Wednesday, December 14, 2011

[Electric Boats] Re: Group Thoughts on 3.5kw system for 24', 5,000 lb sailboat

 

JB, regarding batteries: generally folks that go with the LiFePO4 battery bank, and a good BatteryManagementSystem, are happy. Lithium cells are sensitive to over- and under-voltages (fire or early death). When kept in their design limits, they seem to last forever. The BMS insures no cell:
1. gets too high during the charging process; otherwise one cell could "run away" with most of the charging energy.
2. gets too low at discharge; the BMS cuts off the whole bank.

Regarding 48v to 12v converter: the ones I got from ThunderSky actually give 13.6v, the good "maintenance" voltage for lead-acid 12v batteries. This allows a small 12v AGM or FLA battery to cushion the 12v load when lights, radio, depth, bilge want to play at the same time. The 48-12 converter keeps the small cushion battery charged.

Regarding prop: work with Electric Yacht. The motor RPM and shaft gearing should drive those decisions. James Lambden of Propulsion Marine has invested considerable time and money in optimizing prop to motor, and has found extraordinary distance efficiencies by getting it right.

Regarding wind generator: what are your off-dock electrical needs? A wind generator is standard cruising fare, but a huge inconvenience on a 24' sailboat.

Just my opinions,
Mark Stafford

--- In electricboats@yahoogroups.com, "JBWrites - San Diego Freelance Writer" <jbwrites2@...> wrote:
>
> Happy Holidays one and all!
>
> Have decided on a system for my 1963 Columbia 24 and would love to get the opinion of my fellow eBoat enthusiasts.
>
> First, the sailboat is a semi-full keel, which has been soda-blasted clean of 47 years of old paint and epoxy coated (not a single blister by the way!). It has an attached rudder with an apature for the prop. LOA is 24'4", 8' beam, and displaces 5,000 pounds.
>
> Powering the 3.5kw system from Electric Yachts of Southern Califormia will be a 48 volt, 120 amp-hour lithium battery bank; the 12 volt system will be powered off the mains via a 48v to 12v converter. In addition to the Regen capabilities (which I assume at 5% as the boat's theoretical maximum hull speed is something like 5.5 knots and too slow to really kick in) I am thinking about an Amp Air wind generator as there really isn't any space for solar panels. Of course, when tied to the grid there will be a 120 to 220 volt charging system in place.
>
> As for the prop, I am thinking of having a 3 blade, over-pitched 10:12 fabricated by Deep Blue Yarch Supply – otherwise, I'll be using the original 10:8, 3 blade that was parred with the original 8hp diesel that died with Disco back in the '70s.
>
> So, my open question to my fellow eSailors: Have I dotted the "I"s and crossed the "t"s?
>

__._,_.___
Recent Activity:
MARKETPLACE

Stay on top of your group activity without leaving the page you're on - Get the Yahoo! Toolbar now.

.

__,_._,___

No comments:

Post a Comment