I agree with Eric. Think of the battery bank like a bucket with a drain that is connected to the motor. You fill the bucket with energy from a generator, wind and/or solar panels. How fast you drain the bucket depends on the speed you run the motor. Also the bigger the battery bank (bucket) the more you can travel before you need to refill it. You can certainly do short trips with the energy stored in the bucket but eventually you will need to refill the bucket. If you just have a generator hooked to the motor you will always be depending on that generator working with no battery. back up to get you out of trouble.
Capt. Mike
Sent from on board BIANKA
http://biankablog. blogspot. com
From: "Eric" <ewdysar@yahoo. com>
Sender: electricboats@ yahoogroups. com
Date: Sun, 08 Aug 2010 15:30:48 +0000
To: <electricboats@ yahoogroups. com>
ReplyTo: electricboats@ yahoogroups. com
Subject: Re: [Electric Boats] Dreaming of Electric
One of the conversion factors used around here for sizing electric drives is 1kW of electric power for each ton of boat displacement. Given the size of your boat, you're looking at a system that can run at 14kW or around 19hp. This sizing is to provide basic safety manuevering in the times that you need it, not blazing performance.
Think about the size of the engine that comes in these boats. The Formosa 41s that I have seen have engines ranging from 50 to 75hp. Using the other conversion factor of 2 to 3hp ICE to 1 hp of electric, you can see that the 19hp suggested above is right on the mark, maybe even a little low.
Assuming that you have an electric drive system and generator are matched in voltage and electricity type (ac or dc) Your're going to need 14kW of generator. I'me assuming that you're thinking about this conversion becasue you already have this generator. Youre going to need at least one more just like it, or replace it with a properly sized one. Realistically, once you add in losses for a controller and voltage conversion, you're going to need something with more than 16kW of capacity to power your 14kW drive.
At the point that one chooses to power directly from generated power with no batteries, I don't see any significant advantage of a complex diesel/electric drive over a proven marine diesel installation. Going with a marine diesel will probably end up costing less overall. Check out the prices on electric drives around 14kW. And you'll have some additional issues synchronizing the generator to the demand that regular battery driven systems don't have to address. Personally, I would have a small battery bank to act as a buffer between the generator and drive system because I think that this would simplfy your installation and operation greatly, but that's just me.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@ yahoogroups. com, Pitt Bolinate <boombolinate@ ...> wrote:
>
> Hi again
>
> I think some of you misunderstand me, I do not want a bank of batteries to drive the boat.
> I would like to drive the boat with the gen set when needed and totally avoid the batteries,
>
> Sent from my iPad
>
> Bolinate! Pitt
>
>
>
>
> On Aug 7, 2010, at 6:40 PM, "Pitt" <boombolinate@ ...> wrote:
>
> I am so completely overwhelmed with the talk on this site, I mean this in a good way. I am a watching member of a few different forums and I am trying to live the dream. I am the proud owner of a Formosa 41 Ketch (see photo kharmaseas ). I have spent a year pulling everything oily and diesel stinky out, and dreaming about using the space for nicer things. The lazzaret is big enough for a well mounted generator and therefore keeping the main cabin machinery free.
>
> The whole package is 28 000 Lbs and the batteries are going to take all of the new found space. Honestly I would rather not bother with batteries and have a diesel/electric propulsion and really only sail with an emergency propulsion. I am starting to see the talk about honda generators being dodgy wired direct to the drive motor, am I correct this can be done?
>
> I have a diesel / air cooled generator. PowR-Quip PQDE 6500 ( see photo diesel generator ) Would I be dreaming to hope that a air blower would be capable of cooling the generator down in the lazzeret and using this generator to run the electric drive motor direct. Then keeping the old house bank as it is, charging with solar and from the generator when needed I keep being turned off the project with almost everybody telling me the boat is too big and it would take too many batteries. A new marine generator is too far out of budget and I already have this one.
> Some advice on electric motors would be welcome also,
>
No comments:
Post a Comment