Float voltage: EnerSys temperature compensation

Float voltage per cell against battery temperature: the EnerSys OPzV table (2.37 V at −10 °C … 2.25 V at 20 °C … 2.21 V at 40 °C) with the ±30 mV/cell alert band. Dot: measured string voltage ÷ 54 at the measured battery temperature (grey while the charger is off). Below: float current, measured vs. the twin's expectation.

EnerSys float table±30 mV/cellMeasured (trail)

Ohmic value per cell vs. baseline

Internal resistance of each of the 54 cells from the battery monitoring system, against the EnerSys 0.51 mΩ at 20 °C corrected to the battery temperature. Lines: +20 % investigate, +50 % act (typical field practice). Red bar: a cell more than 1.5× the string mean.

Cell ohmic valueBaseline+20 %+50 %

DC system

AC supply, thyristor charger with its filter, the 110 V DC bus and its loads, the 54-cell battery and the insulation monitor, with live sensor values. Red = beyond the twin's alarm limit.

Condition sensors

Bars against the alarm limits in the twin file (red line).

Twin health: expected vs. actual

Measured vs. expected