T-Pain Is On A Boat: Re: [Electric Boats] Re: new system from scratch, am i on the right track please? [1 Attachment]

Monday, April 30, 2012

Re: [Electric Boats] Re: new system from scratch, am i on the right track please? [1 Attachment]

[Attachment(s) from Julian Webb included below]

Hi Eric

- I didn't give any boat details to "cloud the waters" in case my guesstimate of system was not right.

- Thanks for the input and yes I'm happy to pass on what works for me and what doesn't.

- I attach a pic of the boat. Her details are:

LOA = 10.3 M

Beam = 3.8 M

Draught = 1.2 M

Weight = 11.5 T

Hull speed = 7 knots (guessed by diesel usage calcs over 2 years by previous owner)

Hull = Displacement

Construction = Steel

Drives = 2 x 23" props driven by 50 HP Fordson D type diesels 2:1 reduced

Built = As Thames tender 1965

- I was hoping 2 x Aquamot (MA110) 11kW (48 VDC to controllers) AC motors belt reduced 2:1 to give 650 RPM at 144 Nm to each prop shaft would give me a good 6-7 knot hull speed. http://www.aquamot.at/en/product-range/drives/shaft-drive.html

- Apart from the twice a year English Channel, Mediterranean coast hopping for a month, it will spend most of it's life doing 4 knots on the French and German canals, which is why I'm happy to swap higher cruising speed for the cheap/free electric drive lower speed for the canals.

- I was hoping to get a PolarDC Marine 20 kW 48 VDC genset but they're so busy they can do no more in 4-5 days than send an auto response apologising for being so busy.

- Do you know of anybody else? Or do I have to make my own with a Yanmar/Kubota diesel and proven Delco etc generators with the necessary off-the-shelf controller(s)?

- Batteries are a conundrum. Whether to spring for Lithium-Iron-Phosphate or just half decent semi/traction ones?

- All experience and suggestions gratefully received.

Cheers, Jules

On 30 April 2012 19:57, Eric <ewdysar@yahoo.com> wrote:

Hi julesproto (?)

Yes, you sound like you're on the right track. A DC generator is more efficient for charging and driving a DC system. Regular battery charger for shore charging, when available. DC-DC convertor for low voltage house loads and a DC-AC inverter for "shore type" appliances. Hot water from the generator with propane or electric boost seems reasonable.

You don't give any indication of the type or size of the boat that you're working with, so suggestions about your battery bank size, voltage or chemistry or any other component specifications are not really possible.

Hopefully, if you get any good information here, you'll "pay it forward" by sharing details of your success when your project is up and running. Many people don't share what works, which is why your research results have been "... so eclectic, contradictory, disjointed or just plain rare...". Much of the information on the inter-web comes from people trying to sell you something, so a decent percentage of that is exaggerated at best, and boldfaced lies at worst. This group's members have considerable electric conversion experience, and we really try to help anybody who is reasonably polite. Most of us have nothing to gain but happier fellow electric boat owners and better electric boat conversions out in the world.

Fair winds,
Eric
1964 Bermuda 30, 5.5kW Propulsion Marine drive, 8kWh Lithium batteries
Marina del Rey, CA

"If you're not part of the solution, you may be part of the problem"

--- In electricboats@yahoogroups.com, "julesproto" <julian.proto@...> wrote:
>
> pardon any lack of protocol but this is the first time i have ever joined a forum seeking practical advice.
> usually it's by going somewhere to get it first hand, trawling the net for data/spec sheets or off to a library, BUT what info is out there on electric drive systems is so eclectic, contradictory, disjointed or just plain rare that i admit although i'm pretty sure i am on the right track, i would very much appreciate and be grateful for any help or experience anyone can share, and i'm happy to return the favour.
>
> it seems better to use a diesel generator to produce DC with a large enough capacity to power the electric drive motor(s) directly for the times when i need cruising speed.
> this will let me get away from the "usual" AC output genset that has to be converted to DC before being sent to the motor controllers(s).
>
> add a battery bank of the same DC voltage as the generators output and the motor controllers input.
>
> add a single phase battery charger for shore power top up.
>
> add a 230 VAC output inverter to run the onboard appliances.
>
> if i can get my hot water from the genset that about finishes the system?
>
> if i am heading in the right direction, i will bore you with the boat details, but i thought i would get the theory right before moving on to the practice.
>
> thanking everyone in advance
>