BikeGen Stage 1: Is there an EE in the house?

I'm just gonna put it out there that I didn't do so hot in Physics at college.  I did get  B+ the second time around though...  In my flailing around, I ended up finding that placing resistors on my alternator output (rather than the field charging wire) would allow me to pedal with a low resistance level on the nearly dead battery.  I still haven't had a chance to charge it up full to try pedaling it at full charge.  In one attempt to find the proper level of resistance (Ω) to put on the line, I did burn up a rheostat, which was kind of cool in the setting-fire-to-electronics sort of way.  So what I've got right now is a set of three resistors, two 10Ω 10w and one 8Ω 20w all wired up in parallel on the alternator output line.  With this setup, I was able to ride for a full hour, keeping my heart rate at at about the 85% mark where I like it, and was able to increase the voltage measured at the battery during that time.  It went from 12.0v to 12.5v with no load other than the battery and the resistors, this of course started dropping as soon as I stopped pedaling because I really wasn't putting out that much juice so I was just affecting the surface charge.


Now back to those resistors.  I am a smart enough cookie to figure out that in parallel they make 3.0769Ω of resistance.  And I think they are capable of dissipating a combined total of 40w.  What I don't get at all is why in the hell that works to make the load easier.  I would have thought that increasing the resistance on the alternator output line would make it harder to pedal by causing a voltage drop that would be sensed by the alternator which would then try to work harder to make power.  But I guess this just demonstrates that there's something I definitely do not understand at work here.  I put the rheostat in the resistors' spot yesterday, that's when I burned it up, it could only handle 3w.  Burning electronic components smell really bad.  I think what I need is less resistance on the line.  With the rheostat I found by placing higher resistance on the line I could pedal easier, and with low resistance, there was a point where all of a sudden it was like hitting a brick wall.  So it seems a low ohm, resistor capable of dissipating something less than 40w is what I need, maybe.  I definitely don't know how to calculate what that is exactly.  I tried putting a small incandescent bulb inline to see what would happen, and the answer is absolutely nothing.  The bulb lights up and then the system never makes power.  So at the moment I'm stuck with my resistors.  Here's what it looks like now:

Just for kicks, I removed the resistors from the line, and replaced them with a 5a fuse, just to see if I was able to put more than 5a down that line.  The answer was definitely yes.  As soon as the alternator powered up, POP.  I replaced that with a 15a fuse which is more than I should be able to produce and it was, the 15a fuse remained intact.  If I had a 10a fuse I'd try that, cause if it worked, then I would be safe plugging my multimeter into the output wire to measure the current outflow.  Can't guarantee that yet though so I don't want to risk the meter.  Though I probably should wire some fuses into this thing...


So I'm kind of stuck, a little.  Another site I've come across says that that a 25Ω 25w rheostat on the field charging line will work, this I am skeptical of because the 25Ω 3w rheostat I tried didn't do anything at all, it was like it wasn't even there.  I'm more wondering what a smaller Ω rheostat with that higher wattage would do on the alt output line side.  Another diagram I found shows a fixed 0.47Ω 25w resistor on the alt output with a switch enabling a second one in parallel.  This is more along the lines of what I am wanting to try.  I would definitely appreciate some help in making sense of why the resistors seem to work where they do.