Symm LX batteries flagged bad prematurely during back-to-back outages. Ack!

[Anonymous user]

I have a pair of Symmetra LX Towers that are only 2 years old, sitting in a nice cool room. On saturday we had two successive unplanned power outages (3 hours apart) that both times completely drained the batteries (20 mins runtime on two SYBT5's per unit). According to the event log, right a the end of the second outage - fourteen seconds after the UPS turned off due to low battery - the ups's reported "UPS Battery Failure" and then one second later "Batteries require immediate replacement".

On the suspicion that maybe a few of the jars had gone bad in each module, I tore apart one of the SYBT5's, only to find that the voltages and internal resistances on all ten jars were fine. I did the same with a pack from the other LX, with same results...all jars were around 13.7 volts, no more than 100 milliohms resistance...most were at 85 milliohms. I have brand new Panny 12V 7.2 Ah cells that measure more than that. Yet, the UPS diagnostics menu is reporting "Weak Battery" for each and every SYBT5 module.

This brings up several big questions:

Firstly I am confused as to the timing of the battery fault, why would a pack be flagged as bad at the end of an on-battery operation, at a time when the batteries are totally drained and the UPS has no power ?

Why wouldn't the UPS firmware wait til power was restored, recharge the packs to full capacity and at the end or during that process determine if any modules are bad ?

Could this be an issue of the batteries not actually being fully re-charged after the first outage (even though the UPS data logs reported they were at 100% when the second outage hit, there was only three hours charging time), so the discharge was far more rapid the second outage (which is supported by the data logs) and the LX's processor falsely thought the packs were weak ?

Why are the packs being flagged as bad when my measurements show they are good ?!
( I have a B&K 601 tester ).

Also, I see the SYBT5 has an internal circuit board like Smartcells do. Is this board responsible for monitoring the health of the jars, and can it be reset like the smartcell board can ?

Cheers,
...Dave

[BillP]

Battman -

i ran into a similar problem but was told that the batteries were not resettable at that time (possibly about a year ago). Did you call the TS line to see if they had any suggestions for resetting? (possibly pulling the batteries out and re-installing them one by one) the batteries sound like they are good to go, same measurements I would expect to see. What are the date codes on the batteries? they dont sound like weak jars so maybe its related to that chip inside....

[Anonymous user · Accepted solution]

Thanks for your answer, I put in a case with tech support and have recieved a brand new set of SYBT5's already (under warranty). I will still look around to see how to reset the SYBT5...this was not a case of infant mortality - I am guessing the firmware on the UPS (MIM OS) is too strict with monitoring discharge curves of the cells. Yes, I tried disconnecting the string internal to the SYBT5 but nothing was reset.

Dave