Actually, today 575 farads is no big deal for the new super caps. Someone
recently listed some used super caps rated 2600 farads at 2.7 volts for
only
$10 each. You could wire enough of these in series to get enough voltage
to
turn the starter but it would get kind of expensive, even at $10 each, to
wire enough in series/parallel to get enough capacitance and voltage. For
instance, 5 of them in series would give you 13.5 volts but cut the
capacitance to 520 farads, which might be close enough to the 575 farads
that was figured earlier, if it is accurate. I didn't check. Auto
batteries
typically measure 13.8 volts when fully charge, by the way.
If you wanted to try something like this, you would have to be extremely
careful to limit the voltage because the super caps are very sensitive to
overvoltage and will die. So, you would need to build a charging supply
for
the caps that was limited to an absolute maximum of 13.5 volts and it
would
most likely be much better to leave some room for error and limit it to
less
than this.
Paul
Think Positive
On Mon, Oct 10, 2011 at 1:34 PM, mike hollingsworth
<megavolts_61@xxxxxxxxx>wrote:
To put a little more into what Brandon said, one must think about what
is
required to crank a starter motor. A typical car battery can provide,
for
example 840 cold cranking amps @ approx. 14.6V. This means for a short
duration, this would amount to more than 12.2kW of power. If it takes 5
seconds(just a number to work with), this would amount to a capacitor
that
would be able to store about 575 farads! It is possible that it doesn't
take but a second or two to get the car started, but you get the idea.
Those jump packs Brandon mentioned are great, but I have a battery
booster
pack and it is NOT a capacitor. It is a sealed lead acid battery.
Mike
________________________________
From: Brandon Garretson <garretsontech@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Thursday, October 6, 2011 6:36 AM
Subject: Re: [TCML] Help with capacitor + ignition coil project
I dont wish to discourage anyones creativity here and speaking from a
mechanics point of view;
Power to the coil is all well and good but from where would you obtain
the
several hundred amps required to engage the starter and turn the engine
over
several times in order to start it?
That would require one hell of a large cap, like say, a car battery.
Just the alternator turning fairly slowly creates enough juice to power
the
ignition, thats why cars (manual trans) can be push-started.
Just wanted to point that out now because odds are somebody would point
it
out later.
There is an existing device called a jump-pack that can generally create
~1000 amps.
Im fairly certain it operates in a similar fashion to what you are
proposing
but creates a more desireable outcome.
http://www.amazon.com/Quick-Cable-604050-WSL-RESCUE/dp/B002YORJTK/ref=dp_return_2/190-7458553-3559110?ie=UTF8&n=15684181&s=automotive
Maybe there is some way you can put a twist on the concept.
Or hell, buy one for 80 bucks, pull the guts out, build your own case and
call it yours.
Just remember to remove the Made In China sticker.
>
>
>
> >
> > Hey guys, I have an idea for a science fair I plan on entering this
> > spring.It will involve capacitors, and a few simple car parts.I
> > really
> > need help with this because my knowledge of capacitors sucks...so if
> > anyone would be able to help send me in the right direction I would
> really
> > appreciate it!email me at b-u-r-t-o-n-boy@xxxxxxxxxxx if your
> > interested!(basically my idea is when you have a half dead car
> > battery
> > that wont start the car, you can charge up a capacitor to send enough
> > power to the ignition coil.... kinda like a flash in a camera)
> > thanks! :)
> >
> _______________________________________________
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> > Tesla@xxxxxxxxxx
> > http://www.pupman.com/mailman/listinfo/tesla
> >
> >
>
>
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>
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