T-Pain Is On A Boat: [Electric Boats] Re: Proper battery capacity

Thursday, April 18, 2013

[Electric Boats] Re: Proper battery capacity

It is an Arby Junior - about 1/2 watt-hour per pound of displacement or one KWH per ton.

--- In electricboats@yahoogroups.com, "matwete@comcast.net" <matwete@...> wrote:
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> How many Arbys is that? :-)
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> From my HTC Sensation 4G on T-Mobile. The first nationwide 4G network
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> ----- Reply message -----
> From: "Steve" <sstuller@...>
> To: <electricboats@yahoogroups.com>
> Subject: [Electric Boats] Re: Proper battery capacity
> Date: Wed, Apr 17, 2013 6:17 am
> Another guide for figuring out your battery capacity is to use your average boat speed. Assume three knots then given a six hour day and borrowing Eric's data for a power input of 100 watts per ton of displacement (at three knots) and 50% DOD then you have 600 WH/day/ton/.5 or 1.2 KWH of battery capacity per ton. This is the capacity of a 100 AH 12 volt battery or one battery per ton. Using Eric's boat as an example you would have 1.2 KWH/battery times five tons or six KWH of battery capacity. That's reasonably close to his actual consumption. Thanks. Steve S.
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> --- In electricboats@yahoogroups.com, "Eric" <ewdysar@> wrote:
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> > Hi Arby,
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> > That seems like a good starting place. I am running an 8kWh lithium pack in my 10,200 lb ketch and I rarely get down to 50% of my usable capacity (I use 80% of rated capacity for my usable capacity) during my typical day sails and weekends of coastal cruising. To get the same range from other battery types at 4kts, I would need 11kWh of AGM or 13kWh of flooded cells. So averaged out, that's pretty close to 1 Wh per lb like you suggest.
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> > Of course, special use cases would require different size banks. But I think that typical recreation sailboaters will do fine with your rule.
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> > Fair winds,
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> > Eric
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> > Marina del Rey, CA
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> > --- In electricboats@yahoogroups.com, Arby Bernt <arbybernt@> wrote:
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> > >
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> > > We have a nice rule of thumb for power, about 1kw per ton of displacement.
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> > > I'd like to propose a battery standard.
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> > > How does 1wH per pound of displacement work?
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> > > 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.
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> > > Other Systems..?
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> > >
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> > > Arby Bernt
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> > > Advanced Marine Electric Propulsion.
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> > >
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