It's getting a bit time intensive to watch Mato drain her capacitors--and that's a good thing. Here's some results from a test this morning.
Starting at 6.8 volts (remember, she can charge to 8.1 volts), it took 19 minutes of run time to reach 5.8 volts.
From 5.8 volts to 4.8 volts took 16 minutes.
From 4.8 volts to 3.8 volts took 12 minutes.
That's 47 minutes of run time not starting from a full charge and not finishing on empty.
The output voltage from the boost converter is 12 volts, thus the amp drain on the low side increases as the capacitor voltage decreases.