Energy storage
 

Hello all, I am working on a project I had had in mind for some time
now, I am looking for input on a certain aspect of it, to be more
specific, what would be the best way to collect electricity from 12 dc
generator [inductive] at varying voltage, condense it, and release it
at a moderated 12vdc at around 300-500 amps? I was thinking maybe a
big'ol capacitor and voltage regulator circuit, though I honestly don't
know alot about the different types of capacitors and their
capabilities. If anyone knows a good way to do this I would appreciate
it, or anywhere I could go to find out would be helpful to.

How much energy do you wish to store, for how long, and how long do you
wish to deliver the 300-500 amp output? It is possible to get high
current out of fairly small capacitors, but only for a short time.
Batteries generally work better for high energy storage. You might
want to search for info on hybrid automobile energy storage systems.

Some simple formulas for (ideal) capacitors:

energy = (voltage^2)*capacitance/2
current = capacitance*dV/dt
where dV/dt is the rate of change of voltage with respect to time

So a 1uF capacitor designed for extremely low inductance and low series
resistance, charged to 12V, could perhaps deliver 500 amps, but the
dV/dt would be half a volt per nanosecond...at a constant 500 amps, it
would be completely discharged in 24 nanoseconds. (The required
inductance would be less than half a nanohenry, which may not be
practical...) Note that capacitors aren't very good at delivering
energy at a constant voltage. "Supercapacitors" (available up to many
farads) could be a better option, but may be too pricey for you.

Rechargable batteries are commonly rated for ampere-hours of storage,
at a (reasonably) constant voltage, and for maximum charging and
discharging currents. A standard 12V automotive battery should be able
to deliver a few hundred amps, but maybe not at a full 12V terminal
voltage because of internal resistance.

Cheers,
Tom

Muhzark wrote:
Hello all, I am working on a project I had had in mind for some time
now, I am looking for input on a certain aspect of it, to be more
specific, what would be the best way to collect electricity from 12
dc
generator [inductive] at varying voltage, condense it, and release it
at a moderated 12vdc at around 300-500 amps? I was thinking maybe a
big'ol capacitor and voltage regulator circuit, though I honestly
don't
know alot about the different types of capacitors and their
capabilities. If anyone knows a good way to do this I would
appreciate
it, or anywhere I could go to find out would be helpful to.

Muhzark wrote:
Hello all, I am working on a project I had had in mind for some time
now, I am looking for input on a certain aspect of it, to be more
specific, what would be the best way to collect electricity from 12 dc
generator [inductive] at varying voltage, condense it, and release it
at a moderated 12vdc at around 300-500 amps? I was thinking maybe a
big'ol capacitor and voltage regulator circuit, though I honestly don't
know alot about the different types of capacitors and their
capabilities. If anyone knows a good way to do this I would appreciate
it, or anywhere I could go to find out would be helpful to.

I think it is revealing that Capacitor Storage is typically rated in
Watt/Seconds and battery Capacity is typically rated in Watt/hours ie a
typical Automotive storage Battery would be rated 100 amps at a 10 hour
discharge rate or about 1.2 Kilowatts hour

A hefty Electronic Photo-flash Unit would be rated at 50~100 Watt-Seconds

Yukio YANO