Saft evolion Technical Manual

Also see for evolion: Installation and operation instruction sheet Installation and operating instructions

Saft evolion Technical Manual Manual pdf 14 page image

15The Evolion is designed to provide low power to the application for autonomies ranging from 2 hours and 5 days. When providing thisduty, the voltage of the Evolion operates with the typical voltage range of a 48 V nominal telecom bus.5.1 Normal operating voltage limitsThe Evolion operates in a range of 42 Vdc to 56 Vdc measured on the module terminals.At 56 Vdc or an average cell voltage of 4.0 Vdc, the state of charge (SoC) is 100 %. In that state, the charge current accepted by theEvolion is approximately equal to the internal electronic load and the cells’ self-discharge rate, which is typically less than 0.1 A.At 42 Vdc or an average cell voltage of 3.0 Vdc, the SoC is 0 %. A low voltage disconnect (LVD) is automatically operated anytime amodule decreases to 42 Vdc (alarm #36). In that case, the Evolion module will remain active in safe mode until it automatically goesinto sleep mode to avoid over discharge.The operating voltage must be higher than 49 Vdc to keep the cell balancing circuits active during re-charge. The typical float voltagerange is 54.6 (86% SoC) to 56.0 Vdc (100% SoC). The maximum State of Charge (SoC) of the Evolion is directly proportional to thecharge set point voltage. For every 1 V less than 56.0 V, the Evolion will stabilize at approximately 10% less than 100% SOC.5.2 Cell self dischargeThe cell self-discharge rate depends on the temperature.Temperature (°C/°F) % per week20/68 0.6040/104 0.85 0.855.3 Open Circuit Voltage (OCV) as a function of State of Charge (SoC)The measured OCV is directly proportional to the %SoC. A linear approximation can be used. See the table and diagram below.OCV intercept (Fractional %SOC = 0) 46.62 VOCV Slope (0 to 1 where 1 = 100 %) 9.38 V per %SOC5. Cell and module voltages%SOCOC V (open circuit voltage)0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00565554535251504948474645444342OCV (Linear) = 9.38 x (fractional %SOC) + 46.62OCV of the Evolion moduleLinear (Approximation)