SMA SI 3324 Installation - Manual (Page 101)

SMA Technologie AG Battery Management
Installation Guide SI3324/4248-14:SE2406 Page 101
11 Battery Management
The service life of batteries in off-grid applications can vary greatly. With proper
handling the batteries can last as long as 15 years. The main causes of premature
aging are incorrect charging and frequent deep discharge. For these reasons, the
Sunny Island 3324/4248 has an intelligent charge control and reliable deep
discharge protection. When these features are properly used, the battery service life
can be greatly extended in comparison with simpler devices.
When first commissioning the inverter, selection of the correct battery type ("23-2
BatType" parameter), the correct battery capacity ("23-3 AmpHoursBat" parameter),
and the maximum battery charging current ("23-4 AmpdcBatMax" parameter)
automatically sets all other adjustable battery parameters to sensible values. Further
optimization of the charge parameters should not be necessary. However, check the
battery manufacturer's recommendations for any special requirements.
All types of lead acid batteries are supported. The battery management system
draws a distinction between sealed lead acid batteries with liquid electrolyte (FLA,
Flooded Lead Acid) and the sealed lead acid batteries with semi-solid electrolyte
(VRLA, Valve Regulated Lead Acid). All Gel and Absorbed Glass Mat batteries
belong to the last group (AGM, Absorbent Glass MateSeparator).
The battery capacity is to be entered as the nominal capacity for a ten hour discharge
(C10). If this is not available from the battery manufacturer's data sheet, then
calculate this from the data for different discharge times (120 h, 100 h, 20 h, 5 h,
1 h) in the following manner:
C10 C120/1.28
C10 C100/1.25
C10 C20/1.09
C10 C10
C10 C5/0.88
C10 C1/0.61