Electric Drive: Who uses it?

[john61ct]

Original inventor of TPPL AGM is Enersys, both Odyssey brand and Optima (red top) which they sold to JCI.

Northstar founded by ex Enersys employees, great products too.

Concorde/Lifeline is the other top maker in NA, came out of the Aerospace market.

[petit bateau]

Originally Posted by a64pilot

There have been a couple of those built, one had a regular windmill, and another I have seen pictures of had a horizontal windmill, which seemed to at least look more practical.
Apparently neither Sail as well as an old fashioned sail boat though.
https://www.treehugger.com/renewable...-the-wind.html

The 'horizontal' ones you are referring to are Flettner rotors.

(e.g. https://en.wikipedia.org/wiki/Flettner_rotor )

[Capt. Arnaud]

Ok it is half a year after the last post but to answer the original question:
Electric Drive: Who uses it?
I do.

Why? Because I only have to motor in and out of very small harbors where the boat can't tag, the rest I sail, so for me using a diesel engine just for about 5 min each time is very bad for the engine.
I actually use the electric drive a lot less than 5 min, just a burst to get out the slip, and one to turn before drifting out under the staysail. In total maybe 1 minute.
Motoring in takes still 5 minutes of use. (against the wind, no room to tag)
The other problem here is that they use floating dock lines on buoys for the "Mediterranean mooring style" so the harbor is literally a spaghetti bowl of it.
With a diesel and a cold gearbox even in neutral the prop can still turn, on the electric it's not unless you go too fast ofcourse. So sometimes we slide over some lines with less chance to get caught.
But the main reason is the capability to regenerate during sailing.
I know that a lot of people are against the idea because they don't want to lose speed for a little bit of power but by calculating everything and optimizing the system to regenerate rather than being able to push the boat to hullspeed I was positively surprised with the results.
To push a boat it seems to be better to connect the motor directly 1/1.
But to generate it is better to have a reduction so that for every prop turn your motor turns several turns.
A gearbox like in a car with different gears could sound as a good solution but I think that the friction produced by it will be too great to be effective and I prefer a system without having to do oil changes or the chance of an oil leak and having to have cans with oil onboard as before.
So I made a pulley reduction of 1/3 what seems to work well to generate and have still enough speed to push up the headwind in the harbor, it actually gives more torque on the propshaft so my next propeller will be a 4 blade to make the system more efficient at lower revs.
Until now we were unable to measure a significant speed difference while sailing freewheeling or charging, there has to be a difference for sure but on my boat not noticable. I think this is because my electric motor is only a 7,5KW motor for a boat of 28t on paper it is not a lot at all to push it but still better than rowing ;-)

[hzcruiser]

Originally Posted by Capt. Arnaud

Ok it is half a year after the last post but to answer the original question:
Electric Drive: Who uses it?
I do.
[...]
So I made a pulley reduction of 1/3 what seems to work well to generate and have still enough speed to push up the headwind in the harbor, it actually gives more torque on the propshaft so my next propeller will be a 4 blade to make the system more efficient at lower revs.
[...]

That sound like a great solution! Are you using a chain or belt for the pulleys ? That reduction should work fine since electric motors deliver torque over a wide range of rpms. So when pushing the motor spins three times faster with the pulley system as before, or the prop spins at one third at the same motor rpms. For a pretty heavy vessel, this really is what you want anyway.
I now wonder what battery voltage/currents you use to drive the 7.5kW motor and how you charge the batts?

[Capt. Arnaud]

Originally Posted by hzcruiser

That sound like a great solution! Are you using a chain or belt for the pulleys ? That reduction should work fine since electric motors deliver torque over a wide range of rpms. So when pushing the motor spins three times faster with the pulley system as before, or the prop spins at one third at the same motor rpms. For a pretty heavy vessel, this really is what you want anyway.
I now wonder what battery voltage/currents you use to drive the 7.5kW motor and how you charge the batts?

My system works on 72V
In the harbor I have a charger charging the bank at 72V but at sea the only way is by regeneration.
Above 5kn I get 20amps at 72V= more than 1Kw
I also have a DC-DC converter to charge the house bank by regen.
I use a double V belt (available everywhere in the world)

[hzcruiser]

Originally Posted by Capt. Arnaud

My system works on 72V
In the harbor I have a charger charging the bank at 72V but at sea the only way is by regeneration.
Above 5kn I get 20amps at 72V= more than 1Kw
I also have a DC-DC converter to charge the house bank by regen.
I use a double V belt (available everywhere in the world)

Thanks Arnaud!
72V makes sense, in order to keep the currents more manageable, at around 100A. 1 kW is a very good regen rate as well!
Sounds like a very good system! The main issue some might have with this could be the dedication of some batts to propulsion only and then you still need the house batts as before.
But since there is no 12V DC to 220V AC inverter available in the power range of 7kW this might be the best we can do ATM. There are 48V DC inverters in the 10kW range though. In which case one would need to step that back down to 12V DC for the small consumers. Either way I guess you got a good combination there.

[KTP]

Originally Posted by hzcruiser

Thanks Arnaud!
72V makes sense, in order to keep the currents more manageable, at around 100A. 1 kW is a very good regen rate as well!
Sounds like a very good system! The main issue some might have with this could be the dedication of some batts to propulsion only and then you still need the house batts as before.
But since there is no 12V DC to 220V AC inverter available in the power range of 7kW this might be the best we can do ATM. There are 48V DC inverters in the 10kW range though. In which case one would need to step that back down to 12V DC for the small consumers. Either way I guess you got a good combination there.

We also installed an electric drive but have not been able to take the boat out yet due to constant gale force winds (and the call of snowmobiles!). We use a 48 volt system charged by a Magnum MS4048 inverter/charger which can charge at 60 amps or provide over 4kW of AC from the bank for things like coffee makers or whatever. For 12V appliances we installed a compact efficient DC-DC converter which converts the 48V to 12V at up to 50 amps. It is around 92% efficient.

I love hearing about the regen possibilities as we do have a 3:1 reduction but we may need to change our prop for better regen. We just have had no chance to test out the system yet except for thrust at dock (plenty of thrust there though!).

Just removing the smell of the old engine and fuel tank/hoses/filters from the boat in the past 3 months has made the system worthwhile in my book. Plus the extra room we have now in the engine area!