If you asked me this morning, I probably would have given you the standard APC answer.. between 3-5 years.
However, I realized that we actually have records to finding out what our customers have experienced. So I took our last 50 or so replacement battery orders and looked to see order date compared to purchase date. While our data wasn’t perfect, I did manage to get 25 or so direct data points. Once I plotted the differences, I noticed it averaged about 35 months. (see caveats)
Factors Affecting Runtime
Batteries have a certain amount of charge cycles before they go bad under normal operations. If your unit frequently uses the batteries, then your lifetime will be shorter. Most SmartUPS type units use the battery for outages AND power disruptions. So, even if you never have an outage your batteries may age faster if they are used to condition the power. One tip is to lower the sensitivity or the range of acceptable voltage.
The warmer the battery environment, the lower the lifetime. We change our batteries in our server room every 24months because our server room is in hellish hot Florida which is 90 degrees. Dont be like us, and keep your room cool and more importantly… give the UPS some air circulation.
Finally my favorite… Dont perform runtime calibrations too often. We had one customer that liked to do it each month as a way of checking on the UPS. Use the self-test feature instead
A few caveats: 1) Our plot shows time between purchase and replacement, it does not always mean the batteries had died when the customer repurchased them. 2) we recently started sending reminders to people starting on the 30th month about battery changes, so several orders were probably changed before they died. 3) I plotted one point for each customer, as several customers changed several systems all at the same time, which would skew the average. 4) We don’t do a lot of battery replacements, we mostly focus on our customers with service plans and higher VA units. 5) I started to plot the unit with the battery change, but the small sample size isnt large enough to draw fair conclusions about brands and models.