On 10/22/2022 11:19 AM, Ed Lee wrote:
>>>> Maybe there's more to the technology than you think!
>>>
>>> Not really. I don't care what kind of battery charge management the UPS has,
>>> the replacement battery can be made to look identical to the original.
>>> Cutting off the charge current in float mode does not mean opening a relay
>>> switch or something crude like that. The replacement battery can present
>>> enough of a self-discharge current loading to make itself look real enough.
>> And, you'll discover on one UPS the UPS won't turn on because it doesn't
>> see a battery; on another, it won't run it's self checks; etc. You don't
>> know what "firmware A" expects of it's battery that "firmware B" doesn't.
>>
>> All of the battery-backed products I've designed predated lithium. Put
>> a lithium battery in them and they'll throw a fault -- because the
>> battery isn't discharging at the expected rate; or is charging at
>> the wrong rate (dv/dt); or, the monitoring circuitry appears defective; etc.
>>
>> "Hey, let's make this lithium battery look EXACTLY like a lead acid -- so
>> it HAS NO ADVANTAGES over a lead acid battery! But, we can charge more
>> for those non-differences!"
>>
>> MSRP $1,865.88 <
https://www.amazon.com/dp/B08QQRFQ4W>
>> MSRP $2,899.99 <
https://www.amazon.com/dp/B09JR6ZCQX>
>
> 1500VA or 100Wh? See first comment. That's certainly expensive. I can get 100Wh for $28.9999
1500VA load capacity. Run time (for each) is 5 minutes at full load
(about 13 minutes at half load -- though the lead acid unit will go
almost 15 minutes). I have several of the first unit that I use
to power my "bench tops" (anything located *on* my bench vs. UNDER).
My point is, they could have taken the existing LA design and just
put lithium batteries in it, if there was no other consequence to
changing the battery chemistry. After all, they allegedly "look
just like lead acid", right? :> And, other than longevity and
power density, they offer no better *performance* in this example
(in practical terms: run time!)
My experience (processing LITERALLY *thousands* of discarded UPSs
that are still operational -- except for their batteries) has been
that folks think they need a UPS. And, later, decide they aren't
worth the trouble. Mains power, in most places, is pretty
reliable. Outages infrequent. And, systems (except life support)
tend to be reasonably robust in limiting loss due to abrupt
outages.
[Think about it; do you really do any work during an outage?
This machine -- and the modem -- have an oversized backup
that will keep them operational for a couple of hours. But,
every other machine just needs to stay "up" until I can get
around to noting what they were doing, at the time of the outage,
and cleanly shutting them down -- before the UPS daemon does
that unilaterally]
Most of the 12 (15?) UPSs that I have here were rescued NIB;
many with functional battery packs (some happened to have been
warehoused too long before being discarded). Anything with bad
batteries has a (recycle) value of about $5 -- largely for the
weight of the switching transformer (plastic has NO value and
the tin/steel case is $0.01/pound; circuit boards have very little
precious metals so pennies, there).
[An unattended workstation is typically idle and the disk cache has
already been written out so you're only concerned with outages
WHILE you are actively working on something.]
Hence my points to the OP. Think about WHY you are looking at lithium
pack replacements (they are roughly double the price of lead acid;
is the inconvenience of replacing them every three or four years
really worth the price? Are you sure you won't be replacing (or
discarding!) the UPS in that same interval??
[I see a market for oversized "super caps"; temporary energy reservoirs
to let UPSs ride out very short outages -- a second or two -- without
the need for replacement]