DaleSpam said:
A battery is based on a electro chemical reaction which has a specific voltage, so you cannot vary the voltage.
You can choose the voltage by choosing which battery.
DaleSpam said:
If you take a voltage times a current, what kind of unit do you have?
Power.
What if you connect the positive and negative ends of two batteries by direct contact. What kind of magnetic field does that produce versus having the given current remain as long as possible within a wounded coil of some unspecified length? Is the integral of the magnetic field along infinitesimal lengths of the wire proportional only to the current? No it is not. If you want the charges to go farther, and maintain the same current, you have to choose a different battery, one that has a higher voltage. Doing so generates a greater magnetic field.
d\mathbf{B} = \frac{\mu_0}{4\pi} \frac{I d\mathbf{l} \times \mathbf{\hat r}}{r^2}
(in SI units), where
I is the current,
d\mathbf{l} is a vector, whose magnitude is the length of the infinitesimal|differential element of the wire, and whose direction is the direction of conventional current,
d\mathbf{B} is the differential contribution to the magnetic field resulting from this differential element of wire,
\mu_0 is the magnetic constant,
\mathbf{\hat r} is the unit displacement vector from the wire element to the point at which the field is being computed, and
r is the distance from the wire element to the point at which the field is being computed.
As you can see, the magnetic field contribution is determined by the product of the current AND the distance traveled by that current. If we choose the voltage by choosing the battery, we can maximize the power for the same amount of current, because we can make that current travel farther. Therefore, my point here is to show that the amount of magnetic field we can get from a battery's charges is limited by its voltage. There is no fundamental and natural limit that I am aware of that prevents high voltages from getting more magnetic field out of a given charge.
Take for example the product of volts and amps. Assuming that we have the same amount of charges (for whatever battery we choose here) and we're trying to produce the same amount power, we could choose a battery that will last twice as long by choosing a battery with twice the voltage and the same capacity and reduce the current in half (because half the current means half the drain). Reducing the current could be done by increasing the length of the coil wire by four times. But doing this also increases the magnetic field because while the current is only halved, the length of travel is quadrupled! How you can you increase the magnetic field yet have the same power? Since this is basically an electromagnet, one can switch the current to get a magnet rotating. Yet with a bigger magnetic field, we can take advantage of this and use a bigger magnet, for the same power! Does this make sense?
I believe its reasonable to assume that the magnetic field is produced by current momentum, the product of current and distance, not just current. Now my question is, in what ways is the total magnetic field that can be produced limited by current alone?
