The lower pH is, the sourer the taste is.
lime – citric and ascorbic acid, pH around 1.8
lemon – citric acid, pH around 2.3
vinegar - pH 2-3
rhubarb - pH around 3.3
avoid charging above 80% and discharging below 20% to maximize battery lifespan. While they can be charged to 100% and discharged to 0%, doi...