Is there a formula or can it it be explained to a layman? I really appreciate any help with this. Even if it's something I couldn't build, it would be nice to understand how it works. I understand volts and amps, how does resistance come into play with it all?
Current (in Amps), voltage (in Volts), and resistance (in Ohms) are linked by "Ohm's Law". Such that voltage divided by current yields Ohms. Likewise, by algebra, Voltage divided by resistance equals current or current times resistance equals voltage. Knowing any two allows you to calculate the third.
https://en.wikipedia.org/wiki/Ohm's_law
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ohmlaw.html
https://www.electronics-tutorials.ws/dccircuits/dcp_2.html
Like knowing the MPH of your car and how far can tell you how long it takes to get there. Or, knowing how long in time and miles gives you your average speed. Distance, rate and time like voltage, current and resistance.
In the case of LB the actual voltage (considering all the drops) is about 15 Amps at .75 Volts, so the screen part of the box is about (.75 divided by 15), .05 Ohms (1/20 of an Ohm), very close to a short circuit. One of the big issues is there's nearly as much other losses (due to resistance) internally to the 'battery' and connections. And the actual resistance of the SS screen changes with temperature some (goes up a bit).
In most cases resistance determines the current for a given voltage. This is why the same 100 Watt light bulb works on the same outlet a 1500 Watt toaster does. The bulb just has a higher resistance (and therefore lower current). Here, voltage (in Volts) times current (in Amps) gives power in Watts.
Ready for the test?
You can probably do OK with a
current limited supply at about 15 Amps with a limit if say 2 Volts? Not an easy task, really. Add to that that you should use fairly thick wires (say 14 AWG) from the supply to the box for such currents and it rapidly becomes a tough job mechanically.
I got some fair results with attaching a
D cell with short leads. It tends to hammer them hard, but you can get close to an hour heating under ideal conditions, most of it usefully hot. Using NiCd rechargeables gave shorter run times but rechargeable. The NiMH I tried didn't work due to internal resistance (there's resistance inside), so I used a NiCd from a rechargeable tool I had handy.
All in all I thing MF has done a very credible job. I abandoned my attempts and went with theirs.
Regards to all.
OF
Edit: To expand a bit on this, the Navy used to use 'the water example'. Here pressure (voltage in the electrical world) is measured in PSI typically. Flow rate (current) is in 'Gallons per minute' and resistance (small pipes and other constrictions) determines how many GPM you get for a given PSI. Raise the pressure, or lower the resistance (bigger/shorter pipes) and the flow rate goes up?
Perhaps that help? Prolly not.
OF