Question:  What are the best procedures for installing and maintaining Battery Backup Systems? 

 

:Answer:   Republic ITS recommends installing BBS only at critical or important locations, and at least annual testing and replacement of batteries on a 3-5 year schedule.  A quick review of ITE and IMSA websites did not show any relevant publications.  Surveying a few SF Bay Area agencies revealed the following:

  •  Battery life seems to be about 5 years.  Costs to repair batteries is about $1,300 every 4 years.  These costs are high enough that they should be considered as part of the decision to install BBS or not.  (Thanks to Mike Vroman, Mountain View)

  • Installing BBS makes the most sense at arterial-arterial intersection only, and at other intersection that are so close by they might cause queuing problems if not also equipped with BBS.  (Thanks to David Huynh, Fremont)
  • BBS can be tested as part of quarterly or annual signal maintenance.  Shut off the main power when starting the signal maintenance.  Let the signal run on BBS for the duration of the other maintenance activity.  Annually conduct a load test of each battery.  Test results can determine when the battery is near the end of its life. (Thanks to Dennis Ng, Santa Clara)