Keith,
Thanks for the information. The space for the additional 4 is believe it or not where the diesel tank use to be. I think you are exactly right on battery capacity and it really does need to be increased.
It was a 3 blade fixed prop. 17" x 17 pitch. We had purchased a couple used props from Minnies in Newport Beach to play with regen numbers.. The next one to try is a 16" x 19pitch.
We were encouraged by the regen numbers as well and I wish we had a little more wind because hull speed for this boat sits between 8-9 knots and I have had it up to as high as 13knots in following seas. But a concern now is overcharging batteries. We did play with motor sailing and putting low amp draw while the sails are up to give us just a little push. On a clear day it seems that we can approach a relative neutral draw on the batteries from the solar input and sails up. I'm not sure how much push we are actually getting but it could negate any prop drag.
Cheers
Patrick
____________
From: aweekdaysailor <aweekdaysailor@
To: electricboats@
Sent: Monday, August 10, 2009 7:29:27 PM
Subject: [Electric Boats] Re: New Member and New Electric Boat Conversion
Thanks Patrick - very nice report on a well-done rig. (I need to find those nice insulators on your motor)
I am also encouraged by your regen numbers - is that a 2-blade or 3-blade prop? Also what type? That's getting into the range of practical - for example 200watts is probably near your house load.
But I would caution you on estimating your total usable capacity. For those batteries, I get a calculated Peukert exponent of 1.17 - among the lowest available in lead-acid which is great. But I show only 66AH available at a 75AH rate (to 80%) even with your 126AH rating on those batteries (Peukert still strikes) - so basically 45-50 minutes of total runtime (ignoring solar and regen). Doubling the batteries would give you ~2 hours of runtime - about 130% gain on 100% investment.
My main concern would be that you inadvertantly run those nice batteries below 80% and greatly shorten their life.
http://sites.
http://www.odysseyb
Nice job and hope this helps!
-Keith
--- In electricboats@
>
> Good Evening,
>
> It is exciting to see the possibilities of electric boats and I can now say that I now have experienced the possibilities of what electric boats have to offer.
>
> Here is my basic profile.
>
> Boat: Serendipity 43' 1981 IOR race boat.
> Displacement: 17,000
> Draft: 8'
> Beam: 13'
> Old Power: Pathfinder 50HP diesel
>
> The goal of my re-power was to integrate the powerful rig for regeneration
>
> Here is some of the data we received from our recent trip from Santa Barbara to Channel Islands Harbor (~30nmi).
>
> Propulsion Marine 4.7 KW inboard electric drive
>
> Mars 4.7 KW brushless permanent magnet AC motor
>
> Sevcon Millipak controller
>
> Browning 3301 gearbox with 4.87:1 gear ratio
>
> Propeller 17 x 17 Left hand which required you to change the fan on the motor
>
> dripless stuffing box by PYI
>
> 4 Odyssey 2250 batteries with 6.3 KWH total energy, 5 Kilowatt hours of usable energy.
>
> 3/0 x 10 feet cable run from batteries to controller
>
> propeller turns at 470 rpm, motor turns at 2288 rpm, draws 85 amps on a bollard pull, 70 amps at 3.7 knots
>
> solar powered using two Sanyo 200 watt panels and Outback Flexmax 60 charge controller. Have witnessed 400 watts charging current. Capable of Solar motoring which adds about 1 knot to speed by negating propeller drag and adding a small amount of thrust.
>
> Regenerates at 200 watts at 6 knots in light breezes, more is expected in heavy breezes because boat has previously logged 10 knots boat speed in 25 knots of wind.
>
> On our test sail from Santa Barbara to Oxnard in light breezes we witnessed 570 watts of total generation consisting of 370 watts of solar power plus 200 watts of regeneration.
>
> Batteries were refilled in 2 hours after discharge from harbor maneuvering
>
> The system was professionally
>
> www.abovethewaterli
>
>
> http://www.propulsi
>
> Cheers,
>
> Patrick
>
>
>
>
> [Non-text portions of this message have been removed]
>
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