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Electric repower ideas

11K views 50 replies 15 participants last post by  Captain Canuck 
#1 ·
Hi Guys,

My wife and I have been researching how to repower our boat. This is for a number of reasons.

1) I'm an engineer.
2) We both hate the smell of diesel.
3) We are Chesapeake Bay sailors, so we only need the motor to get in and out of the marina.
4) We like to be eco friendly.
5) Diesel prices aren't ever going to go down, and solar power and regen is free.
6) We like the idea of a maintenance-free motor.
7) Net weight loss (with LiFePo4 or Lithium Ion batteries)

We have a 1987 Hunter 28.5. The 16HP Yanmar Diesel is nice enough, but for the Chesapeake bay it's probably overkill, and I can sell it to help finance the new system.

Here's the setup as I have envisioned it so far:

5 or 10kW DC electric motor w/regen
5 or 10kW DC electric motor controller
Lithium Battery Charge controller
6kWh of Lithium EV batteries
DC to DC converter for house current (negating the need for house batteries altogether)
200W-ish single Solar Panel to top off batteries when not in use (200W of solar should generate 1/2 to 1 kWh per day during the boating season). If my calculations are correct, I won't even need shore power between the regen and the solar panel to keep the batteries charged.
I'm looking at a total weight of about 200lbs, including solar panel, motor, controller, batteries, etc.

If my calculations are correct, I'll only need about 2kW of draw to push the Hunter at no-wake speed to get out of the marina, giving me about 8-10x the power I need to get in and out on any given day, assuming no regen from sailing and no solar.

Advantages:

No maintenance
Motor, controller and belt MTBF exceeds expected boat lifetime
Quiet
Instant power (or reverse power) at any time, in any weather
Fuel is free, as long as I don't use shore power
Electric system is considerably lighter overall (Lithium batteries are ~1/6th the weight of lead-acid)

Disadvantages

Limited battery capacity (though this will only get better as batteries advance, and I can add more later)
Refueling is slow (though if I'm only sailing on weekends, this is irrelevant)
A lot of work to retrofit, but not difficult work, just time consuming. Getting the diesel and tank out is going to be the hardest part.

Anything I've missed?
 
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#2 ·
RE; #2 Fix the diesel leak? I never smell in on my old tub with it's new fuel system.
RE; #3 Do you row the boat in July and August?
RE; #7 fire danger with Lithium Ion batteries?

add; #8 we have unlimited funds
add; #9 how much and how large copper cables, terminals, etc
 
#4 ·
#2: Tried that. It must be a very slow leak somewhere I can't find. It's not fast enough to be obvious, just enough to smell.
#3: I have no idea what you mean by this.
#7: Nope. EV L-Ion batteries have a discharge rate far higher than what I'll need, even at WOT. I don't expect them to ever overheat, but I'll probably put a temperature monitor on them anyway just in case.
#8: Heh. 6kWh of EV batteries is currently about $1400, and almost everything else will be covered by selling the old diesel. It's the labor that kills you on projects like this, but I can do all that myself.
#9: From the batteries to the controller (which is attached to the motor mount) Probably #000. Once I compute the actual load and distance required I'll go one step up from recommended, because overkill is underrated. Same reason I use 20A Nomex in my house for the 15A outlets.

Good questions though. I appreciate the feedback, I might have missed something.
 
#3 ·
I don't see any glaring issues. You seem to be reasonable about expected range and capability which is normally the major problem with these threads.

I would suggest getting a small 2kw honda generator for those times when you need to deliver the boat somewhere, but otherwise it looks reasonable.
 
#5 ·
I don't see any glaring issues. You seem to be reasonable about expected range and capability which is normally the major problem with these threads.

I would suggest getting a small 2kw honda generator for those times when you need to deliver the boat somewhere, but otherwise it looks reasonable.
Point taken about the honda generator. After the system is installed, if I find I'm using more power than I thought, I'll probably get one. Theory can be a lot different than reality...
 
#6 ·
#7 ·
July August are dead air months not to mention heat and the need for some people to get out of the baking sun rather then sit and wait..and wait... for a breath of air.

I'd dig deeper for the fuel smell/leak. Tank could have seepage in the bottom.

It all seems like allot of work and effort just to get in/out of marinas when you have a perfectly good engine.
 
#10 ·
July August are dead air months not to mention heat and the need for some people to get out of the baking sun rather then sit and wait..and wait... for a breath of air.

I'd dig deeper for the fuel smell/leak. Tank could have seepage in the bottom.

It all seems like allot of work and effort just to get in/out of marinas when you have a perfectly good engine.
Point taken in regards to the dead air months. We'll just have to see how that works out after our first season in a pure electric.

I have a fair bit of experience with ICEs in general, less with diesels, but it could be a small crack in the fuel line somewhere that's leaking just enough to let it smell. $5 says I'll find it when I pull the engine out and it will be somewhere obscure and/or damn near impossible to get to.

In short, other than fuel supply, an electric system is superior in every single way. It's cheaper, easier to diagnose, more powerful pound for pound, the fuel is cheaper no matter what the source, there's no maintenance, etc. Once battery capacity or a small, portable high energy power source is developed, diesels are toast, save for "vintage" folks. I'd prefer to be on the leading edge than the trailing edge.
 
#19 ·
theres a guy at my yacht club that purchased a brand new catamaran with 2 electric powered motor for propulsion in and out of the harbour. lets jsut say after 2 year i never seen anyone rip something out so quick. It may look good on paper but when it comes together you might have some issues. I would defiantly look at one of those new inverter generators that creaats enough power to run the electric motor because it will never charge your battery bank quick enough. have it run so you can switch it from charge to direct power. you can actually moun them in your engine compartment and weld up an exhaust to vent it. If your looking for wire. Consider using welding wire. It comes in every size and is pure copper.
 
#27 ·
theres a guy at my yacht club that purchased a brand new catamaran with 2 electric powered motor for propulsion in and out of the harbour. lets jsut say after 2 year i never seen anyone rip something out so quick.
LOL!

I've been talking with a guy over the last couple of weeks regarding moving his newly-purchased Nonsuch 33 from Annapolis to NJ… The boat is electrically-powered, same deal, "just enough to get in and out of the marina"…

Lots of consultation with the folks at Annapolis Hybrid Power, the plan is to install a DC generator to charge the batteries. Problem is, the recommended generator cannot be delivered before January, or thereabouts, and the guy wants his new baby back home before then, naturally…

So, after calculating all the costs of the single portable generator capable of powering the boat @ 3 knots, or the dual parallel setup that would likely push the boat @ 5 or more, I got the phone call a few hours ago…

They've decided to truck the thing, instead… LOL!

Can't say I blame him, that might have turned out to be a rather pricey little delivery… On the other hand, might have been a nice little sail, you never know...

:)
 
#20 ·
Canuck,

You need to redo your consumption numbers. The correct comparison between a diesel burning .4gallons/hr is about 6.7kw, not 2 (the actual number is 18hp/gallon). This is why renewables for propulsion power just don't work. Moving a multi ton vessel around just burns more power than any reasonable renewable setup can produce.

This is why it's critical when considering an electric setup that usage patterns change. You have to accept that you will go slower, with less range, and have almost no reserve power. So long as you are realistic about this it is fine, but fudge these numbers and you will be greatly disappointed.


As an addendum, there is no battery technology on the market, or even in laboratories today that come close to resolving this dilemma. The best laboratory battery I know of has an energy density of about 5% that of diesel fuel. This would still only provide a fraction of the power available most boats consider minimal. At the rate battery technology is going a realistic timeframe is probably more like 50 years (absent a real breakthrough).
 
#30 ·
Out in my real world with state of the art electric fork-trucks and riding pallet jacks the maintenance people are plenty busy and the battery chargers on the big ones are on 50 amp 3 phase circuits
 
#31 ·
^^^^bingo...

Im back in the states, soon to get a boat... Im all in the forklift conversion crowd that has been around for a long time now in the small sedan car conversion industry...

forklift dc motor, reostat...batteries

golf cart conversions are even cheaper, however those motors are more stop and go design and need cooling of some sort.

doesnt get any simpler than that and much cheaper than a complicated ac kit which has the unbenefit of being complicated to replace(especiaally fried controllers and chargers)

however there are some nice kits from electricmotorsport and other places that have awesome ac kits with regen.

my dream still for my future cruising boat despite the range defficiencies is to use 48v solar with portable gen backup, stepped down to house 12v.

48v for the electric inboard and 12house stepped for everything else...

no ac anywhere in the boat, shoreopower or otherwise

I truly hate ac heavy boats...that rely on conversion and inverters more than direct sources, i.e wind, solar....engine...etc...

anywhoo

time will tell
 
#32 ·
If you get a bigger DC motor than you need and run it at less than it's rating, you'll never have to worry about heat.

I like the Electric Yacht kits here: DIY Kits | Electric Yacht
I met the guys who sell their stuff here at the Annapolis boat show. They were very knowledgeable, and their primary engineer converted his own boat. When the time comes to do my own conversion, I'll probably end up using one of their kits to do it.

I'd also like my boat to be all DC, with a shore power charger if I need it. But I'm not doing a liveaboard yet, I'm still just a weekender. That might change when I move up to my next boat, probably a cat...
 
#36 ·
My Club has done three conversions.

I'm now a 6500 lb. sloop that is the lowest end conversion. 7kw, belted, 48vdc, and lead acid. A floating golf cart. It demands being sailed.

A friend went with a California package deal, lithium, AC, in an older Dufour 30
And lastly, the most important Tesla type conversion is by the Laser designer Ian Bruce. His Bruce 22 has 170hp, AC only, and is a classic Chris Craft design,
selling for about the same price as the Tesla S.

Oh by the way, since the Royals are in New York, allow me to mention, that last year, Prince Phillip sent us a little note, congratulating the Club for a 125 years of dedication to the sport of sailing.
 
#37 ·
..... the most important Tesla type conversion is by the Laser designer Ian Bruce. His Bruce 22 has 170hp, AC only, and is a classic Chris Craft design,
selling for about the same price as the Tesla S.
The Laser was designed by Bruce Kirby. It was his first paying design and he went on to design all many types of sailboats from San Juan's to 12 meters to sharpies, as well as Canada I and II. I don't believe he designed any powerboats.

Laser (dinghy) - Wikipedia, the free encyclopedia

Sailboat designs of Bruce Kirby by year
 
#39 ·
He may be called the father of the Laser and he was involved in its rigging, but Bruce Kirby received the royalty cheques. See Professional Boatbuilder issue #142 April/May 2013, page 62 for detailed article on Bruce Kirby.

A single blade propeller?:laugher
 
#41 ·
Hi Captain Canuck,

You are headed in the right direction with your plans. If you are planning to use lithium it's probably a good idea to use a BMS (battery management system) so you don't run the batteries down too low or charge them too high. When I repowered my 1976 Ericson 27 with electric I hoped the AGM batteries that I used would last 5 or 6 years. At that point I thought I would replace to batteries with lithium. I have yet to make the change (6 + years) but I'm in the process. I didn't see any mention of instruments (I may have missed it). A voltage reading for each battery (down below) and an ammeter/voltmeter at the helm are pretty much must-haves. It's amazing how a very small adjustment in throttle position can lower your current consumption and keep you moving at the same speed. Also the ammeter at the helm is critical for regeneration. I started a description of my system on the Ericson Yachts web site, I need to update it but it may be helpful Ep - Blogs - EY.o Information Exchange
 
#42 · (Edited)
mark you were one of the first conversions I read about

congrats on such a great system

and thanks

christian

ps what lithiums are you thinking about and what mods to your system would that entail?

how much % battery loss do you think you have endured over 6 plus years?
 
#43 ·
I'm posting up on this thread because of very little activity in the classified section. I have a complete 5 Kw Electric Yacht motor set up. Would be a good option for a 27 Catalina or smaller sailboat, replacing the Atomic 4.

Set up comes with everything you need to do the conversion. I'm selling the unit because I bought the boat with the electric already installed and an outboard too. I don't need both, and I do long trips vs short day sailing that require many hours of motoring. I do sail when I can, have enjoyed the electric for maneuvering in the harbor, zero maintenance, or just out for a day sail.
The Electric Yacht complete unit with 4 (100amp)batteries and charger would be $6000, asking 1/2 price, $3000 OBO. Unit is still operational in my sailboat.
I have complete description and pics here:
5.0 KW Inboard Electric Motor For Sailboat For Sale

Any help getting my set up to someone looking at doing a conversion would be appreciated.

Thanks
 
#46 ·
Hi Guys. I'm purchasing a hunter 29.5, so I'm going to have to rethink my repowering strategy. The good news is the Yanmar diesel in the boat is in pristine condition, so I should be able to sell it for more than enough to do the conversion. Once I have the boat in hand I can start planning out the conversion. I'll probably start once the season ends, I don't want to take away my family's time on our boat during good weather.
 
#49 ·
LiFePo4 batteries have not gone down in price recently - gone up as a matter of fact.

I can understand switching if the diesel is shot but to replace a good diesel with electric and get less range and resale makes no sense.

A well maintained diesel doesn't smell.
 
#51 ·
LiFePo4 batteries have not gone down in price recently - gone up as a matter of fact.

I can understand switching if the diesel is shot but to replace a good diesel with electric and get less range and resale makes no sense.

A well maintained diesel doesn't smell.
Funny, I haven't seen prices go up, and I monitor them pretty closely. Where are you sourcing your batteries? I'm generally seeing them for around $450-$500/kWh for the CALB Prismatics.
 
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