Replaced batteries in Smart-UPS RT 1500 XL and Smart-UPS 3000 RM DL3, same poor battery run time

[datajerk_apc]

This was originally posted on APC forums on 6/21/2018

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Hi,

I have (circa 2005) Smart-UPS RT 1500 XL and (circa 2004) Smart-UPS 3000 RM DL3 UPSes in my lab.  About 6 months ago I replaced the batteries, but never got around to the recalibration.  I assumed the estimated battery run time reported for both units was erroneous and would self correct over time.

Nope.

So I attempted to recalibrate the 3000 RM today.  I tried the serial cable method (proper cable, 2400 8N1, send a "Y" and wait for a "SM").  That didn't work (never got back an "SM").  I know the cable is good because I tested with apcupsd before I racked the units.  In both UPSes I am using the RJ USB connector, perhaps if that is connected or used the serial port will not respond.  I disconnected and tried again with serial.  Nothing still.  Perhaps the UPS is locked in to using the RJ port until power cycles?

Anyway, moving on...

I tried the put at >30% load (used 37% load) and drain to 25% method, but that didn't work either.  The UPS drained very quickly.  As if the estimated runtime was more accurate than the battery load.  I should have connected a meter to the batteries.  apcupsd reports 52.4 and 54.3 volts.

I have two new (6 month old) Back-UPS RS 1500Gs, one with the extra battery pack.  If I connect the same load to it, it reports about 10x more battery run time.

What else should I try?

[datajerk_apc · Accepted solution]

This was originally posted on APC forums on 6/21/2018

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Update, using apctest I was able to do the proper calibration.  I watched the battery percent drop from 100% to 25% in 500 seconds with a 37% load on the 3000 RM.  That does not seem right.