I just ran your test with my single cup Keurig brewer by Black and Decker. My batteries are 3 ea. group 24's and they were at 12.78 V. It took just under 3 minutes. The voltage sagged to 12.15 for the first two minutes, then it seems the heater must have turned off during the last minute because the voltage went up to 12.58. when done, after a few minutes the voltage returned to 12.7. I think I could brew several cups at this rate from my puny 24's.
However, at 5 am, I will not have 12.7X to start out with. It will be more like 12.5-12.2.
