So it’s loadshedding season, and I’ve decided to learn a bit more about the UPS game. That’s the dream, isn’t it? Being able to work (or play, or watch) through the loadshedding, completely uninterrupted?
To that end, I decided to start small, and get an idea of what UPSes are capable of. I bought the smallest one I could from newly-launched Powerfully.co.za – a Mecer 650VA Offline UPS. The experience there was stellar: I placed the order, paid online, and received it (in Gardens, Cape Town) the very next day. It even had some charge in it, and I got to annoy the office with the every-10-second beep it makes when there’s no AC power. Note: The Mecer UPSes use kettle plugs, and the one I got did not ship with a plug I could stick into a wall. Not an issue for most computer users (everyone has a kettle plug lying around these days), but if you have none, you may one to order one along with the UPS.
I got an Offline UPS, and if you’re browsing around, you’ll note there are Offline (or Line Interactive) and Online UPSes. The difference (other than cost) is the changeover time. Offline UPSes use a mechanical switch to flip you over to UPS power in the event of an outage, incurring a delay anywhere from 5-25ms. That’s fine for most consumer electronics, but if you have something that absolutely cannot go down, an Online UPS is a better bet – it doesn’t do any switchover, so there’s no delay.
My setup is pretty basic. I know that, with a 12V 7Ah battery, there’s no way to feed my beast of a desktop PC (650w power supply!) for any appreciable length of time, so instead, this is my setup:
- Mecer 650VA UPS connected to the wall
- Power strip plugged into the back (it has a regular 3-pin socket)
The router uses minimal power, in the 1.2A range – and the Chromecast uses about the same. The TV is a different story. At peak consumption it can draw up to 100W, but I managed to cut that in half using the energy-saving mode (Medium) on the TV. You can go to Maximum, but then it drops the screen brightness by about 80%.
With this setup, my WiFi is guaranteed – the Telkom line does not go down when there’s loadshedding, and all my gadgets connect over WiFi, so at least I have uninterrupted internet. The TV was just to give it a proper stress test. That test was monitored with the supplied software – I installed it on a Windows laptop and plugged the USB cable into the UPS to get some information from it. It’s pretty, simplistic, but ultimately not very useful:
The UPS comes with a very annoying audible alarm, which sounds every 10 seconds when the Eskom AC power is down. Thankfully, you can disable that (in the Real Time section), and that’s about all the software is good for. The battery indicator is notoriously unreliable, as I’ll get to in a minute.
I set up a stress test by leaving the UPS plugged in and charging for 24 hours. Then I cast a Youtube HD clip to my TV (StarCraft 2 finals – constant audio and visual output), ensuring that all 3 devices were active. Then I flipped the switch on the wall, and it went into battery mode with an audible click. None of my devices noticed the drop – WiFi stayed up, TV stayed on, Chromecast kept streaming.
These were the readings over the duration of the test:
- Start: 100% capacity
- 2 minutes: 68% capacity
- 3 minutes: 72% capacity ( go figure )
- 30 minutes: 48% capacity
- 38 minutes: 15% capacity
- 41 minutes: 2% capacity, battery died
The reporting was wildly inconsistent. The battery “drained” 30% in 2 minutes, then took 30 minutes to drain another 30%, and then finished off the rest in about 10 minutes. The only reliable indicator was the lights – the red light comes on, and the yellow light flashes frantically when the battery is about 2 minutes away from death.
This does mean, though, that a R670 UPS was able to keep a 42″ LED TV operational, streaming HD content, for a full 40 minutes. Which is not bad for a device meant mainly to give you enough time to safely power down your computer.
In reality, all it’s going to power is my router, TV in standby mode (0.3W draw – neglegible) and an idle Chromecast. It should be able to do that for far more than 40 minutes, which will be my next test.