I still think the system is best served by optimizing for thrust not regen since in no way is sail-derived electricity going to contribute significant energy back to the storage bank. To those who then say "but on long passages it will make a difference" I respond that on a long passage, the efficiency gained by optimizing for regen is inconsequential. Using some numbers that I seem to recall being bandied about this forum, you are looking at a ~20% improvement on a 40:1 (regen hours to motoring hours) ratio. So if we assume a 1-hour motor down a channel to open water, you are still looking at 32-40 hours of sailing (at 5kts plus) to recoup that hour.
The best way to look at regen is as like a deposit on beer cans, not as part of your base salary that you use for budgeting. If you do that, you will only ever be disappointed.
That said, what's good for electric propulsion is also good for regen: low rpms, large diameter props and aggressive pitch. I am sure that anyone fitting a new prop ideally suited to their new e-propulsion package will see better regen numbers than they would with their old prop that was matched to their ICE. The efficiency gained in propulsion will probably take out fewer electrons than the benefit to regen will put back, but the system gains either way.
I'll stop now since iPhone typing is a PITA, and I think I made my point.
/Jason
I can believe the facts as given because I have a theory to support them.I have been told that one cannot maximize a propeller for both thrust and regeneration at the same time and that both the pitch and the diameter would be different for a prop meant only to provide regeneration.The props that you guys are using are precisely the opposite in that they are props optimized only for thrust. Is it possible that the (un-optimized for regen) props must be "overcome" before any regeneration can occur? That the reason you must put it in gear and give it a slight bit of what amounts to forward thrust energy is that you are overcoming the resistance of a prop that is not set up for regeneration at all. Once you have the prop nearly providing thrust or at a thrust neutral speed it then takes only a slight additional push from the wind to get the boat into regen territory?Not certain what sort of prop would best be for a regen boat but perhaps it is a prop half way between a thrust optimized and generation optimized model if one would like to shoot for maximum efficiency over all? Maybe???.... digression, digression, digression... probably need a variable pitch prop...
From: acsarfkram <acsarfkram@yahoo.com>
To: electricboats@yahoogroups.com
Sent: Thursday, September 29, 2011 1:55 PM
Subject: [Electric Boats] Re: REGEN SUCCESS!Hi Mike,
Thanks for changing the video setting. You wrote; Did the happy dance in cockpit! I think I can hear the happy dance in your voice ;-).
When I first got my SolidNav Explorer the directions for regen (as I recall) where to put the forward/reverse switch in reverse and leave the throttle in the off position or maybe slightly on.
After the unit was installed I got an update on regen procedure and it was to set shifter to forward and apply a small amount of throttle.
In practice feathering the throttle to match prop freewheeling rpm (boat sailing speed) makes a sizable difference.
I have gone out for a two hour sail and returned with .02 volts more than I left with. Pretty minimal motoring, maybe ten minutes but still not too shabby.
Mark
Santa Cruz
--- In electricboats@yahoogroups.com, Mike <biankablog@...> wrote:
>
> I finally was able to observe my ASMO MARINE Thoosa 9000 system in regen mode after trying over three years. Strange thing was I was not even trying when I found it working. It was probably available all the time. I had recently started electro sailing instead of just letting the prop spin with the EP system off while under sail. One day when the boat was sailing along at 6 knots I checked the amp meter and noticed it had a positive amp flow. Did the happy dance in cockpit! You can see the regen in action here on my blog:
> http://biankablog.blogspot.com/2011/09/another-advantage-of-electric.html
> BTW I'm using the same three bladed prop I used with the diesel . Until I can rig up another meter so I can observe the regen more easily in the cockpit I'll continue to check on it from time to time Though it's not easy to keep a constant eye on it with current meter location. I'm still happy to know that it is working.
>
> Capt. Mike
> http://biankablog.blogspot.com
>
>
>
__._,_.___
MARKETPLACE
.
__,_._,___
No comments:
Post a Comment