A battery pre-failure is not detected by Observium at the moment.
Currently the battery status shows as following:
But the iLO shows a pre-failure:
it seems that the pre-failure OID is not implemented in Observium.
The OID is .126.96.36.199.188.8.131.52.184.108.40.206.5.0.1 and value 15 (normal is 1) indicates a pre-failure.
The documentation about this check: https://support.hpe.com/hpesc/public/docDisplay?docId=emr_na-a00026525en_us