Dan Baker wrote:
> Yes these would be excellent PM controllers, however they cost as much
> or more than the motors (paid $100 each + tax for them at local
store).
One source of cheap (in all senses of the word) controllers are junked
electric scooters. They generally have two 12v batteries in series, and
so are 24v input. They drive a single 24v motor, but in your case, you
can connect the two 12v motors in series and the controller won't know
the difference.
You'll want to measure the actual current that the motors draw, and pick
a controller that can deliver at least this much (preferably 2 or 3
times more if you're using Chinese controllers). A "250 watt" controller
means 250w/24v = 10.4 amps max. If you really have 410 watt motors, they
would draw 410w/12v = 34.2 amps, but I suspect that is marketing
baloney.
> Of course the next step might be to go with a single motor retrofitted
> to an old outboard bottom end
A friend of mine has done just that. I think it's an old 24v floor
scrubber motor, rated at roughly 2 HP, mated to a dead outboard motor's
lower end. It worked out extremely well.
> Once I ever get the solar panel built, it will put out 280 watts in
> full sunshine. Since a leisure boat spends 99% of it's life parked the
> panel should keep the batteries charged for weekend excursions.
That's a reasonable strategy. But again, I'd be surprised if the PV
panels ever deliver their rated power.
> I think I have found a way to build them but I need to find some
>tempered glass. I've seen others just glue the cells face down (by
>their backs only) to the glass with a corrosion free watertight
>silicone.
This works, but you need the right sealant. I used Dow Corning 1-2577
conformal coating, which is rated for this application. Lay the cells
face down on the glass, wire them up, and test them. Make a dam around
the edges of the glass with tape, level it, then pour about 1/8" of
1-2577 on it. Look on the bottom, and slide and move the cells as needed
to work out any air bubbles between the cells and glass. When it cures,
you'll have a waterproof assembly that won't degrade or yellow with age
and from UV light.
> I've thought of putting something on the front barrels to smooth the
> flow however I haven't found anything yet that is strong enough to
> take the odd run a ground or hitting a rock.
My cousin built a boat rather like yours, except he made the pontoons
out of plywood for each side. They were square of course.
Just a
ramp in the front. But then he filled them with that self-expanding foam
insulation. Beware; it expands quite forcefully; his first attempt
pushed the sides off the plywood pontoons!
So, I imagine you could slice the end from your front barrels, force it
flat with some bolts, and then blow it full of this foam. This would
give you a point on the front, yet it would still be "unsinkable".
> Would I be able to reduce/increase power to the motors to steer?
Generally yes. Electric motors are pretty tough, and can easily run at
2x rated voltage and current for a short time. The propellers might
cavitate though if you run them too fast.
--
Lee A. Hart | Ring the bells that still can ring
814 8th Ave N | Forget the perfect offering
Sartell MN 56377 | There is a crack in everything
leeahart earthlink.net | That's how the light gets in -- Leonard Cohen
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