From: Eric <ewdysar@yahoo.com>
To: electricboats@yahoogroups.com
Sent: Wed, January 26, 2011 11:53:16 AM
Subject: [Electric Boats] Re: Electric speedboat revisited
AK,
I've been reading the posts concerning your planned conversion, and it looks like the most realistic proposal for the conversion of a speedboat that has been covered here. The key factor is your planned usage (use case). Recognizing that most of your time will be spent at low speeds in the canals will allow you to achieve reasonable use on a single charge.
A rule of thumb that I use to evaluate a battery bank capacity to gasoline usage is that 10k-11k Watt Hours (Wh) of battery last about as long as 1 gallon (4 liters) of gasoline through an ICE. Your proposed 60x100Ah bank has about 18,000 Wh total storage or about 14.4k Wh of usable (to 80% depth of discharge). So your proposed batteries should act alot like 5-5.5 liters of gasoline. You've probably noticed that a day of canal cruising doesn't use very much fuel, that is in your favor. However, your 130Hp ICE can probably burn more than 40 liters/hour at WOT. I figure that if your proposed setup can deliver the same performance (it should be close), then you would also be able to drain your batteries completely in less than 10 minutes at WOT.
So I think that your proposal is sound, as long as you accept the limitations. I had to go through the same process when I replaced a 2hp ICE outboard on my dinghy with a Torqeedo 801. The dingy performs about the same, but if I consistantly try going fast, the battery doesn't last very long. The better that I manage the battery, the more pleased I am with the overall performance of the electric solution.
Fair winds,
Eric
Marina del Rey. CA
--- In electricboats@yahoogroups.com, "ams_ak@..." <ams_ak@...> wrote:
>
> Roderick, Dave, thanks for the thumbs-up. I felt that the power and weight advances in parts now reasonably available would make this conversion feasible, glad to find I am not alone.
>
> -Rod
> The Canals in Amsterdam are fresh water and there would be no plans for going out on the Northsea any time soon, unless I go a little Wilde myself. Still the plan will be to keep the motor dry, much more so than the ICE in the original setup. I am leaning towards the Winston (Thundersky) LiFePo, in part because I could then source motor-controller-battery from one place within the EU (Kostov).
> Cool that you are expanding your interest to this side of the Atlantic. I saw your LR challenge a while back and remember thinking we could use some more of that over here!
>
> -Dave
> There is a forced air cooling fan available with the Kostov, making cooling more independent of RPM. Probably a good addition for this setup.
>
> So I wont be too heavy, and I should have enough power, but range will still be a question. I posted the weight calculation for 60 100Ah lithiums, in part because it shows that the new setup could be a little lighter than the original. Kostov recommends going with an 80 x 100 setup, extending range and high RPM (voltage) performance. It adds 70 kg / 150 lb but if budget allows... well thats always the if :)
> Either way the motor and controller will be capable of draining the pack real quick, so its a good thing you can also really get a kick out of quiet slow speed cruising. And maybe sneak up on some fish ;)
>
> AK
>
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