Parabolic Charge
Do not buy this battery. Charged it in one hour. Depleted it in one hour. Determined the formula for the charge percentage. Created a parabola.
y = a * (x - 60)^2 + 100
y = a * (x^2 - 120x + 3600) + 100
With point (0, 0):
0 = a * (0 - 0 + 3600) + 100
-100 = 3600a
a = -100/3600
a = -1/36
y = (-1/36)x^2 + (10/3)x - 100 + 100
y = (-1/36)x^2 + (10/3)x