Absolute Power, Part 2

First, read Part 1

Now, on to Part 2. What many people don’t understand is that there are four major kinds of UPS units. We are going to talk about three – standby, line-interactive and on-line. Click here for details on all four.


The standby-ups is the lowest-cost, most commonly found UPS around. It works by directing the wall power to its outlets when the power is on. During a brown-out (power flicks off/on, goes bad etc.) or black-out (power goes off and stays off), a sensitive switch diverts power to the battery installed in the unit. It takes just a few milliseconds – which is no problem for most standard equipment most of the time. But occasionally, especially with some equipment, this can fail, either causing loss of power or damaging dips in power stability.

Currently (nice pun!), I’m using a small collection of cheap stand-by UPS and during rapid on/off power blips during a lighting strike, I had such a failure which took down my main storage server resulting in a couple of weeks of downtime. Fortunately, no data was lost and insurance covered the downtime, but still a bad situation.


The line-interactive UPS uses a combination inverter/converter to charge the battery backup, and convert DC to AC during a power drop. The advantage is that converter/converter is always supplying power, so switching between power company and battery power is much more seamless. Plus, line-interactive UPS’s use voltage regulation which handles brownouts, voltage and current spikes.

Some models also use microprocessor tech to further increase processing speeds and current cleanup. It’s a good sweet-spot for power user machines. They run about 50-100% more pricewise than a standby-UPS but well worth the upgrade.


The online UPS is exactly the opposite of the standby UPS. The connected systems are always on battery power as incoming power continuously charges the battery.  This means no switchover every occurs and systems get very stable, clean battery power always.

Of course, there’s a catch or two. Price is the big one, costing 2-3 times a line interactive model, putting them out-of-reach for many users. Additionally, they suffer another issue many people miss – noise. When a higher power UPS is running on battery, they usually require a cooling fan to run. Not an issue for standby-UPS or line-interactive models as you only hear the fan during an outage. But for online-UPS, it’s 24/7.


As you might guess, I’m going with line-interactive UPS’s for critical machines and standby-UPS’s for other components. An online UPS or two would be great, but price and noise (even when moved to another room) make them less than ideal choices. I looked at the lower end on-line models, but many suffered with very noisy, non-replaceable fans, low capacity etc. So I’m looking at CyberPower’s Professional line-interactive line. Not as nice as a Liebert or APC but a cut above the bargain guys.

That’s a theme you continue to find for this film – bang for the buck. The big guys can spend money like it’s nothing. But indie filmmakers have to carefully balance how much performance they can wring out of the fewest dollars possible.


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