SURT10KRMXL + 2 x SURT192XLBP => Problems

[BillP]

As per the title, I have an SURT10KRMXL + 2 x SURT192XLBP - which I inherited from another department, complete with their settings.

The batteries had reached their end-of-life, so over the weekend I replaced all of them with brand new ones, and reset the "Last Battery Replacement" date.

Previously, there was not enough power to even sustain a self-test, but now it passes a self-test just fine.

However, the remaining run-time with a 35% load is showing as only 30mins, and every 4-5 hours (I haven't got an exact timing) I get a persistent beeping for about a minute, which I believe is the "replace batteries" warning.

The Battery Voltage is showing as 217 VDC which seems a bit high to me, as if it's constantly on charge? but I readily admit that don't know what I'm talking about.

Basically, what do I need to do in order for the run-time to make sense, and for it to stop thinking it needs new batteries ?

[BillP]

I've done a bit of sleuthing on this myself, and so far don't have a clear solution.

From what I've gleaned, when the batteries have been completely depleted (as were the ones in this configuration) the mircoprocessor needs to be reset, and that a calibration using the NMC interface won't do the trick.

The recommendation is to perform a manual calibration using a non-critical static load of at least 30% capacity, by pulling the input and running it to shut-off ??

Well, I sure don't have a non-critical static load of 30% 10KVA capacity I can put onto this, or the available down-time to run 6 x RBC44 packs flat.

I've read some basics about an alternative approach to reset the runtime, by using the serial cable and a "PROG" mode.

However, I don't have the correct value to enter, for my combination of UPS and external battery-packs.

Would anyone know the correct value, and have any definitive guide to follow for using PROG mode ?

BTW: I did some quick calcs on the 217 VDC value displayed for the battery voltage, and am assuming this is the average float voltage of the RBC44 battery pairs?  If so, and using 16 batteries per set, that would be an average of 13.56 VDC per battery... which I guess is about where a float voltage should be.

[MarkC_apc]

I've had (apparent) success in recalibration on SU and SUA3000's by simply applying a load around 30% VA until the low battery alarms, then re-applying the mains.   Exercising the new batteries is not a real problem for them at such a load as the SOC is above 30-40% at the end of such "tests" anyway (from the voltage "rebound" after the test with no load, before I re-apply the mains).   A side advantage is that you can compare the "test" against the curves for new batteries (make sure the number of packs is properly configured).  If you suspect that the new batteries may be under-performing, you can monitor the voltages of each battery cage (be careful with the probe!) to ensure they are all about the same at any point along the test (should be 1/2 the total).  If one is out of balance, there could be a bad battery (even though new) in that particular cage assembly which would bring down the entire run time.  Keep in mind that the run time will be slightly shorter than the curve simply due to not running to shutdown - but from my experience, not much different.

It appears from your normal load this can be done effectively by simply disconnecting the mains - at least you'll be there monitoring closely if something goes wrong. 

IMO, using PROG has it's own risks - maybe greater than a "calibration" test.

BTW, the float voltage of 13.5+/- is about right.

[BillP]

Thanks for that.

I'll give it a try this weekend, although I have to say that I've not had much luck with this approach in the past.

I'm assuming that I'll need to disable the PNS service on the servers, to stop them automatically shutting down when the low-battery warning is reached.

[BillP · Accepted solution]

DOH!!! - found the cause of the "replace batteries" beeping.

At the bottom of the rack next to the one holding the SURT10KRMXL + 2 x SURT192XLBP, there is an SU1500RM that has been doing nothing for a few years.

The "replace batteries" beeping was "obviously" coming from the SURT10KRMXL, because we'd totally forgotten that we even had this other UPS.

Finally, when it started beeping today, I charged into the server room and saw a flashing light where I wasn't expecting to see one, and... OH, OF COURSE!!!

Time to pull it out, swap out some batteries, and put it on Ebay.