APC Back-UPS Pro 650

The Back-UPS Pro 650 is a sleek line
interactive UPS, which performed well in our tests. It has an operating voltage range of
159-283 V, which is good for Indian line conditions where wide voltage variations are the
norm. The UPS has good AVR (automatic voltage regulation) too, which keeps the output
voltages between 208 to 252 V.

The switchover characteristics of the
UPS are very good. It switches to battery in less than 4 ms, and provides adequate voltage
during this period to make it a safe switchover.

We tested the backup capability of the UPS
with different loads. It gave a whopping backup of 53 minutes to a single Pentium 133 with
a 14" monitor. It gave a backup time of 11 minutes to a load of two Pentiums and one
PII machine with 14" monitors. This is approximately 50 percent of its rated load. On
80 percent of its rated load, it gave a backup of 6 minutes. This is enough time for a
safe shutdown.

We also tested the UPS against frequency
variations when power is supplied through a generator. It can tolerate frequency
variations of +/-5% of 50Hz, which is just about good enough.

The UPS’s float voltage (the voltage
across the battery terminals when the battery is fully charged) is high at 2.32 V. The
ideal value should be between 2.25 to 2.29. Any value above or below this eats into
battery life. The UPS has a single battery that can be easily removed for replacement.
It’s also programmed to do a self-test when it’s turned on to warn you of a weak
battery. This is indicated by an LED on the front panel. There are three other LEDs to
indicate overload, online, and switchover to battery.

Besides these the UPS has telephone line
protection ports which protects it from spikes and surges, when modem is connected to your
PC. There’s also a separate port with surge protection, which doesn’t give any
battery backup. This can be used for connecting less critical peripherals like laser
printers that don’t really need backup. There’s also a push-button recovery
circuit breaker, which saves you from the hassle of changing fuses. The UPS comes with
good power management software for automatic and scheduled shutdowns.

The UPS’s price makes it unsuitable
for one-PC use. It’s good for small workgroups consisting of three or four machines,
output then being enough to just save the work and shut down.

The UPS comes with 2-year warranty. Though
it’s good in performance, it’s priced a bit high (the price given excludes tax
also). If the software was made optional, and the price reduced, this would be a great
buy.