Hacker News new | past | comments | ask | show | jobs | submit
The external sync here is NTP. Synchronized clocks + timer-scheduled actions → globally synchronized behavior

From the article:

> The origin of these current peaks was independently confirmed by the manufacturer to be periodic self-tests executed by the battery EMS, confirming our interpretation. Similar minute-scale diagnostic routines are also documented for other commercial UPS systems (cf. Supplementary Note 8).

https://www.snaptec.com.au/akkutec-4801-din-user-manual.pdf

> battery circuit testing 1 x per minute for 1 sec

https://adelsystem.com/hubfs/PDF%20DC-UPS/Instruction%20Manu...

> The battery testing is carried out automatically every 60 sec.

So, the two devices you refer to have no time-of-day clock, no network connection, no TCP/IP stack, and certainly no NTP clients.

Their testing on the enterprise-class equipment shows the difference that NTP makes, and with enterprise-class equipment comes wider deployment and more powerful models.

But most of the consumer units would not have this stuff. Surely, the manuals would describe how to set it up.

loading story #50327752