We can look at the same sort of summary for the monoblocks. Pre-94, 6V monoblocks in standby service achieved about 4-6+ years before significant., while 12V footprint gave a little less. To be clear though, there was not many applications in Telstra which used 12V monoblocks back then.
Noticeably, there were incidences of specific problem which skew this experience. Some of these proved to be inferior product (that is 5-year product masquerading as 10-year product, while others were cause by specific problem put down to maturing product. Suffice to say there very little pre-94 product left in the network.
For post-94 group, we still did not believe the long-life claims for monoblocks, (really this means that we didn’t have any real new evidence of improvement) and we expected about the same level of performance. To some surprise, the more recent product has improved, and in controlled environment we see, or expect to see up to 8 years out of some types of VRLA (AGM) monoblocks. One type we thing will last in excess of 8 years in both the 6V and 12V foot print.
The overall message here is that there has been an improvement in monoblocks, yet generally we don’t expect them to give the survive life we see for 2V single cells
