Above: UPS in action. Photo by Mark Lyndersay

BitDepth #1318 for September 06, 2021

Last week, electricity was cut four times, each instance for less than a minute, where I live and work in St James. TTEC later issued a notice about load-shedding.

Over the years, I’ve also lived with a quiet clicking on my desk, indicating that the uninterruptible power supply boxes (hereafter, UPS) that protect my computers are either evening out power sags or the battery has kicked in to manage an under-voltage situation.

There are many things that can go wrong with your electricity supply and the pandemic has dramatically changed how power is consumed in Trinidad and Tobago.

If you’re working from home, you may have a company-supplied computer, but you don’t have their IT support systems, which normally would include power outlets protected by an powerful enterprise-class UPS.

There are some things that a UPS is not. It is not a power supplement, like a battery pack that you can use to recharge or power a smartphone or tablet that’s low on power.

It is not an emergency power system like a gas-powered generator, which gives you access to AC power when electricity goes.

A UPS sits between your computer and the power outlet and acts as a buffer between the electrical requirements of your system and T&TEC’s capacity to supply power.

UPS boxes are used widely throughout the world because computer systems are sensitive to the quality of public electricity supply.

The dynamics of power generation favour quantity of supply over quality, because most people just want a consistent supply of electricity and aren’t as concerned about power levels as long as their lights don’t get too dim.

Sometimes the supply is adequate, but local demand can wreak havoc on power loads.

Transformers where I live here in St James, the large drums that you’ll find attached at the top of utility poles, explode in a shower of sparks with alarming frequency, taking down power supply to sectors of the community.

This happens in any town with significant business growth, which places greater demand on supply leading to sags and variations.

Businesses with high electricity demands are supposed to pay TTEC for a dedicated transformer, but it’s expensive, and some don’t bother.

Computers in particular are quite fussy about power quality and variable power input can take an incremental toll on hardware that remains invisible until it goes terminal.

There are three ways you can protect a system from variations in electricity supply.

A surge protector is designed to take the hit from a sharp spike in electricity coming down an electrical line. When it does that, it burns out.

That’s much less common than it was here in Trinidad and Tobago, but special high-voltage surge protectors are the only protection option for power-hungry appliances like laser printers, refrigerators and laundry washers and dryers that have electrical loads that are too great for a UPS.

Line conditioners even out variable incoming electricity. They manage both power levels and the harmonic waveforms of the electricity supplied by a power outlet.

I used a couple of these boxes in my darkroom between 1980 and 2000 to improve the consistency of output from enlarger lamps.

A good UPS bundles these features and adds another, a battery backup that can give you a chance to close your files and shut down your system.

For a computer tower with a hefty power draw, it’s probably a good idea to have a specialist analyse your needs to find out how much battery backup you will need to give you enough time to shutdown.

I use a tower system for a server that runs for around ten minutes on a 1500VA battery, but the monitor for it is connected to another UPS.

Laptops and tablets will be less demanding, drawing lower power than a desktop system and can run on their own batteries for a while.

Internet connections, inclusive of a modem and WiFi router, are also power stingy, but often must run for a longer time.

All UPS systems have a battery backup, but they are not equal.
Everything less than 1500VA in capacity is either a standby system or a line-interactive unit, which has its own transformers and delivers higher power output.

Double-conversion systems are the pinnacle of UPS aspirations, turning incoming AC power to DC battery-stored energy and then converting it back to AC for connected devices. Those devices only get pure, consistent electricity, but prices are daunting for individual users.

Lower voltage UPS options may look like hefty power extension cords, but you should go directly to a tower box.

You will need more battery capacity than you think and while the plugs are placed rather annoyingly at the back of these units, most will allow you to turn off the alarm that signals that the battery is in use.

That’s particularly important in a work from home environment because there are enough distractions without the insistent beeping from a UPS in the dark adding to your desperate effort to meet a deadline.

UPS safety

• Always clear a space for your UPS that’s properly vented and close to a wall socket.

• Never plug a UPS into an extension cord. It must always be plugged directly into a wall socket.

• Fully charge a UPS before use. Test loads by connecting devices and unplugging the UPS.

• Take a moment to understand the panel on a tower unit. There is a lot of useful information about the quality of your power supply in the numbers it reports.

• In typical use, a UPS battery will last around three years, expect to pay around half what a new unit costs to replace the batteries.

• Dust is the enemy of UPS systems, diminishing cooling efficiency, so if possible, keep them off the ground.