I've been playing around with a circuit emulator, and hit upon the idea of a PNP and NPN transistor pair back-to-back as a 'voltage pump', driven by an op-amp which is self-powered from that pumped voltage. It'll light a 100 watt 12 volt light and charge the battery at ~0.75 amps.
I'm unsure if this will work in real life, but here's the circuit.
And here's the text file for it:
Code: [Select]
You can go to http://www.falstad.com/circuit/circuitjs.html, click File > Import From Text, and paste the above text in to reconstruct the circuit.
If you slow it way down (so the time interval is 1 ps), you'll notice it starts out oscillating very slowly, and takes ~0.14 ms before it gets to the point that it can oscillate enough to pump the voltage. After that, it ramps up its oscillation rate until it levels off at ~7 KHz.
I'm unsure if this will work in real life, but here's the circuit.
And here's the text file for it:
$ 1 1.0000000000000001e-7 7.943983955226134 31 5 50
a -96 240 -16 240 0 15 -15 1000000 0 0
c -160 288 -160 256 0 0.0000010000000000000002 0.001
c -160 224 -160 192 0 0.0000010000000000000002 0.001
l -160 256 -160 224 0 0.001 0
t 0 240 0 208 1 1 0 0 100
w -16 240 -16 208 0
s 16 208 80 208 0 0 false
c 80 208 80 240 0 0.025 0.001
s 80 208 144 208 0 0 false
181 144 208 144 240 0 300 100 12 0.1 0.4
w 80 240 144 240 0
g 80 272 80 288 0
w -96 224 -160 224 0
w -96 256 -160 256 0
w -160 288 -176 288 0
w -176 288 -176 192 0
w -176 192 -160 192 0
d -96 288 -96 256 1 0.805904783
w -16 240 0 240 0
d 80 240 80 272 1 0.805904783
t -32 176 -32 208 1 -1 0 0 100
w -16 208 -16 176 0
w -16 176 -32 176 0
w -64 208 -48 208 0
r -64 208 -64 160 0 10
g -64 160 -48 160 0
w -16 240 -16 288 0
w -96 288 -16 288 0
w 144 208 144 176 0
s 144 176 208 176 0 0 false
v 208 272 208 176 0 0 40 12 0 0 0.5
174 144 272 208 272 0 100 0.9950000000000001 Charge Rate
w 176 256 144 240 0
w -96 224 -96 176 0
r -96 176 -144 176 0 1000
g -144 176 -160 176 0
w -160 192 -144 192 0
w -144 192 -144 176 0
w 144 272 144 240 0
w 144 272 144 288 0
w 208 272 208 288 0
d 144 288 208 288 1 0.805904783
o 7 64 0 12554 0.0001 0.0001 0 2 7 3
o 12 64 0 12554 0.0001 0.0001 1 2 13 0
o 23 64 0 12553 0.0001 0.0001 2 2 23 3
You can go to http://www.falstad.com/circuit/circuitjs.html, click File > Import From Text, and paste the above text in to reconstruct the circuit.
If you slow it way down (so the time interval is 1 ps), you'll notice it starts out oscillating very slowly, and takes ~0.14 ms before it gets to the point that it can oscillate enough to pump the voltage. After that, it ramps up its oscillation rate until it levels off at ~7 KHz.