Has my UPS died?

[BillP]

This question was originally posted by Gareth on APC forums on 6/1/2016

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I have a SMT2200i that is coming up for 6 years old, the battery pack died after 4 years, the replacement pack failed a test a year in so it has just been replaced again. I put the multimeter on the front battery pack and it read about 26 volts, plugged it in and (again as this happened  last time) I got  a  event code 149 Charger Overvoltage   that refused to go away after a brain dead. (tried about 3)

In the end I let it run on battery for a while and it took the voltage down to 24 volts, I connected the mains and it stayed at 24v even though it said it was now charging. The voltage didn't climb at all during this time from 40 to 80%. (it does this voltage connected or not)

I pulled the mains and discharged the batteries until the front pack read 20v, once the pack was pulled it inched back up to 23.6v and stayed there despite it charging form 0% to 80%

I just ran a calibration that lasted under 10 minutes from a supposed 100% charge (it said about 70% before I pulled battery and mains to have a look inside for anything obvious)

It is now at 31% still showing the battery at 54.8v when the multimeter (an accurate one) reads 47.3v when I take a reading inside from the battery connections.

So it is reading 6v out and I expect this is part of the problem.

I take it I will have to scrap this?

[Terry_Kennedy_apc]

This was originally posted on APC forums on 6/2/2016

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Did you measure the 26 Volts at the same place you later found 47.3V? Some newer models (I'm not familiar with yours) have the battery string split into 2 or more groups, so this might be possible. But from the same pins on the same connector - I'd say something is wrong. Were these real APC replacement batteries? There's nothing wrong with using other batteries if you know what the trade-offs are, but an APC RBC will have a serial number sticker with an embedded date code xxYYWWxxxxxx where YY is the year of manufacturer and WW is the week of the year. I'd expect to see a battery pack less than 4 months old when purchased through an authorized reseller, as un-recoverable loss of run time will set in at around 6 months of storage. And APC RBCs (for any other than the single-battery ones) come with the whole wiring harness pre-installed, so you don't have to worry about mis-connecting new batteries.

Having said that, my experience (with older, non-LCD Smart-UPS models) is "3 years on original batteries, 2 years on the first replacement set of batteries, then less than 1 year on any future replacements". That's without re-calibrating and other internal maintenance that APC won't provide information about.

The bigger series (discontinued Matrix-UPS, current Symmetra, and possibly the HVDC battery bus Smart-UPS units) will keep going forever. I have a 19-year-old Matrix 5000 and a 15-year-old Symmetra RM still going strong, with only occasional battery replacement and fan replacement as needed.

[BillP]

This reply was originally posted by Gareth on APC forums on 6/2/2016

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Batteries are as genuine as they could be considering they are RMA's  direct from Schneider that have been on back order so as fresh  as the come due to being new stock! 🙂

I took the individual voltage from one group then the combined voltage across both to see what was really  going on.

When it 1st powers up it spikes around 55v as though it is going to charge  then drops straight down to match the battery voltage within a second (using the multimeter, basically what is contained in the capacitors.

I wish I knew what the charging circuit was and how to diagnose the issue although it seems to be related to the voltage mismatch (nearly 8v higher than it is) so I assume the smart charging kicks in and stops charge.

[MarkC_apc]

This was originally posted on APC forums on 6/2/2016

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If you have access to a network management card, it would be interesting if the logged battery voltages match your voltmeter or the LCD screen.  It does appear the unit's "brain" is malfunctioning as I've never seen more than a few tenths of volts difference in the logged voltages (NMC logging) vrs a good digital voltmeter.  I guess it's possible you have a bad connection somewhere in your DC circuit between the batteries and mother board?

Assuming you have four 18AH batteries, all batteries (nominal 12 volt) should be about equal voltage when operating under load - if any substantial difference indicates a potentially bad battery.

[BillP · Accepted solution]

This reply was originally posted by Gareth on APC forums on 6/2/2016

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Thanks, like I said, new batteries installed. It seems the ones that went back were also good. I took the liberty of cleaning the battery plugs with a dremel  polisher to remove any signs of arching as well, it didn't help.

The NMC logged 54.78 when they are now 47.2

Anyway, some chap on eBay had a brand new one he bagged at an auction for lost parcels so I have one sat here charging now after striking a deal and driving 60 miles to his house. It had never been turned on and I phoned Schneider this morning to check the serial for warranty reasons. 

So all is good!

New ones showing 54.5 on the NMC and 54.47 on my DMM  if I double the voltage of the 1st battery pack 🙂

Wish I knew what to do with the old one as I would love to figure out the fault.