The original tests were set to 2.4KHz, 3.7%. The mosfet series gate resistance (100 ohms multi turn, or can be a combination of smaller value multi-turns for more circuit stability in series to make 100 ohms) has to be adjusted until a chaotic waveform shows up on the 0.25 ohm shunt resistor. This chaotic ringing can easily be achieved but there is one sweet spot where the circuit will not consume battery power but rather charge the battery slowly.
Use a 2 channel oscilloscope and line the spikes up (as per the scope screen shot shown). <100ns_a_10-16-09.jpg>

Measure one channel across the shunt resistor and the other channel across the battery. You may have to use a x10 or x100 voltage divider when measuring the battery to avoid spiking / damage to the oscilloscope. Here is a screen shot of an oscilloscope showing what sort of voltages and transients you may expect: <TEK00004.png>

You may need to adjust the frequency and duty cycle to find the sweet spot on the chaotic ringing waveform. Adjust the series gate resistance first.
Other notes:For those researching and developing: If you change the resistor / inductance value, be sure to change the frequency / duty cycle appropriately to the inductive reactance and the resistance value.
Do not put a diode / capacitor across the load resistor to collect the back spikes. The mosfet / resistor will also get hot so ensure adequate heatsinking.
Ps..here is MIT and other universities caught in the HACK sorry ACT.

They should pay attention they may learn some thing

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