To lead with the outcome, the vast majority of VRLAs in the network are OK. That is, they are generally within our expectations. I should also make it clear that historically, the vast majority are 2V cells, although that is now changing as more and more monoblocks are installed.
How do we know they are OK?
Two sources of data.
Historically, we have routine test discharge data from the field, and we have our scientific field trials and studies.
More recently we have routine Battery Condition Monitor functions in our rectifiers which helps identify bad banks, and we also have programs of random population sampling.
