Re: UPS [Was:Re: Grand Apagon - Electricity (not) in Spain]

On 2025-05-09 02:13, Don Y wrote:

On 5/8/2025 7:18 AM, Martin Brown wrote:

On 08/05/2025 14:41, Carlos E.R. wrote:

On 2025-05-08 14:44, Carlos E.R. wrote:

>

UPS Topology: Standby (Offline) or Standby (Offline)

>
{Phrase translated by DeepL, so inconsistent: Topología UPS: En espera (Fuera de línea) o Standby (Offline)}

>
There are (at least) two major UPS topologies in play.
>
One is where the power to the protected device is always made by the inverter and maintained at the correct main voltage irrespective of input voltage to the UPS. Useful in places where the local mains supply voltage goes up and down a lot depending on load.

 These are usually called "double conversion" (some call them "online"
but that can be misleading).

Yes, I have seen that name, online, on some units.
The DeepL translation is not good. The vendor said "on wait (out of line) or Standby (Offline)", the second part in English. Probably a translation itself. I'm thinking the "or" is because they used "Spanish term or English term"

 Most of these (that I've encountered) are less efficient (cuz they
are always in-the-loop) and often won't START without a functioning battery.

Right.
At a telephone exchange I found one "online" UPS cascaded from an "offline" UPS, IIRC. Used on the control room hardware (displays and printers).

The other is a pass through of input mains voltage to the load under normal conditions and an isolation relay plus cold start of the inverter within a couple of cycles of the supply failure. This is more than good enough for PCs. Mine can withstand a 1s blackout unprotected without any difficulty but kitchen white goods clocks cannot.

 These often can do some line voltage adjusting with an autotransformer
"for free" (part of the design).

Yes, I have seen this. The house goes slightly "brown" and the UPS becomes active, I hear the clack of the relais and the buzz of the transformer.

 They, also, are available in models that can be started only with a
valid battery or not.  Some require mains voltage to be present, as well.

Right, they call this "cold start".

There are also cheaper units that use "stepped" waveforms to approximate
a sine wave; others that are more religious in their determination.

This is more difficult to find from the specs. Price could be an indication.

 

I do not see a reference to that "topology" except at the vendor. But it says that the expected battery life is 4 years.

 Ask for a guarantee on that... :>

Hah! The warranty is two years :-D
However, I do have another unit from this brand, and the battery did last longer. This particular unit uses two batteries, 24 volts, actually.
Usually, I stick a label outside where I write the date when I replace the battery, and the price, but on this particular UPS I don't see the label. So I don't know the actual duration. Maybe I put the label inside?

 [ObTrivia:  SWMBO's vehicle needed a starting battery replacement
~3 years after purchase (battery life is about that for all vehicles,
here; the heat cooks them).  As that was within the ~5 year "factory
warranty" period, it was no charge -- so I didn't bother to get
involved!
 THAT battery, of course, failed 3 years later.  But, as it was
considered part of the original vehicle (despite being a replacement),
there was no warranty extended to it.
 So, I went to Costco and bought one to avoid the dealer's insane
charges!]

That's funny. My car battery is currently 6 year old, and going fine, according to the garage (they just checked it). There was some "sulphate" on the lead stud which I told them to check.
And here it is hot weather, for about 5 months a year. :-?
--
Cheers, Carlos.