerbo. The Cerbo also controls the inverter (on/off/inverter only charger only & 120v input amps).

With only one battery you will probably lose some of the surge potential of the inverter- but you probably will not need that until you use the air conditioner.

With the Multiplus you can use the small generator to run the air conditioner or when at dock - plug in and the Multiplus will charge the battery.


There are many ways to build something, you could get a cheaper inverter (pure sign wave) and a transfer switch (for generator and dock) and a charger (like the Chargeverter).

There is also the All-in-One’s but I know very little about them.
Good Luck

 

[Hillbilly2]

Rocketman, Is this the basic wiring diagram for wiring the four solar panels in 2c2p?

 

[Hillbilly2]

If the 2c2p wiring diagram is correct, will I need to place in-line fuses (10/20/30/40/50A) in the positive wiring or should I plan to place a circuit breaker in-line on the positive single wire before the controller? I watched this video, and it mentioned that I might need fuses in-line on the positive wires before each 2-1 wire connectors. ( https://video.search.yahoo.com/yhs/...080d3a2d930431d8fb60813cafd351a8&action=click )

 

[Hillbilly2]

I know that I am asking a lot from you, but I am so ignorant about solar system design, that your help is mandatory. Can you add a correct product URL/Link (to the cheapest source you know of) for each of the components you suggest so I can buy the correct products?
Multiplus 3000w:
8D sized 48v 100ah battery:
Victron Smartshunt:
On/Off switch:
Victron Power In (w/fuses attached see YouTube):
Multiplus 48/3000 inverter:
Solar MPPT 150/45 (Your four solar panels in 2s2p):
48 to 12v converter:
ClassT fuse or MRBF fuse(on each battery):
Cerbo and Touch:
Solar MC4 Connector T-Branch 2 to 1 Splitter MMF + FFM Pair:
As always, thanks a million!!!