Ben,
You're definately on the right track. You should see if you can put at least some of the batteries where the fuel tanks used to be. That puts the weight right back wher it started. Many people split their packs, my 48V pack is built with 24V on either side of my cockpit, it's just a little more cable and if the cabling is sized right, virtually no performance drop.
Keep thinking, your conversion has gotten better already.
Fair winds,
Eric
--- In electricboats@yahoogroups.com, Ben Okopnik <ben@...> wrote:
>
> On Fri, Jun 24, 2011 at 04:41:44PM +1000, chris Baker wrote:
> > Hi Ben,
> >
> > I'm a fan of Thundersky batteries, having had them on my trimaran for a couple of years now, and I'm putting another set into a solar boat right now.
> >
> > A suitable set of Thundersky (or CALB) cells could be based around the 400ah cell. They 3.2 volts each and you'd need say 24 of them for your target 72 volts. So a much smaller battery farm than the trojans.
>
> That's a pretty amazing cell; surprising power density, especially for
> that low weight. The biggest problem is the cost: $430 apiece here, so
> over $10k just in batteries alone is prohibitive. But it sure would be
> nice. :)
>
> I just ran across the L-16 type Crown CR-395 battery; 395AH @ 6V, so 12
> of these would give me what I need. Just over $250 apiece, which works
> out to just over $3k total; 121 lbs. and a 12.2"x7.2" footprint, so
> under 1500 lbs. and two rows (roughly) 1' wide and 4' long. That should
> fit in my engine compartment - although it will shift the weight
> distribution quite a bit: currently, I have 2 x 50 gallon diesel tanks
> in the main salon, with their centers about 5' forward of the engine
> compartment; between the fuel and the tanks themselves, that's about
> 1000 lbs. The diesel itself sits right where the batteries are going to
> go. If I remove the tanks and the engine and install the batteries and
> the motor, the weight swap will be fairly close to even - but as I've
> mentioned, the distribution is definitely going to shift quite a bit.
> I should probably consult a marine architect, but I have a sneaking
> suspicion that it's not a viable setup. I might have to see what the 60V
> power curves look like, or look at AGM and the like.
>
> Thanks, Chris - that was really helpful!
>
>
> --
> Ben Okopnik
No comments:
Post a Comment