Hi Mike,
Great post on your blog. We started around the same time with somewhat similar systems on our boats. Our sailing habits are different, you cruise and I mostly daysail with occasional 20-35 mile overnighters. Here are some of my thoughts on going electric.
I started out in May of '08 with my existing prop (fixed 2 blade 11x10) a SolidNav Explorer, one bank of four group 27 agm's and a Kipoint 48 volt charger. That got me running. The plan was to start there to get a base for performance numbers. To get those numbers (among other needs) I added a PakTrakr battery monitor. Now as things were added I would know what difference the changes made.
In that configuration I got a top speed of just about 5 knots and a speed of 3 knots with a 20 amp draw.
Next I added another bank of four group 31 amg's. This is a separate bank that is never run parallel with the other bank. My thinking with this arrangement is #1 - I have redundancy, if one bank fails I have another to fall back on #2 - extended range and #3 - one bank can be charged with a portable generator while motoring on the other bank, then switch banks when one is run down and the other is charged. This seemed like a simple way to setup an on-the-run charging scheme as it would be no different than plugging in at the slip. Truth be told I have never run my Honda 2000i on my boat but I'm guessing it would work.
Within the first year I changed the prop to a fixed three blade 12x10 and now get 5.7 top speed and 4 knots at a 20 amp current draw. I'm very pleased with this performance.
With the added bank the 48 volt charger had to be switched between the two banks, I could only charge one bank at a time. This worked fine until somewhat ironically the bank I added for redundancy had a battery go bad. In replacing the battery (warrantied) I realized the bank would not balance itself so I got a Pro Charging Systems quad charger (four separate 12 volt chargers in one case). This worked. Now I have two completely separate banks with their own charging. The upside of this arrangement is that both banks are left with the chargers on all the time the boat is at the slip.
Somewhere during this time I split the PakTrakr to be able to read both banks, pretty simple on-off-on switch but only one of the banks had current monitoring. I later added a second PakTrakr current monitor. With my seat-of-the-pants electronic abilities the switching for this was not so simple!
The latest addition is a shaft brake which enables me to stop the prop shaft from rotating while sailing (quiets things down). Also the Sevcon controller (early model) does not let the motor switch from forward to reverse until the prop stops. I had planned on getting the controller modified but this works so well I don't need to.
We don't really have A sailing season here in the Monterey Bay just different sailing seasons but going into my third winter season I too am very confident of the electric propulsion system in my boat, Lotus Flower.
Mark
Santa Cruz
--- In electricboats@yahoogroups.com, Mike <biankablog@...> wrote:
>
> Since it's the end of the year. I thought some here might be interested on some thoughts as I look back on the third season since I converted BIANKA my 30 foot sailboat to electric propulsion:
> http://biankablog.blogspot.com/2010/12/end-of-season-thoughts-of-electric.html
>
> I hope everyone has a Happy Electric New Year!
>
> Capt. Mike
>
>
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