It was also important to ensure the charging rate appropriate for the existing battery bank. At one hospital, the system was originally installed with three paralleled strings of eight 6-volt batteries. In the interim, as individual batteries failed, they had reduced the battery system to two strings, and then one string in an attempt to delay the inevitable replacement of the batteries. However, when the number of batteries was reduced, the charger’s maximum output setpoints were not adjusted. Battery electrolyte temperatures measured 50°C (the highest reading that the glass thermometer could indicate). Once the AC charging amps set point was reduced from 18 A to 6 A AC per inverter the battery’s electrolyte temperature dropped to 35°C—still hot, but not as dangerous or as damaging