Re:Cascading UPSs

Jan 07, 2025 0 Replies

Don Y snipped-for-privacy@foo.invalid Wrote in message:r



I've a shitload of UPSs -- most in the office.Power *tends* to be pretty reliable, here, so they aren'tused for their "backup" capability. However, we do tend tosee "switching transients", predictably, at certain timesof the day. So, having a "second" of carryover is oftenhelpful (on the smaller machines; the larger ones have bigenough power supplies that they can bridge these momentaryoutages)Instead, they tend to be "outlet multipliers" in much thesame way as outlet strips might be (though a better formfactor, given the layout of my kit). They let me connectall of the devices for a host to the UPS associated with thathost. Then, power them all on/off at the same time.But, most importantly, it lets me get a feel for how muchof a load I have on the mains -- so I don't carelesslyadd some new load that blows a breaker!Replacing batteries is a costly -- and time consuming -- exercise.A single "shared" battery would be the preferred solution. But,not possible with COTS UPSs (nor the associated IR drops).OTOH, I *could* plug more than one UPS into a single (or few)"master" UPS that effectively takes on the role of the mainsconnection. Then, I just have to keep that/those UPS running("properly") to gain the benefits of bridging those brief glitches.Any downsides to this? If I remove the batteries from the"slave" UPSs (i.e., don't replace them when they fail), thenI can avoid that maintenance issue but still retain the otheradvantages of the UPS-per-workstation.Or, maybe put some trivial "power source" in their place thatis just enough to satisfy the UPSs' expectations of a "battery"?[I'd still have to put up with the "connect battery" messagesbut maybe I'll hack the firmware to "fix" that issue -- and,stop the silly scrolling of "screens" so I can just see thedata of interest, constantly.][[UPS manufacturers seem to have s***ty/buggy/unfriendly software]]

Just put a smaller battery in them, have done it myself as a last ditch effort to keep the ups running.


Cheers

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