With winter comes the risk of power loss to the facility due to heavy snows, ice storms, or excessive cold. Facilities with emergency systems and critical processes typically install a battery backup. Just having a battery backup isn't exactly the same as protecting against power loss, but good execution of battery monitoring can make them effectively the same thing.

Bart Cotton, a battery monitoring consultant, is fond of saying that you need someone to monitor your battery monitor. That someone needs to understand what the monitor is saying and what to do in response. Otherwise, Cotton wryly notes, “It's just a wall ornament.”

You may recall from your holiday turkey a few weeks ago that a little “it's done!” gadget pops up at a predetermined temperature. Unfortunately, battery monitoring isn't quite that simple. Although some alarms and alerts will tell you it’s time for corrective action, you can't assume the batteries are fine if they don't. Nor can you rely on “single-point-in-time” measurements.

A voltage that's high for one battery string may be normal for another. Do you know what's normal for the battery string you’re looking at? Are you plotting the data points properly? Can you differentiate a statistically acceptable variance from an actual problem? In our next issue, we'll explore this further.