Critical - UPS: At least one faulty battery exists - But which???

[mlewis_apc]

There are four battery packs in this unit, they were changed out only a few months ago yet I keep getting these warnings again.

Name     : Smart UPS 10000

Location : xxx

Contact  : xxx

https://APC10K.mydomain.com

https://192.168.1.253

Serial # : ZA0443007046

Device Ser #: YS0451110605 

Date: 04/20/2014

Time: 23:26:14

Code: 0x0119

Critical - UPS: At least one faulty battery exists.

	Smart-UPS RT 10000 RM XL: UPS_AZ     Replacement Battery Needed At least one faulty battery exists.   Self-Test Failed Failed a self-test.
	Quick Status   Load in Watts Battery Capacity   42.0 % 100.0 %     Input Voltage: 247.6 VAC Output Voltage: 208.2 VAC   Runtime Remaining: 21 minutes Last Battery Transfer: Due to software command or UPS's test control

[mlewis_apc]

Status
Last Battery Transfer:	Due to software command or UPS's test control
Internal Temperature:	95.3°F
Runtime Remaining:	21 minutes
Power
Input Voltage:	247.6 VAC
Output Voltage:	208.2 VAC
Input Frequency:	59.99 Hz
Load
Load Power:	42.0 %Watts
Apparent Load Power:	35.0 %VA
Load Current:	16.87 Amps
Battery
Capacity:	100.0 %
Battery Voltage:	214.9 VDC
External Batteries:	1

[BillP]

Hi again!

This UPS does not have "intelligent" batteries so which ones did you not replace last time? I forgot if you had external batteries, like an external SURT192XLBP battery pack or if you're just talking about the (2) RBC44 - which are four "strings" which go inside the unit. Assuming it is just the (2) RBC44 - four strings/modules internal to the UPS, sometimes it can just be one or two strings that have a problem or all of them. The first thing we'd ask in this situation is to verify the environment that this UPS is in to see if this has somehow contributed to a premature battery failure. Otherwise, I don't think there will be much to do to really narrow down the string(s) and doing in depth testing to see if there is just a bad 12V battery inside the 96V string. This is not something we typically have users do but some advanced users choose to do it.

Depending on what you found in the environment or at the battery string level, and if these were genuine APC RBC44's, technical support could replace one or both of them under warranty since APC batteries have a (1) year warranty on themselves.

[Anonymous user · Accepted solution]

Speaking from hands on experience it can sometimes be challenging to determine which battery modules are bad with these RT UPS. An RBC44 ( two skinny modules) counts as one string because the two modules ( nominally 96 volts per Angela N's post) are in series with each other - IE connected end to end like Christmas lights. Inside the RT10000 UPS itself there two 192 volt strings in parallel with each other. In the external battery modules (also having two RBC44's / 4 skinny modules) it is the same. Having access and knowing how to use a DVM (digital multimeter) is almost essential, as you can use it to measure the voltage at the black battery connectors for each module (either when plugged in to the UPS, or unplugged).

If you have a multimeter and know how to use it, with the battery modules plugged into the UPS, measure the DC terminal voltage between pairs of adjacent batteries. If the batteries are relatively healthy you should measure about 108 to 109 Volts DC at each module...differences of a half to one volt or so are ok. If one or the other module has one or two cells going bad inside, you will see an imbalance Eg you might see 111 to 113 or 114 volts across one, and 103 to 105 or 106 volts across the other. After that the next step is to disconnect the cells and measure the voltage at the battery connector (while loose) and see what it is. On a healthy fully charged module the voltage should be around 103 to 104 volts DC. The module with the lower voltage usually is the one going bad, but sometimes its the opposite, as dying cells inside the module can sometimes be overcharged by the UPS and show a higher than normal voltage.