I have run tests on a circuit simulator and it looks promising
http://www.falstad.com/circuit/index.htmlimport the circuit below and run it and you will see how it works
$ 15 5.0E-6 0.8729138363720133 37 5.0 42
w 432 464 376 464 0
t 360 416 360 464 0 1 -32.75407321681814 -1.001898182421428 70.0
d 328 464 328 416 1 1.1
w 328 416 360 416 0
T 392 336 328 336 0 0.01 1.0 0.05641978315192621 1.3411568216957717
w 328 368 328 344 0
w 328 344 344 328 0
w 344 328 432 328 0
w 392 368 392 392 0
w 392 392 312 392 0
r 360 416 408 416 0 270.0
w 408 336 408 416 0
w 392 336 408 336 0
w 328 464 312 464 0
w 312 464 312 392 0
w 344 464 328 464 0
d 432 328 432 264 1 1.1
r 432 328 432 464 0 1.0
c 344 496 376 496 0 1.0E-6 -31.752216753168796
c 312 304 256 304 0 1.0 15.500643839903205
v 256 248 312 248 0 0 40.0 5000.0 0.0 0.0 0.5
r 312 304 312 248 0 0.1
w 312 336 312 304 0
w 256 464 256 304 0
w 312 464 256 464 0
s 256 304 256 248 0 1 false
r 344 464 344 496 0 1.0
w 312 336 328 336 0
w 376 496 376 464 0
w 512 304 512 464 0
w 512 464 568 464 0
w 568 464 584 464 0
w 584 464 600 464 0
w 568 464 568 392 0
w 568 392 656 392 0
w 632 464 696 464 0
r 696 464 696 328 0 1.0
w 696 328 608 328 0
w 592 344 608 328 0
w 592 344 592 368 0
t 616 416 616 464 0 1 0.6672058599615411 0.7642448459782827 70.0
r 616 416 672 416 0 270.0
w 672 416 672 336 0
w 672 336 656 336 0
w 656 392 656 368 0
w 592 336 576 336 0
w 576 336 576 304 0
w 312 304 408 304 0
c 576 304 512 304 0 1.0 15.141472162905302
T 592 336 656 360 0 0.01 1.0 1.876725995304853 -0.04608639899762269
d 584 464 584 416 1 1.1
w 432 264 576 264 0
w 576 264 576 304 0
w 408 304 408 256 0
w 408 256 504 256 0
w 504 256 488 272 0
w 488 272 512 272 0
w 512 272 512 304 0
d 696 328 696 232 1 1.1
w 696 232 696 144 0
w 696 144 552 144 0
w 552 176 576 176 0
d 488 144 312 304 1 0.805904783
w 488 176 224 176 0
w 224 304 256 304 0
w 632 464 632 496 0
c 600 496 632 496 0 1.0E-6 -0.09698703844242118
r 600 464 600 496 0 1.0
w 584 416 616 416 0
r 576 176 576 264 0 1.0
w 224 176 224 304 0
T 488 144 552 176 0 0.1 1.0 1.1911478747794746E-14 0.05297292865979969
o 19 32 0 35 26.787715179656683 8.572068857490141 0 -1
o 19 32 1 35 107.15086071862673 9.765625000000003E-305 1 -1
o 18 32 0 42 37.41444191567111 2.993155353253689 2 -1
o 48 32 0 35 15.309010345804195 4.898883310657343 3 -1
o 48 32 1 35 74.82888383134222 9.765625E-55 4 -1
o 66 32 0 43 74.82888383134222 5.986310706507378 5 -1
you will notice additional resistors and capacitors on the circuit. these are only to make the applet work and not cause an error
The method to feed the output back to the source battery is to use the output of the second fan to power a 1 to 1 transformer and the output of this is then passed through a diode back to battery powering the first fan.
The primary battery will receive a pulse of normal electricity so slowing its discharge. In theory as the secondary battery will only receive ZP energy it should start to perform better and just maybe we will see an overunity effect in it.