In our story on extending UPS battery life, I wrote about how monitoring battery capacity is crucial. Well, Jim Reed, the president of battery monitoring company Power Data Systems in Boonton, N.J., wrote to add a few things to that list. Here’s what he wrote:
Hi Mark, we read your article “Four Ways to Extend Data Center UPS Battery Life”. While we agree with everything that you had suggested you neglected to mention anything about using permanent online battery monitoring systems with ohmic measurement capability that will provide accurate data into the health of the battery string right to the cell or jar level. This data will provide advance warning of batteries that are starting to exhibit a problem that will eventually lead to an early death. The IEEE has written a standard for battery monitoring called “IEEE Guide for Selection and Use of Battery Monitoring Equipment in Stationary Applications” IEEE Std 1491.
Another reader wrote in regarding my point that mixing batteries of different ages or internal resistances can prompt batteries to die more quickly. George Pederson, the business development manager at Rockaway, N.J.-based battery monitoring company BTech Inc. said that doesn’t mean you have to replace the whole battery string whenever one battery needs replacing. He elaborated:
This is not true, it is not the new battery that unbalances the string, it is typically because the battery unit that failed was not identified sooner and it had already done the damage to the other units. There is one caveat to that and that is, the replacement unit has to be fully charged a lot of times the service company will simply take a unit straight from the battery manufacturer and put it in service without a refreshing charge to ensure that the unit is fully charged and this will result in an unbalanced string.
Quite simply if the job is done correctly there is no reason why users shouldn’t get the full five years from a high rate battery.
Thanks to both Jim and George for writing in.