SMA SI 3324 Installation - Manual (Page 108)

Battery Management SMA Technologie AG
Page 108 SI3324/4248-14:SE2406 Installation Guide
4. You can now determine the state of your batteries from the intersection of the
two lines in the coordinate system.
Here are four examples:
The Sunny Island 3324/4248 constantly compares the currently measured current/
voltage values with the characteristic curves. In order to reach a change in the
battery state, the values must remain below the characteristic curve for a certain
period of time. If only a very small discharge current is flowing (< 0.5 A/100 Ah),
then the jump to the next battery state is delayed for 30 minutes. At a discharge
current of 0.5 A/100 Ah to 2 A/100 Ah the time delay is only six minutes and at a
discharge current of > 2 A/100 Ah the measured current-voltage value must lie
below the characteristic curve for two minutes.
These delays are important to avoid faulty switching of charge states when switching
loads on and off. For the jumps back to a higher battery state, there is a voltage
hysteresis of 0.05 V/cell and an additional time hysteresis of 15 minutes.
Battery current relative to 100 Ah:
Your batteries have a capacity of 300 Ah.
The "12-2 BatCurrent" parameter shows a value of 30 A.
In order to determine the state of your batteries using the graphic chart (see
above) you must reference this battery current (30 A) with respect to 100 Ah.
The battery current shows a value of 10 A per 100 Ah.
1: You measure 1.95 V, the battery current is 14 A/100 Ah: Your batteries are
in Normal condition
2: You measure 1.93 V, the battery current is 11.5 A/100 Ah: Your batteries
are in a "Warning" condition; the generator is started and loads are
disconnected if discharge continues
3: You measure 1.92 V, the battery current is 10 A/100 Ah: Your batteries are
in a Low condition, loads are disconnected and if discharge continues then the
Sunny Island 3324/4248 enters standby mode
4: You measure 1.90 V, the battery current is 8 A/100 Ah: Your batteries are
in a Critical condition; the Sunny Island 3324/4248 switches to standby mode