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Hello Electric Boats forum!

Any and all thoughts and suggestions are highly appreciated regarding a wooden all-electric boat being built right now. Below are some basic details describing the wooden boat and the proposed electrical components, some of which have already been purchased (motor and motor controller).?

We also have a short youtube video describing where we think the electrical components might reside in the boat, and it also shows the space constraints we are dealing with, we hope this helps explain what we're working on. We haven't build an electric boat before so in a sense we don't know what we don't know. Lots of work still to be done but we wanted to reach out to this group now to get your thoughts.

Electrical components: A 5 minute video showing space constraints and component placement:

Full boat walkthrough: A longer walkthrough video showing progress update of entire boat:

We would like to hear your suggestions and thoughts on the project regarding the electrical system! All comments welcome. We especially would appreciate thoughts on:

Batteries: We don't want to build our own and don't want to manage a BMS (besides programming the hybrid inverter/charger to charge the bank); safety is our top priority, and we think we have a good candidate in the 48V Simpliphi series (more details below). Any thoughts on other off the shelf 48V Lithium solution that might work better for us, considering the space constraints?? We show the bunk where the batteries will go in the shorter video on the electronics here:?

Placement of components: We think we have a rough idea of where the major components and busbars could go; the quick video walkthrough shows some cardboard mock-ups of where things could be placed, but we might not be considering something important.

Solar panels and off-shore charging: Flexible might look better and have some other benefits given the shape of the roof (see the longer youtube walk-through second video at 2:29 ); but rigid panels might hold up better under wind, for example when the boat is being towed down the highway, and last longer in general. Suggestions on panels and wiring? We haven't even begun really investigating the solar side yet, still focusing on the main 48V bus and the shore charging system. Would wind power be worth considering?

Ok, on to the details:?

The boat: Gavia

Description: Gavia is a 25’ all-electric solar motor boat under development. We are now at the stage of investigating the major electrical components with a purchase timeline of 3 months or so (around June 2021).

48V DC System: The motor is a brushed 7.5 kW DC 48V Thoosa Electric Motor. We hope the nominal draw will be around 1-2 kW while under way, but short bursts (1 minute) of 7.5kW are expected (we have not tested the boat in the water yet). Energy will be provided by a 48V lithium-iron battery bank, hopefully with more than 10kWh of usable energy. Solar cells on the roof will be the primary recharge method, hopefully 1kWp or greater, with AC shore power and backup 1kW generator for AC charging. A hybrid inverter/charger should be a convenient way to pack lots of functionality into one box, and AC input/output should be 120V (we are in the USA).

12V DC System: The 12V DC system will be used to run low-wattage house electronics (navigation, radio, windless, house lighting, etc), and 12V bow thruster whose max draw is 1500W. This larger 12V draw necessitates a 12V energy bank (vs relying on DC-DC converter), so a 12V 100A lithium battery will be used and it should recharge from the main 48V system via DC-DC converter charger.

120V AC: 120V AC will be used for a minimum number of appliances onboard, the largest of which is the induction cooktop with a 1800W draw. This will be provided by the hybrid inverter/charger.

We like what we see with Victron and the component integration is appealing. We’ve looked through the sample system designs from Victron and PKYS and our setup probably won’t be too different. Size and weight are major limitations, especially for the 48V battery bank and inverter/charger

Here are some proposed system components so far:

1. 48V Battery: SimpliFi AmpliPhi-3.8-48V wired in parallel (x4 at least)

2. Hybrid Inverter-Charger: Victron MultiPlus-II 48/3000/35-32 120V PMP482305100

3. Charge Monitoring: Victron CerboGX + GX touch 50

4. DC-DC Converter: Victron Solar Charge Controller

5. 12V Battery: Any 12V lithium iron 100Ah+ battery should do fine

6. Solar Panels: Unknown - Flexible Panels to go on the roof

7. Solar Charge Controller: Victron Solar Charge Controller

8. Bus bars, fuses, switches, protection relays, shore plugs, AC bus: Under investigation

Thanks,

Jay

--

	Jeff LaCoursiere STRATUSTALK, INC. / CTO Phone: +1 703.496.4990 x108 Mobile: +1 815.546.6599 Email: jeff@... Website: Address: One Freedom Square 13th Floor Reston, VA 20190
	? ? ?

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Sounds very fun! Thank you for sharing.?

Were you able to estimate any anecdotal level of interest in electric propulsion amongst the participants??

On Apr 24, 2021, at 09:43, Kai Rabenstein via groups.io <k.rabenstein@...> wrote:

? Thank you Jeff - excellent boat show overview!

Kai Rabenstein

On 24 Apr 2021, at 15:34, Jeff LaCoursiere <jeff@...> wrote:

? I'll spice it up a bit with a quick review of the Anapolis spring boat show.

My business partner and I arrived last Thursday night and stayed at the Anapolis Waterfront Hotel.? Absolutely fantastic place to stay - I can highly recommend.? They have an old nautical theme (of course) with very posh decor, and there always seemed to be two supercars parked out front.? Fantastic restaurant right on the water.? As we sat for dinner one night two 74' sloops made several evening trips with dozens of passengers.

We had spent the last several months trying to decide if we should go, not sure if there would be much of a show due to Covid, etc.? So neither of us bought tickets.? I've pretty much always just wandered onto shows and paid at the door, and it never occurred to me that they might try to limit entry... you can see where this is going.? After unpacking and booting up to check directions, I decided we should try to get our tickets online.? SOLD OUT!? What?? All three days sold out.? Feeling a fool, we called the show desk and a nice lady told me we could try at the gate and we may have a chance Friday afternoon and Sunday morning.

Friday late afternoon we made our way to the Bay Bridge.? The spring show is actually in Stevensville on the far side of the Bay Bridge.? What a monster!? Truly an engineering marvel you should make a point to see.? Parking was $10, directed by and benefiting a local girls swim team.? Parking lot only half full at this point, about 3PM.? Sunny but windy, it was chilly.

I'm used to the Chicago boat show, which is 100% indoors.? This show was a mix of indoor, tent, and outdoor booths for vendors, distributed along a good mile of twisting path.? Every time we thought we had reached the far end of the show it managed to find a way to keep going.? There was a food area at one far end of the show with reasonable local fare - lots of lobster rolls, crabcakes, and Old Bay.

I was a little surprised but quite happy with how seriously the public in Anapolis and all the attendees at the show were taking Covid precautions.? I didn't see anyone flouting the mask rules or causing trouble, and now I have a square shaped bikini tan on my face, the only part that didn't get sunburnt.

Standard vendors - lots of rigging, props, electronics, and all the hangers-on to every show (why are there always knife makers at these shows?).? There was one fully electric boat for sale, made in Europe and sold in Miami.? I am shuffling through my papers trying to find their brochure.? I'll forward it when I find it.? It was a cool little runabout.? We talked with them for a LONG time because... IT IS SHIPPED WITH AGM.? I really couldn't believe it.? A new electric boat and you guys are powering it with AGM?? They may soon be one of our bigger customers!

We saw an e-propulsion vendor there, and some of their new products.? They also claim their battery packs can be submerged and float.? I spent some time examining their larger packs; they looked like they belong more in a computer machine rack than in a boat.

Then there were the BOATS.? Docks and docks and docks of boats to see.? Many were for sale by owner, though the usual cast of manufacturers had representative yachts for viewing.? My absolute favorite was an older Hylas 56, absolutely beautifully maintained.? I find such a stark contrast between the finishes in the newer super-yachts to that you find in the 20+ year old larger boats.? The Hylas seemed to be carved from a giant block of solid wood, but elegant and powerful.? Across the dock - a massive brand new cat, all the latest electronics, but with finishes that looked more like a facade.? Felt plastic to me.

We stuck around Friday until closing, then came back earlier Saturday to try again.? Much nicer day - wind down, sun out, much hotter.? By the time we got there the parking lot was full, and we were directed to "the old K-Mart, oh you guys aren't from around here, well across the highway, blah blah".? We had to take a bus from there!? Saturday the show was much busier.? We still managed to get in, though after taking the bus ride I had my doubts.

My business partner and I were there to case the joint wrt Marine Battery Sales.? The big question - will there be any competitors to our new venture at the show?? Answer: No.? In fact there was only one battery company at the show, and they had no lithium products at all!? Lots of Lifeline stuff, and it was all on display, but I was really taken aback.? We talked to them for a while and I came to a stark realization.? There really is no "leader" in the lithium market.? These poor guys had been running a retail battery store for 40 yrs (!) and were struggling to understand what lithium products to pickup.? They realized all the tools and testing equipment they were used to using would be changing.? They were anxious!

Mission accomplished, we had a great time at this show.? It was busy, but not like shows I have been to in the past.? I think it was a cautious re-opening, and I am excited that it went off without a hitch.? I am sooo ready to get back to normal.

We will definitely have a booth at the October Anapolis show - the biggest in the world.? Hope to see all of you there!

Cheers,

Jeff LaCoursiere
s/v Angels Quest
St Thomas, USVI

Checkout for our latest lithium adventures...

On 4/24/21 7:14 AM, Carsten via groups.io wrote:

Same here.

Boring...

Carsten

On Saturday, 24 April 2021, 16:38:22 GMT+8, peter snowdon via groups.io <petersnowdon@...> wrote:

I have not received any mail since 1st April. and now when I checked in the group I see there hasn't been any. Is there a problem or is it just that everybody is very busy?
Thanks, Peter Snowdon

--

	Jeff LaCoursiere STRATUSTALK, INC. / CTO Phone: +1 703.496.4990 x108 Mobile: +1 815.546.6599 Email: jeff@... Website: Address: One Freedom Square 13th Floor Reston, VA 20190
	? ? ?

--
Jeff LaCoursiere
s/v Angels Quest
St Thomas USVI

--

	Jeff LaCoursiere STRATUSTALK, INC. / CTO Phone: +1 703.496.4990 x108 Mobile: +1 815.546.6599 Email: jeff@... Website: Address: One Freedom Square 13th Floor Reston, VA 20190
	? ? ?

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Same here.

Boring...

Carsten

On Saturday, 24 April 2021, 16:38:22 GMT+8, peter snowdon via groups.io <petersnowdon@...> wrote:

I have not received any mail since 1st April. and now when I checked in the group I see there hasn't been any. Is there a problem or is it just that everybody is very busy?
Thanks, Peter Snowdon

--

	Jeff LaCoursiere STRATUSTALK, INC. / CTO Phone: +1 703.496.4990 x108 Mobile: +1 815.546.6599 Email: jeff@... Website: Address: One Freedom Square 13th Floor Reston, VA 20190
	? ? ?

开云体育

I found a video showing how to change out the bearing insert in the flange housings that Egbert suggested.? Now I see how it all goes together and can transfers axial loads.??? It all makes sense now.?


Here's a short video with a fellow describing a 4-bolt version of these bearings.


Of note is the detail of the self aligning nature of the bearings (at about the 40 second mark).?? This makes these bearings great for an installation where the mounting is not properly square to the shaft - within 3 or 5 degrees I think.

On a setup with a toothed belt reduction gear like I am planning (Which is equivalent to Thunderstruck in configuration) I think this may not work.? If the shaft goes off axis as the bearing allows it to do it will make the driven toothed belt pulley tilt out of alignment with the motor pulley.? That will be a problem for the belt.? I think rigid alignment between the pulleys of the toothed belt reduction drive is important.? Otherwise the belt may walk off the pulley or if it is a pulley with a lip? at the rim it will start to chew up the belt at the edge.?? It seems like any configuration that lets the shaft with the toothed belt pulley go off axis is a problem.? And having that freedom to go off axis means getting the reduction gear assembly aligned to the prop shaft while at the same time keeping the toothed belt gear pulleys in alignment will be more difficult.?? Seems to me the toothed belt pulleys need to be rigidly mounted which means the thrust bearing cannot have this spherical freedom or movement even if it is slight.?

Having another point where the shaft is supported radially would solve that problem?? Maybe the cutlass bearing provides that support.? But that's a bit flexible.? But that doesn't address the alignment difficulty to the prop shaft created by the freedom of the bearing to rotate spherically in the housing.? Seems to me if you want a system that is tolerant of axial misalignment that has to happen at the coupling between the prop shaft and the drive output.??


This is also interesting (at 1.5x speed) with regard to choosing bearings for reliability in axial and radial load:?

I am not an engineer or an engineering student but I learned a couple things from it.?


Thanks,

Dan Pfeiffer

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Carsten,

You suggested this very good thread from boatdesign.net:

In that comment Mike Johns said this:
-----
It would be nice to find a commercial bearing housing for two
tapered roller bearings and seals. But there are only the high
end marketed products mentioned before and they are
probably not much better than the spherical roller bearing.
-----

Seems to me Mike Johns is implying a housing with two tapered roller bearings would be what he would like to use.? ZF uses tapered roller bearings in their small boat transmissions (e.g. ZF 25).

Question:
Isn't the trailer hub a housing for two tapered roller bearings and seals???

I tried to track down Mike Johns to ask him if he had thoughts about a trailer hub like this.? No luck though.? He has not been on the boatdsesign list since last year.? But holding the hub in my hands it seems like a quite robust bit of gear.? Easily as robust as the Walter V-drive my boat came with.? However I do wish the bearings in the hub were the same size and the shaft to fit them could be more like 30 or 35mm.? It could with a larger hub but then you have to start with an even larger blank for the shaft.?

Also, an issue with any of these bearings is a housing to keep the lubricant in.? What do you think of a sealed bearing in this application??? Are there sealed versions of the spherical roller bearing you like?? I can't find any and I would suspect no because a seal would not be conducive to the spherical motion of the bearing.?? So then a housing is need with seals.?? And to handle all those torsion forces and misalignments you speak of what sort of seals would be needed??

Here is a sealed double roller angular contact ball bearing:



This is of the same type used in my Walter v-drive for the thrust bearing but larger and in a sealed version.? It should be more than adequate for the load (as the smaller one in the v-drive has been for 43 years).? Would this be a possible choice if a suitable housing could be found or made??? The bearing is rated for 6000 rpm and would see no more than 1000 in a small boat application so that seems like light duty for RPM.?

For these very nice bearings that Egbert found, how are they retained in the housing??? It looks like just a press fit with no shoulder on either side and I don't see any set screws on the housing (just on the bearing to hold to the shaft).? So what transfers the axial load to the housing?? The bearing may be rated for the load but the load has to be transferred to the housing somehow?? I also see these housings in a 3-bolt of 4-bolt flange which might be a more robust choice.?? Also is stainless as pointless as that may be.



Thanks,

Dan Pfeiffer

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