The critical requirements for the battery are listed below:
*The battery to be used in the project must be maintenance free deep cycle tubular VRLA Gel Type Battery.
*Total backup time duration will be minimum twelve hours at 80% DOD
*The battery Voltage should be compatible with the solar module
The battery to be used must have passed the test according to IEC 61427-2005
Battery enclosure should be water proof, IP 65, with lockable arrangement.
*The warrantee period must be at least 2 years.