T-Pain Is On A Boat: Re: [Electric Boats] AN ARBY

Wednesday, April 17, 2013

Re: [Electric Boats] AN ARBY

An Arby? I love it.

I also like the watt/knot

SV Green

144 VDC

5.1 tons
Kevin J Shepherd

On 2013-04-15, at 7:40 AM, dan walker <dsailormon@yahoo.com> wrote:

I LIKE THAT. an arby=1watt hour per pound. i need to lose weight for more range. fewer "arbys" and big macs
dan

From: Roger L <rogerlov@ix.netcom.com>
To: electricboats@yahoogroups.com
Sent: Monday, April 15, 2013 10:12 AM
Subject: Re: [Electric Boats] Re: Proper battery capacity

I wonder how our electric canoe would stack up? It's at the opposite end of the displacement scale from Arby's example.

We've just spent two months of using the boat most days in a variety or bay and river conditions in Florida. So we have a decent data set.

I'll post some pictures of the rig on the Forum site under the heading "An Electric Canoe" .

On a average day we tend to travel 3 to 5 hrs per afternoon using about quarter throttle (100 watts) which yields 3 knots - which is about half of our top speed.

The actual displacement of boat and load - including people and batteries - is very close to 400 lbs.

Our max battery capacity is 16 amp hrs. at 29 volts, although we rarely use it all. Calling it 400 watt*hrs would be close to max.

Well I'll be dipped. .... ....... Arby, your rule of thumb is right on even for a craft like ours so very far removed from the intended use. Just like your rule of thumb predicts, we have a power to weight ration of 1 watt*hr per pound.

Or one "Arby".

     Roger L.

----- Original Message -----

From: Tom

To: electricboats@yahoogroups.com

Sent: Monday, April 15, 2013 1:59 AM

Subject: [Electric Boats] Re: Proper battery capacity

Hi Arby,

I would think that the energy storage would vary quite widely, independently from displacement.

I can visualize a large range of kWh installed in any given hull, depending on range requirements, what charging sources are available, and how much battery weight, cost, and space is allowed.

For what it's worth, I have 8.6kWh installed on a boat that displaces 3100 lbs. For most of my trips that is plenty. Sometimes, like on my all-day run today, 12-16kWh would be nice.

-Tom

--- In electricboats@yahoogroups.com, Arby Bernt <arbybernt@...> wrote:
>
> We have a nice rule of thumb for power, about 1kw per ton of displacement.
> I'd like to propose a battery standard.
> How does 1wH per pound of displacement work?
> Our test boat, a 7000lb Ericson 27 has 9600wH, and is never worked. A 13000lb Rawson 30 I converted has 12kwH of power, and it gets worked.
> Other Systems..?
>
> Arby Bernt
> Advanced Marine Electric Propulsion.
>

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