I've a shitload of UPSs -- most in the office.
Power *tends* to be pretty reliable, here, so they aren't
used for their "backup" capability. However, we do tend to
see "switching transients", predictably, at certain times
of the day. So, having a "second" of carryover is often
helpful (on the smaller machines; the larger ones have big
enough power supplies that they can bridge these momentary
outages)
Instead, they tend to be "outlet multipliers" in much the
same way as outlet strips might be (though a better form
factor, given the layout of my kit). They let me connect
all of the devices for a host to the UPS associated with that
host. Then, power them all on/off at the same time.
But, most importantly, it lets me get a feel for how much
of a load I have on the mains -- so I don't carelessly
add 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 mains
connection. 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), then
I can avoid that maintenance issue but still retain the other
advantages of the UPS-per-workstation.
Or, maybe put some trivial "power source" in their place that
is just enough to satisfy the UPSs' expectations of a "battery"?
[I'd still have to put up with the "connect battery" messages
but maybe I'll hack the firmware to "fix" that issue -- and,
stop the silly scrolling of "screens" so I can just see the
data of interest, constantly.]
[[UPS manufacturers seem to have shitty/buggy/unfriendly software]]
On 07-Jan-25 5:22 am, Don Y wrote:
OTOH, I *could* plug more than one UPS into a single (or few)
"master" UPS that effectively takes on the role of the mains
connection. 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), then
I can avoid that maintenance issue but still retain the other
advantages of the UPS-per-workstation.
Or, maybe put some trivial "power source" in their place that
is just enough to satisfy the UPSs' expectations of a "battery"?
Some UPS designs cannot be turned on[*] without a battery in them, even when supplied with mains power, because they cannot energise the relay that enables
the mains connection.
[*] They can stay on, just not be turned on.
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
Just put a smaller battery in them, have done it myself as a last
ditch effort to keep the ups running.
On 1/7/2025 4:27 AM, Sylvia Else wrote:
On 07-Jan-25 5:22 am, Don Y wrote:
OTOH, I *could* plug more than one UPS into a single (or few)
"master" UPS that effectively takes on the role of the mains
connection. 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), then
I can avoid that maintenance issue but still retain the other
advantages of the UPS-per-workstation.
Or, maybe put some trivial "power source" in their place that
is just enough to satisfy the UPSs' expectations of a "battery"?
Some UPS designs cannot be turned on[*] without a battery in them,
even when supplied with mains power, because they cannot energise the
relay that enables the mains connection.
Hmmm... I've found devices that can't be powered on in the absence of
MAINS voltage (which, IMO, is an annoyingly arbitrary constraint...
suitable for discard). But, all seem to power on without a battery (assuming mains voltage is available) though may "complain" about the
fact.
These have the annoying habit of persistently displaying "Connect Battery" message -- which can't be dismissed (in favor of the other status
messages).
[*] They can stay on, just not be turned on.
In fairness to UPS designers, having the UPS able to start without a battery is
an edge case they probably wouldn't have felt was important.
I had an old UPS (sadly, now long dead) that behaved this way. The battery side
was completely isolated[*] from the mains by a transformer, which allowed hot-swapping of the batteries (a feature described in the manual). But this was
the same transformer as was used to generate the output voltage. Consequently,
they had to ensure that there was no danger of back feeding the mains, which rather precluded relays whose default position was to connect the mains.
Mind you, they also included an expensive component whose sole purpose was to ensure that the mains wasn't connected during an outage. This was perhaps a level of over-engineering that goes to explain why they no longer exist.
Sylvia.
[*] Which was not the case for the more recent UPS I bought to replace the old
one.
Some UPS designs cannot be turned on[*] without a battery in them, even when supplied with mains power, because they cannot energise the relay that enables
the mains connection.
Sylvia.
[*] They can stay on, just not be turned on.
And, the home/SOHO markets have got to be "one time" purchases
Don Y <blockedofcourse@foo.invalid> wrote:
And, the home/SOHO markets have got to be "one time" purchases
The home/SOHO market is much more likely a "disposable appliance" where UPS'es are concerned.
They buy one. When the ear peircing continuous scream of "battery
gone" eventually occurs, they trash it and buy another new one.
A small subset that would be willing to swap the battery /might/ look
at the manufacturers cost for a replacement battery and then conclude
that it is cheaper to just trash it and buy the one on sale on Amazon
right now, because new battery for old unit is 110% the cost of the
sale item on Amazon. So those become disposable appliances as well.
It seems that the UPS makers must rely on battery sales for their
livelihood,
given the number of discards I find. And, they have virtually *no* recycle value (batteries are ~20c/lb and the rest of the unit is worth < $5 for the minimal electronics, transformer and steel case)
Don Y <blockedofcourse@foo.invalid> wrote:
And, the home/SOHO markets have got to be "one time" purchases
The home/SOHO market is much more likely a "disposable appliance" where UPS'es are concerned.
They buy one. When the ear peircing continuous scream of "battery
gone" eventually occurs, they trash it and buy another new one.
A small subset that would be willing to swap the battery /might/ look
at the manufacturers cost for a replacement battery and then conclude
that it is cheaper to just trash it and buy the one on sale on Amazon
right now, because new battery for old unit is 110% the cost of the
sale item on Amazon. So those become disposable appliances as well.
On 2025-01-08 07:05, Don Y wrote:
...
It seems that the UPS makers must rely on battery sales for their livelihood,
given the number of discards I find. And, they have virtually *no* recycle >> value (batteries are ~20c/lb and the rest of the unit is worth < $5 for the >> minimal electronics, transformer and steel case)
Some units kill batteries faster than others.
It happens when they leave them permanently charging, theoretically to 100%. Others fully stop the charger and leave the battery alone for hours. With this
method, unless there are mains failures, the battery last 5 years instead of 2
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