Blood pressure is usually expressed in terms of the systolic pressure (maximum during one heart beat) pressure over diastolic pressure (minimum in between two heart beats) and is measured in millimeters of mercury (mmHg), above the surrounding atmospheric pressure (considered to be zero for convenience).
Corrosion on the terminals is due to hydrogen gas being released from the acid in the battery. It mixes with other things in the atmosphere under the hood and produces the corrosion you see on the terminals. Generally, if the corrosion is occurring on the negative terminal, your system is probably undercharging.
1 Low electrolyte level will cause a battery to die often. 2  Pull the battery terminals off and thoroughly clean them. 3  Car battery corrosion will impede the flow of electrons to the cables. 4  Charge the battery again and use a battery tester to make sure it holds the charge. Check and refill the electrolyte as required. 2  Low electrolyte level will cause a battery to die often. 3  Pull the battery terminals off and thoroughly clean them. 4  Car battery corrosion will impede the flow of electrons to the cables. 5  Charge the battery again and use a battery tester to make sure it holds the charge.