PSC34 electric propulsion conversion progress

[KTP]

I thought I would start a new thread about our ongoing conversion of a 1989 Pacific Seacraft 34 sailboat to electric propulsion.

I know we will/have a lot of flak for doing this but I really should have gotten a brand new boat if I wanted something this small. It is literally impossible for me to get access to areas of the diesel engine or the steering mechanism buried in the stern behind the engine. When we pulled out the engine (the motor mounts fell apart into many rusted pieces) it was a joy to stretch out and work on the rudder stuffing box and replace the aluminum quadrant (which had to be cut off) Now the boat has a brand new Edson quadrant and the rudder stuffing repacked.

We have installed a 12kW brushless motor with Sevcon gen4 controller and a initial battery bank of eight Lifeline 12V 125AH AGM batteries. We were able to fit four under the settee seats both port and starboard. This gives us 48V at 250AH (obviously less than that real world usable). We have plans to perhaps add eight more of the Trojan Trillium 92AH lithiums when they come out next year if the price is right. Eventually I would love to have something like 40kW in batteries and still be less than the weight of the previous engine and fuel tank.

Because of some gales and small craft advisories every day, we have not yet been out on the water with this setup (just got it installed a few days ago) but tests in our slip at up to 150 amps into the controller show some serious thrust. The motor spins at 0.7 amps too, so I must have gotten the alignment decent. Really need to clean the prop but that is probably a job. Stupid barnacles.

Anyway here are a couple of shots of before and after in the engine bay.

[StuM]

What's your anticipated use of propulsion?
What's your energy replenishment source?

[KTP]

Originally Posted by StuM

What's your anticipated use of propulsion?
What's your energy replenishment source?

When we are just tooling around our local marina, probably will just be recharging with shore power. We installed a Magnum 48V inverter/charger which can charge at 60amps with 30amp shore power.

We plan on having a lot of solar, some of which would only be installed on calm or when on the hook for several days. I want to have 400 watts on each side hanging on the lifelines which is quick to connect and to stow plus about 600 watts on the bimini + dodger. So at any given time, should be getting a few hundred watts from something.

A good wind generator

Maybe something from regen (maybe...will have to see if that is even viable)



We mostly want to use propulsion to enter and exit the marina, and to motor sail on light air days. When you have just 10 amps going to the motor it produces a noticeable amount of thrust but is silent....like 5 feet from the boat I can't hear anything. Should make for some interesting sailing on those days when the sun is out and the wind is 5mph. Probably could go for 20+ hours like that on a 20kwh bank and still be above 50%.

[a64pilot]

Look forward to seeing how well it works.
My prediction is you will change they way you sail / travel to accommodate the EP, unless of course you hated the noisy, stinky motor and it grated on you to run it, then you likely have already changed.
Nothing wrong with that, a few do without any form of propulsion other than sail.

[john61ct]

Please let me know if this is an unwelcome derail.

Would it be (have been) possible to add a physically small diesel genset capable of powering that motor at WOT without pulling down the bank?

[LoudMusic]

Reading about these projects excites me for the future. I'm looking forward to usage updates from you and others.

[a64pilot]

Originally Posted by john61ct

Please let me know if this is an unwelcome derail.

Would it be (have been) possible to add a physically small diesel genset capable of powering that motor at WOT without pulling down the bank?

It is a 12KW motor.
Now I admit I’m not electrical guru, but a Watt should be a Watt, so then you would need a 12KW generator ignoring any inefficiencies of power conversion etc.
12KW is a big generator, expensive and heavy, likely no real need to go that big though? Do you need to sustain continuous full thrust?

However I see a Honda in his future is he is going very far from his dock.

[misfits]

I added 2 100 watt 24 volt panels on the rails using rail clamps
They can be folded or removed if need be. On my boat anything larger would require them to be removed to go sailing, traveler's on the stern & the mainsheet would hit them.

[mwmsea]

Looks great. I believe as EP progresses that many vessels will adopt it.

Do you mind sharing what brand of EP you chose and why?

Thank you.

Mike

[KTP]

Yes we are early retired and plan to sail and use the EP sparingly, even if that means waiting for advantage on tides and waiting out the weather. There is nothing I like better than the quiet of sailing. I really hate the sound of the diesel droning on and on. The boat also smells SO much better now after a couple of months with the engine, fuel tank and dirty hoses, filters, etc. removed. It like doesn't smell like a boat, more like you just walked into a new house. It has to be somewhat healthier not breathing in all the diesel fumes too.

That being said, we do plan on taking a Honda generator 2200i for initial testing when we start going on longer trips. Eventually I hope to ditch that but I want the extra capacity until we can either get a huge battery bank or start to trust our solar, wind, and sailing skills. I figure the 2200i can produce about 1800 watts continuous (2200 watts for 30 min) and is light, fairly quiet and easy to stow. I figure you would get maybe 3 to 4 hours of run time on a gallon of gas so 10 gallons should hold 50 to 70kWh. With the conversion efficiency of our 48 volt Magnum inverter/charger rated at 85%, figure you could put somewhere around 40kWh to 60kWh back into the battery bank using the 10 gallons of gasoline.

It remains to be seen/tested what wattage to the motor will produce a certain speed in different conditions. Just from some research I have a ballpark guess that 500 watts to the motor in dead calm conditions will move the boat around 2kt (and likely do nothing much at all in heavy wind or seas). 10kW should get the boat moving in most conditions but won't be sustainable for long. Maybe 2 hours max once we get our battery bank finalized, then we would need to find a safe cove, start sailing, or re-think why we bought a sailboat in the first place. On a sunny summer day with winds 0 to 5kt and a light ripple to the flat water, which is quite typical in the Puget Sound, I expect 2kW into the motor to deliver 4kt speed, giving us a range on those days of 40nm with our 20kWh battery bank. I might be off by a large amount here, but that is my guesstimate.

[john61ct]

Originally Posted by a64pilot

12KW is a big generator, expensive and heavy, likely no real need to go that big though? Do you need to sustain continuous full thrust?

My idea is to be able to fully power the motor WOT from the genset. If a big enough genset won't fit on the boat, then go to a smaller motor.

I believe on this type of boat, weight is not as big an obstacle as volume, size of the genset + motor fitting into the space designed for a direct-drive diesel.

[KTP]

Originally Posted by mwmsea

Looks great. I believe as EP progresses that many vessels will adopt it.

Do you mind sharing what brand of EP you chose and why?

Thank you.

Mike

Sure. We went with one of the Thunderstruck sailing EP conversion kits, which included a water cooled (closed loop) brushless motor, a Sevcon Gen4 450 amp 48V motor controller (really a nicely built controller!) and a 3:1 timing gear reduction/thrust bearing/shaft coupler unit. We chose this because it was pretty inexpensive and allowed DIY and some ability to customize things. There are other systems that are more bolt in place like the sailordrive? but are somewhat more expensive and I was also unsure of how they would mount where we wanted them mounted. The nice thing about this kit is we can carry a spare controller and even a spare motor because they are just not that expensive or heavy/bulky. Not many sailors can claim to carry a spare diesel (ok maybe CATs can).

We went with 3:1 reduction instead of 2:1 because I am thinking of getting a larger prop eventually. It is more efficient to turn a larger prop (but this does create more drag...but you can always have the motor going with a couple of input amps to overcome this drag while sailing).

[Montanan]

Nice integration of the motor. ePropulsion being very suitable for day sailing and overnight / short distance cruising what with its low cost of operation, minimal maintenance, quietness, lack of emissions, etc. But obviously not viable for truly long distance motoring without the rechargeability of an onboard genny.

What kind of 12kW motor and VFD have you installed? What is its weight?

The motor's torque profile likely should suit the use of a low speed, wide diameter, high pitch propeller which will make for much more efficient propulsion than a standard propeller, albeit clearance of course being a limiting factor. Traditional sailboats being displacement vessels it is all about efficiency of torque, not peaking velocity.

Changing over to a Tohatsu SailPro 4 horsepower outboard motor from a 9.9 horsepower motor on one of my sailboats was remarkable. The much smaller power, yet larger diameter, higher pitch propeller provides greater cruising speed while operating at just one quarter throttle setting than did the standard outboard operating near full throttle.

[Kalinowski]

Welcome to the other side. We converted our Pearson 424 ketch to electric when the diesel was close to the grave. No regrets. We live aboard in a marina, so topping off is easy. We only use the motor when moving in/out of the slip. Battery/solar tech is evolving at a rapid rate, so we'll be ready when improvement is cheaper and necessary.

[grantmc]

Wonderful to see your project OP and thank you most sincerely for sharing. I actually think most boats where I live would easily manage on an electric motor. Most just use the motor to exit and enter their marina.

Electric has so many obvious advantages, the most obvious is that only a single hole in the hull is needed for the propeller shaft.

Very very keen to hear more about your experience.