In all of the large telephone switch CO's I've been in the 48v battery bank was WET cells.
I think the "gel cell" was a marketing triumph. In one fell stroke they replaced a wet cell that would normally have a useful lifespan of 5-6 years with the same technology that has a lifespan of half that - so you are replacing batteries twice as fast. It's why I don't use the AGM glass mat batteries as starting batteries in my vehicles. Ted -----Original Message----- From: PLUG <[email protected]> On Behalf Of Chuck Hast Sent: Saturday, June 13, 2026 7:19 PM To: Portland Linux/Unix Group <[email protected]> Subject: Re: [PLUG] hammered by sudden UPS power failure during a key backup When I worked in the glass container industry dealing with inspection machines, each machine had an internal sine wave APC UPS or a Tripp Lite rack mount UPS installed. The batteries were replaced religiously every 2 years. We did not worry about checking the batteries we just replaced them, never had a power loss, When I was at the Kalama plant we did have one UPS failure but it was not due to batteries. The UPS failed off line but kept mains power on the affected circuits so we were able to do a proper shutdown and swap it out. I think with lead acid you are better off doing the change out by time. On Thu, Jun 11, 2026 at 1:37 AM Ted Mittelstaedt <[email protected]> wrote: > Hi Randall, > > Through long experience I have found that only the original Lead Acid > AGM or Gel Cells that come in a brand new UPS have anywhere close to 5 > years in them. Any time I have replaced a set of these in a UPS no > matter how much money I have spent on whatever kind of batteries I've never > gotten 5 years > again. At most it's been 3 years. Sometimes 2 years. Maybe the Lithium > batteries are going to be better but those UPSes are too spendy for my > budget, yet. > > Now, the "textbook" answer from APC is that their SmartUPSes have a > "calibration mode" The way this works is, you put a set of fresh > batteries in an SmartUPS. Then you let them completely charge for a > day or so. Then you run a calibration test from the control panel of the UPS. > The test puts the batteries under load and starts a clock and then > starts checking the voltage of the batteries. When the battery > voltage drops below 11.2 volts or some such then the test stops. The UPS > then "learns" > the battery's "discharge curve" and changes a calibration factor. The > factor allows the UPS to tell how long the battery is going to last > when put under load. > > The SmartUPS then weekly self-tests the batteries by putting them > under load for a few seconds. Based on what level the battery voltage > drops as a result of being put under load the UPS is then supposed to > be able to predict how long the batteries are going to last in a real > blackout. > > When the batteries are a year old then you are supposed to run a > calibration test again which figures out if the calibration factor > needs to be changed. > > Now, I do not know if this testing by APC is really able to predict > how long an actual battery lasts or whether it's snake oil. > > The articles I have read on lead acid batteries all seem to say some > basics. First point is that if the battery is overcharged then the > electrolyte starts boiling off the water. (ie: converting the water > into free hydrogen and oxygen) With a car starting battery this is > not a problem since if you just check the electrolyte level and keep > the battery topped off, then you are fine. With a sealed lead acid > battery then the electrolyte paste has some magic chemical in it that > supposedly "recombines the hydrogen and oxygen back into water" > > The second point is that temperature matters greatly. Here is the > output of apcupsd from my 14 year old SmartUPS: > > root@officeserver:/usr/home/tedm # apcaccess > APC : 001,042,1055 > DATE : 2026-06-10 22:29:42 -0700 > HOSTNAME : officeserver > VERSION : 3.14.14 (31 May 2016) freebsd UPSNAME : APCUPS > CABLE : USB Cable > DRIVER : MODBUS UPS Driver > UPSMODE : Stand Alone > STARTTIME: 2025-12-17 05:22:44 -0800 > MODEL : Smart-UPS 1500 > STATUS : ONLINE > LINEV : 120.9 Volts > LOADPCT : 29.2 Percent > LOADAPNT : 22.7 Percent > BCHARGE : 100.0 Percent > TIMELEFT : 56.0 Minutes > MBATTCHG : 5 Percent > MINTIMEL : 3 Minutes > MAXTIME : 0 Seconds > OUTPUTV : 120.2 Volts > DWAKE : 0 Seconds > DSHUTD : 0 Seconds > ITEMP : 27.0 C > BATTV : 27.2 Volts > LINEFREQ : 60.0 Hz > OUTCURNT : 2.75 Amps > LASTXFER : Automatic or explicit self test NUMXFERS : 7 XONBATT : > 2026-06-03 07:45:32 -0700 TONBATT : 0 Seconds > CUMONBATT: 46 Seconds > XOFFBATT : 2026-06-03 07:45:41 -0700 > LASTSTEST: 2026-06-03 07:45:33 -0700 > SELFTEST : OK > STATFLAG : 0x05000008 > MANDATE : 2012-11-03 > SERIALNO : AS1244115771 > BATTDATE : 2023-12-14 > NOMOUTV : 120 Volts > NOMPOWER : 1000 Watts > NOMAPNT : 1440 VA > FIRMWARE : UPS 15.0 / 00.5 > END APC : 2026-06-10 22:30:23 -0700 > root@officeserver:/usr/home/tedm # > > You will notice that there is an internal temp there. This is because > this model of UPS has an internal temperature sensor. You will also > notice that 27C is at the top upper limit of ideal operating > temperature. This model of UPS has 100% steel case and this > particular UPS is sitting on the concrete floor of my basement so it's > as cold as it can get yet there's still heat in the UPS. > > You will also note that the battery date is 2023. This is because > when I last changed the batteries in this UPS I configured that date > into the NVRAM of the UPS. > > You will note the load % is about 30%. This is around the minimum amount > of load needed for an adequate self-test. Too little load and the UPS > will not be able to drain the batteries at all during a 3 second > self-test and thus will not be able to get usable data regarding the battery. > > You will also note "timeleft" is 56 minutes. > ] > I think that it is probably not possible for a 3 year old sealed lead > acid battery set to power a 2.75 amp load plus the inverter power loss > for an hour. The ridiculous timeleft, the excessive heat, really > point to the beginnings of thermal runaway. These batteries are close > to the end of their life - even though the UPS self test has NOT > caught this yet. They now have significant internal resistance and are > generating excessive heat > in the UPS I should replace them. > > Ted > > -----Original Message----- > From: PLUG <[email protected]> On Behalf Of American > Citizen > Sent: Wednesday, June 10, 2026 5:37 PM > To: [email protected] > Subject: [PLUG] hammered by sudden UPS power failure during a key > backup > > To all > > I am struggling to recover from a very bad power failure during a key > upgrade from my OS openSuse Leap 15.6 to Leap 16.0 upgrade. > > My UPS unit completely clicked off right during the backup. > > It has been several hours now and I am trying to carefully pick up all > the pieces and verify that I did NOT lose any data. > > My question to all of you is simple: > > How can you tell the health of the lead-acid batteries in your UPS unit? > From what I can gather, this cannot be done live via any linux operations. > > My lead acid batteries were shot, and bulging out their case. > > Yes I was aware that I had 5 years time on these back up lead-acid > batteries and was risking total failure, which actually occurred this > afternoon for me. > > How do you keep on top of the UPS units so you don't have a rather > foolish incident like mine today? > > Randall > > p.s My unit was the Cyberpower CP1350AVRLCD (see > https://www.cyberpowersystems.com/product/ups/intelligent-lcd/cp1350av > rlcd/ > ) > > > > >
