The laptop was charged from a fully discharged state while turned off. The voltage delivered to the laptop was only (11.46 -0.7)V because of losses across the current measuring resistor and the protection diode. The plot has a scale of 0.5V/square /0.8 ohms = 6.25 amps/square and 1200 seconds/square or 20 minutes per square. The full charge took 156 minutes at 7.75 amps.