I'm about to give up on the BQ16, Inconsistent WiFi speeds.

[nsayer]

The manufacturers started getting wise and figured a way to make them cheaper, hence lower price, by producing a simulated sine wave output. Similar to vehicle DC to AC inverters. I'm 100% sure it created noise and to this day that UPS just sits. (I got lucky because typically first thing I do is connect my new expensive router to a UPS which doubles as a surge protector, but this time I did some testing in my room and simply connected to a surge strip). If I can find an image of the crazy poor WiFi speed test I'll post it. But it was only obvious since I tried the surge strip first. For example download speed would be perfectly fine, but upload speed was roughly 10% of what it should be.

Here's the thing: any wall-wart made in the last 20 years is almost certainly a flyback topology supply.

The design of a flyback supply is that you start by rectifying the incoming power to DC. Then you switch that HVDC at a very high frequency to power a relatively small transformer. On the secondary you rectify again to make the LVDC output. A feedback circuit samples the output voltage to control the duty cycle of the switching on the primary.

That, essentially, is why all of them are labeled 90-250 VAC, 50/60 Hz. Because step one is to rectify to DC they don't really care very much about the quality of the incoming power, provided it averages higher than a minimum voltage.