SUART8000XLT not charging batteries

[Anonymous user]

I have four SUART8000XLT systems, each with the big external step-down transformer and one external battery pack each installed into my server room. Over the holiday weekend, the building's circuit breaker for one of the 4 systems failed, losing only one of the two legs of the 208v AC circuit feeding the one UPS. The batteries ran down all the way down and it of course shut off. We've had the circuit breaker repaired, and the UPS powered back up, but only the bottom most battery LED lit up and it was blinking. I swapped out all the batteries with a second SUART8000XLT system, and it charged them all back up to 100% just fine, but the fully charged batteries from the 2nd system that were placed into the first system slowly discharged and they're not getting charged back up at all. I tried a manual "recalibration" routine I found instructions for a different model, but it did no good. The system in question passes its self-test and reports no problems.

Is it possible that the charging circuit in this UPS is just simply failed even though the self-test says nothing wrong?

I've got about 4 months of standard warranty left, and so will call APC tomorrow to see what they say.

[Anonymous user]

I just tried another "manual recalibration" procedure to see if that would help, but it did not.

Right now with the batteries in a mostly discharged state (after the latest manual recalibration "rundown"), and the unit freshly plugged back in and started up, the voltage is showing 197.6VDC which is giving a 22% level. Sometimes when I power the unit up, one or two battery LEDs on the bottom will light up blinking, but sometimes they come on solid.

When I put freshly charged, known-good batteries in it, power it up and login to the web GUI, the voltage is briefly 216.0VDC and 99% at first for just a very short while then both the voltage and percentages start dropping downward and never return.

This same set of batteries stays at 216-217VDC and 100% when I place them into any of my other three properly functioning UPS systems. I've now swapped batteries three times amongst the systems and this demonstrates that the batteries themselves are all still good.

[BillP]

Hi,

Your battery have some block failure inside battery module. The UPS detect enough VDC for whole battery module not each block. It's will say ok if this VDC reached the setpoint.

1. When your single block failure, it's can asbord charged current.

Example you have 2 block 12V 6 cell VRLA in serial connection. Typical you need good voltage is 2*13.75 = 27.5V (or let say 28V)
When discharged on 1.7Vpc, lowest voltage is 2*6*1.7= 20.4V.

==> If it's failure 1 block : when recharged one block can give up to 18VDC, and the other may be only 10VDC (Still weak). But whole module is 28VDC, and UPS still say it's ok.
When apply the load, the run time will drop very fast since this module is not full charged yet.

In long time, your good battery become overcharged and damage also.

2. Solve :

Some tactics: you need measure Voltagge in block to detect weak battery block. Take out these weak blook and charged in separate charger. In serial connect charged it's wont help.

Tried to discharged it 1 - 2 time and charged again

Put all the block in to the battery module and discharged 1 time. Recharged again as final.

Message was edited by: trinhkhai79

[Anonymous user]

APC tech support says an internal failure.

Surprisingly enough, they say the self-test does not test the charging circuit in this system.

Looks like I'm going to have to process a warranty replacement for this unit.

[BillP · Accepted solution]

do you have a voltmeter to check the voltage on them and let us know what they read for DC voltage? that'd be the first thing I ask and the first thing i assume tech support would ask. if you install them back in the UPS, it should also read the voltage for you too i think.