Wetdream solar 100% electric Catamaran

[yabert]

I took time to do a better rough 3D of the 45' Catamaran we plan to buy.
With 16 panels 640W that look good for a 10.2 kW array.
Pattern should be 2 panels in serie for Vmp around 73V and 17.5A. Add another 2 panels in serie to create a parallel string of 73V 35A connected to a Victron 150/45.
Do this 4 times and that seem good.

The surface of panels compare to the surface of the Cat on water look good to me as they don't take all the space.

 

[yabert]

We now have the donor sailing catamaran for the solar/electric conversion
45 feets custom Lock Crowther Spindrift who need a good amount of love.

 

[JBoffgrid2022]

Bi facial gain on the water would be incredible if you were to somehow be able to gather sun rays from the sky and rays from the water reflection. I would definitely consult an engineer that could calculate the ballast weight loads of the panels AND any potential force brought about by high winds. I know catamarans are very stable, but it would still be a good idea to make dang sure of this beforehand. I'm interested also on how the panels might effect your visibility, wouldn't it create a "tunnel vision" effect? To me, it would defeat the purpose of sailing and being on the water if I were feeling like I was always passing under a bridge! lol.
These are only my opinions here of course.....
No criticism intended!

 

[ULR]

Reasons to leave the mast and rigging on, or at least replace it with SOMETHING (high and strong):
- A standard hack to prevent full half-turn flip-over on a multi-hull is to mount a float at/near the top of the mast. If you DO get knocked down, the float keeps it from going to the upside-down stable position by providing upward force on the mast top. (Doesn't take an ENORMOUS float because of the lever arm, but it does take more than just a bumper.) The boat may pause at a quarter-turn (mast horizontal) but (if I have this right) either gets thrown back up to normal orientation by wave action or at least can be flipped back with a MUCH smaller effort that getting it out of the upside-down position. (I'm NOT a multi-hull sailor or expert so research this yourself. Please!)
- If your electrical system totally dies you can raise some sail and move (even if you only have a small rig, like a stormsail. SOME drive is SO much better than NO drive.)

 

[ULR]

Bi facial gain on the water ... I would definitely consult an engineer that could calculate the ballast weight loads of the panels AND any potential force brought about by high winds.

Load from weight and winds? How about load from a storm or rogue wave that breaks over the boat and onto the panels? SWAT! For a few seconds the panels have to support that water's weight AND deflect its momentum.

 

[JBoffgrid2022]

Load from weight and winds? How about load from a storm or rogue wave that breaks over the boat and onto the panels? SWAT! For a few seconds the panels have to support that water's weight AND deflect its momentum.

True, but any of these issues would ultimately depend on where the boat would be sailed. If the boat were going to be rounding Cape Horn, I'd say no way. But if it were for smaller one or two day trips not during hurricane season, I'd say go for it! Either way, the idea is cool but will definitely need a lot of planning ahead of time

 

[yabert]

Bi facial gain on the water would be incredible

It's the plan. I still learn about hailstone and storm resistance differences between bifacial and single face panel.

I'm interested also on how the panels might effect your visibility, wouldn't it create a "tunnel vision" effect?

Right, especially for front view (in blue).
At least, side vision (green lines) and chilling on the front trampolines will not be like under a bridge

 

[yabert]

If the boat were going to be rounding Cape Horn, I'd say no way. But if it were for smaller one or two day trips not during hurricane season, I'd say go for it!

It's exactly that. Limited range for 1 or 2 day trip of around 100 nautical miles maximum.
Stay at a nice place few days and then, when batteries are fully charge, let's go for another trip.

 

[JBoffgrid2022]

I was thinking, have you explored the "peel & stick" panels? I was thinking you could potentially get a lot of your power from this type of panel and maybe reduce the size of the other larger panels. Just a thought

Sunflare Flex 42 Adhesive Solar Panel

The lightest and most low profile adhesive solar panel I've found to date! Featuring bypass technology that enables the panel to work in partial shading conditions, this panel will produce power under any conditions thrown at it. Standard solar panels suffer when even a corner of it is shaded...

adventurepowersolutions.com

 

[yabert]

power from this type of panel

This type of panels have generally poor efficiency. In other words, they take a lot of space for the same power output.
Those sunflare are give at 11% efficiency and I'm looking at 22-23% efficiency rigid panels.

 

[sailingharry]

Several comments:
1) The posts about flipping are bogus. Cats basically only flip when they have too much sail up. They can also, I guess, flip in extreme seas (think Cat 1 hurricane at least) -- where your propulsion would be laughable. This isn't a place you'll ever be. And cats the size you are considering don't get saved by a float at the masthead or by levering it back up -- when they get over, it's all over. But it's a complete non issue unless you somehow plan on being 100 miles off shore in 40-50 foot seas....
2) I have had my 43' monohull in a place where full throttle on the 50hp engine had me going someplace between 1 knot, and backwards. This was only winds of 30 kts. While this is extreme, I doubt that with a more typical 15-20 kts on the nose your cat would make even 2 kts with the motors you are planning -- and that is full throttle burning batteries fast. You might want to somehow borrow a15-20hp outboard and mount it on the back of your boat, and go out in a 20kt breeze (20kt is not storm conditions -- it's normal stuff).
3) You mentioned the Caribbean. Even getting to the Bahamas is probably out of reach with the range/speed you can make, not considering seas. Getting further (and that path is against the trade winds) isn't going to happen. Get out your map and look at the distances involved.
4) 100% coverage overhead addresses one of the big problems with sailboats -- getting out of the sun!
If you set your expectations low, this may work. Plan on short days (while your RANGE may be long, an 8 hour daily run can get tiring, so count on 40 miles a day). If you want to make significant time, you'll need to pay for marinas each night -- solar recharge would take idle days. Plan on staying put (anchor or marina) on days when the sun doesn't shine or the wind is against you. Stay inland (being half way between two inlets 100 miles apart when the weather goes lousy is not good when you don't have good power or sails). By "significant power" I would want to see a pair of 20hp/15kW to provide headway in adverse conditions. But if it fits your desires, Indigo is an excellent example -- however, in a breeze through his Youtube interview he didn't mention handling and range and recharge issues.

 

[yabert]

Several comments:

Lot of good comment and they seem to come from experiments.
1-Good to know. Many people are worrying about flipping a Cat who is 22' large with a center of gravity probably around 3-4 feet above waterline.
I plan to literally have 1000 lbs of battery under waterline in each hull.
I still evaluate all this.

2-I bet this kind of situation would force us to return, down wind, somewhere to wait for better weather.
Even if I had two 100 hp motors to gain against wind, the battery will be drain in less than 1h... so no sense.

3-I hope I calculate correctly, but I don't see any place with more than 100 nautical miles between islands.
Miami, Bimini is only 51 NM. Next destination only 80 NM and most other island are less than 50-60NM from each other.
The longest trip appear to be Turks and Caicos Islands to Dominican Republic who is 100NM. Right?

4-Yeap, almost all new boat offer a lot of shade, so what is the problem to have solar panel overhead? Nothing, if you ask me.

 

[sailingharry]

3-I hope I calculate correctly, but I don't see any place with more than 100 nautical miles between islands.
Miami, Bimini is only 51 NM. Next destination only 80 NM and most other island are less than 50-60NM from each other.
The longest trip appear to be Turks and Caicos Islands to Dominican Republic who is 100NM. Right?

I was very wrong, and you are right. There are basically no trips over 100NM. In fact, Indigo is currently in the US Virgin Islands, with range restrictions similar to your plans. Indigo did make some comments in a post about timing weather to get east, as the trade winds hurt him more than most boats -- but he did it.

 

[yabert]

For those who think the 12 kW array on my Cat could cause problems during high wind... what to think about Arkup proposition of their 12 kW array

 

[sailingharry]

Well, the marketing is handled by their marketing team....LOL
It's 50' long, and it has a 50kW/67hp motor, which is quite reasonable (many EP boats massively undersize their motors).
It reaches 8.5 kts, and I believe it.
The battery (75kWh) can run the motor (50kW) for 1.5 hours at full speed, or 12 miles.
500 miles on battery alone means, well, lets assume you run the boat at 5% power (3hp, maybe 1 knot), then you can get ~30 hours or 30 miles. The range is a lie, based on the 15kW generator giving about 20hp to the motor, probably a 6kt speed (and probably a 100 gallon tank).
The recharge is a lie too. It claims full recharge in 6 hours -- but you don't get 6 hours of full power in a day. Realistically, it's closer to 3 effective hours, meaning it's two full days to recharge (which frankly is pretty damn impressive!).

 

[yabert]

well, lets assume you run the boat at 5% power (3hp, maybe 1 knot), then you can get ~30 hours or 30 miles

Depend. No wind probably a bit faster like 2-3 knot IMHO. Our 38 ft monohull did 3 knot with around 1 hp.
Now, with front wind it's probably like 2-3 knot backward

How much this Arkup 50 weight? 100 tons?
In their 75ft Arkup specification it's wrote 268 tons
Our Catamaran should weight around 10 tons, so that looking good for us.

 

[yabert]

I'm looking for advice about monitoring different devices on this solar boat. There will be:

-4 to 10 MPPT: I don't see any reason at the moment to use something else than Victron smart.
-2 batteries (16S and 70 to 85 kWh each): BMS isn't choose at the moment, but some communication is a must.
-2 motor controller: probably Ezkontrol so they can communicate via bluetooth, CAN-BUS, RS485 or UART.

So, how can I monitor all those devices?
3 different app on a tablet/cellphone? Possible to put all this on one screen?
A Victron Cerbo or Ekrano?

Please let me know if you have clue about this.

 

[sailingharry]

The Cerbo can certainly handle the MPPT. Unfortunately, Victron doesn't make a BMS (what they sell is an enhancement to their battery -- it's more like a VMS (Victron Management System) and is incompatible with any other battery or DIY project. It's a serious omission in their ecosystem. Some BMS (Electordacus) can be made to play well with Cerbo.

I'm not entirely sure how you would "integrate" the motor controller into a Cerbo (what do you want it to show?) or why you would even find "communication" to be useful. Amps in/out of the battery is easily handled by the BMS. Throttle position is handled by the throttle. I'm sure there are configurations/settings that would be very nice to have access via WiFi or BT, but that's not an ongoing thing.

If it were me, I'd get the battery stuff (MPPT, inverter, chargers, etc) integrated into a Cerbo to see instantly the battery status and such, and a throttle lever for the motor controller.

A thought about 150kWh or more of storagte. If you want to drift into the marina on fumes, and leave the next morning, you need 10 kW of chargers. Here in the US, where shore power is usually 120V, that's almost 100A of shore power -- or two 50A cords, and sufficient chargers.

 

[yabert]

I'm not entirely sure how you would "integrate" the motor controller into a Cerbo (what do you want it to show?) or why you would even find "communication" to be useful.

Motor amps, temperature, rpm.
Controller temperature.

Here in the US, where shore power is usually 120V

Yes, 120V and only 30A, right. So even 24h plug on shore power only add around 72 kWh of energy.
There is no doubt, that solar array need to work very well and we are in way for slow travel.

 

[sailingharry]

Motor amps, temperature, rpm.
Controller temperature.

In theory, you could add a dedicated data page to the Cerbo that gave those three things, but I'd think they would be much more useful on the engine control panel. On my boat, with a diesel, I have mechanical meters that show RPM, Motor Temp, and Oil Pressure, and I look at them often when under way. RPM is a very frequent check. I just can't see going to a Cerbo (which would, I guess, show amps in/out and devices doing that) to get "engine operating parameters." Any display giving that information should be waterproof, sun proof, always on, and front-and-center for the operator to see.

 

[yabert]

I just realize that using two Victron 150/100 is also an option.
Config should be 3 panels in series (around 100Vmp), then 4 string in parallel to input around 60A at MPPT.
6000W / 58V (battery nominal V) = 103A

Man, I'm now more confuse about what is the best configuration between 2 mppt, 4 mppt or 10 mppt
Of course, monitoring 2 mppt is way simpler. That an advantage for sure.

 

[yabert]

Two good stuff to share today:

1-I just receive my first Victron MPPT and I realize they can be set up to 69V. Nice.

2-I just realize that I could probably use 360V EV motor in our Catamaran. Only the motor and no gearbox, no 360V inverter.
They can be find for cheaper than boat or motorcycle motor available and they are way more rudge.
As I plan to run them at around 60V, they will spin around 6 time slower than 360V, but this is almost perfect at 1000-2000 rpm instead of 6k-12k rpm.
Sure power will be 6 time lower, but from 100-150 kW to 17-25 kW seem good.
I have eyes on old Nissan Leaf motor, old Kia Soul motor of even Isuzu imiev motor.
I choose those because their motor are full independent from their transmission/inverter. So no need for a gearbox rework.
Any other suggestion of motor?

 

[yabert]

I've just test the theory of running a 360V EV motor at 52V with a low voltage controller and it work
So this ASI BAC2000 controller run this Smart Fortwo EV motor without problem sensorless.
I'm really happy because those motor are rudge and affordable.
I still plan to use 2 Nissan Leaf or Hyundai Kona motor for our solar Cat.

 

[AnarchyJet]

2-I just realize that I could probably use 360V EV motor in our Catamaran. Only the motor and no gearbox, no 360V inverter.

Do the boats you are looking at have saildrives or shafts? If it is shafts, don't forget about some type of thrust bearing.

 

[yabert]

Shaft drive. Good point as I don't want the motor bearing to take this load.