I wonder if they've thought of NiMH D cells. Seems to be a battery
type everyone overlooks, but they're very effective in hybrid cars,
and I use a 30 cell NiMH D cell car battery instead of lead-acid.
(Partly, disinformation from the oil companies has been very
effective at getting everybody to look anywhere else, because flooded
NiMH batteries (cheaper but suppressed by big oil) made the GM EV-1
and other great cars featured in "Who Killed the Electric Car?" what
they were.
(Nickel-iron is also far better than lead-acid for any applications
where they're actually being used - discharged and recharged. They
last for decades. Changhong[.com] makes them. Tenergy
[all-battery.com] makes good NiMH D cells.)
The simplest way to use NiMH D cells as 12V batteries is as I
describe as "Handy Battery Sticks": put 10 cells end to end into PVC
"1.25 inch irrigation system" pipes, 24-7/8" long. Cut end plugs from
3/8" ABS with a 1-5/8 inch hole saw. The inside diamter is just right
to fit in the pipes. Put a 1/4" s/s bolt through the hole made by the
hole saw, tighten a nut on it, and glue it into one end with the head
inside. Now you have a pipe with a threaded terminal sticking out one
end. Slip in the batteries and do the same at the other end, keeping
a bit of pressure on to ensure the cells make good contact with each
other and with the bolt heads inside. Use methylene chloride or
ABS/PVC slovent cement. (Try not to breathe the fumes.)
You now have a 10 amp-hour, 12 volt, maintenance free battery that
should last a decade or two - maybe even longer. It'll be just over 2
feet long. If that doesn't fit, 2 batteries of 5 cells for 6 volts is
1/2 the length (pipe 12-7/8"), or 5 batteries of 2 cells for 2.4
volts is 7" long (pipe 5-7/8) and 3 or 4 sets fits in a lead acid
battery box. You can also use regular ABS or PVC "1.25 inch" pipes -
they're just heavier, and the end plug size will be smaller. (1.25"
pipes that actually are 1.25" I.D. aren't quite big enough.)
I've got my 3D plastic printer, and I plan (among many other things)
to make 10 cell/12V NiMH D cells battery holders in a compact 2 long
x 5 cells pattern. But by the time the connections are installed in
the plastic , I doubt they'll be easier to assemble than the 2' pipes.
Now the differences in chemistry: NiMH is a great, lightweight, very
long life car battery since the 13.8 volts standard car charging
voltage is the ideal NiMH float charge voltage. When not in use and
fully charged, the voltage will sit somewhere around 13.5 volts.
However, most lead-acid battery chargers will try to bring the
voltage up to 14.4 volts (or even higher), which the NiMHs will
refuse to rise to except under extreme duress and much heat. They
might leak. 14.2 is the usual moderately fast charge cutoff. I prefer
to simply give them 13.8 volts, period, which can be left connected
indefinitely (like in the car). That does reach full charge more
slowly, but it's gentle and foolproof. You might have to put a diode
or two in series with a lead-acid charger to drop the voltage, and
then you might have to put a resistor across the diode so the charger
senses there's a battery there.
Cheers,
Craig
>Here's something interesting someone is doing with Torqueedos. This
>guy is going to push a 48' trimaran around the great loop with two
>of them. I spoke with him and "he says" that he can get the boat up
>to 10mph with them and cruise real time off 2.5 kW of solar power at
>6 mph. The boat is apparently very light for it's size and only
>draws 18". He's using agm batteries and had quite a negative opinion
>of Lithium Ion technology when we talked about his design. Not sure
>why.
>
>http://bwsailing.com/cc/2012/08/01/solar-odyssey-around-the-usas-great-loop/.
>
>http://electricsolarpoweredboat.com
>
>From: sirdarnell <sirdarnell@yahoo.com>
>To: electricboats@yahoogroups.com
>Sent: Saturday, August 18, 2012 10:23 AM
>Subject: [Electric Boats] Re: Electric Outboards?
>
>
>http://www.all4solar.com.au/
>
>--- In electricboats@yahoogroups.com, "luv2bsailin" <luv2bsailin@...> wrote:
> >
>> John,
>> I really don't think you'd be happy with any of the electric
>>outboards on the market. Sure you could motor along in mild
>>conditions, but for situations like backing into a 20MPH wind that
>>you mentioned I think you'd be underpowered. Keep in mind you have
>>a lot of windage from the hull and rig to overcome, besides the
>>water drag and inertia.
>> If you already have an inboard, why not just replace it with an
>>electric motor and use your existing shaft and prop?
>> Jim McMillan
>>
> > --- In electricboats@yahoogroups.com, oak <oak_box@> wrote:
> > >
>> > Yes, I've heard that too. Of course, it would be interesting
>>to hear the context - was it on an inland lake, or out in open
>>conditions with current and large waves?
>> > Â
>> > I can tell you my Atomic 4 gas engine with 30HP is wayyy more
>>than I need on the lake. I cruise at 5-6mph with the throttle
>>very low. And I have to take it out of gear in the marina to slow
>>down enough when I'm nearing my slip (and still hit reverse to
>>stop).
>> > Â
>> > John
>> >
>> >
>>
>
>
>
>
>------------------------------------
>
>Yahoo! Groups Links
>
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