Smart UPS 10KVA extended outage, new batteries, blew mains fuse.

[BillP]

Hi All,

I am in the process of diagnosing why our 2 year old 10,000VA UPS has been powered off since before I started in post as Network Manager 10 months ago.  The unit has been offline but connected to the mains for over 12 months to my knowledge.  The unit would not power on at all and we suspected the batteries were at fault.  We have just installed the new batteries today and attempted to power the unit up.  It did not have any load connected at the time. The chain of events were as follows:

1. Isolate unit from mains.

2. Install new batteries.

3. Power on unit with the test button.

4. Unit begins to power on, relays click, lights start flashing on the front etc...

5. Turn back on mains power.

6. Approx 1 min after applying mains power, large bang and flash from the from of the unit.  No burning smell or smoke etc...

7. Unit is still powered on at this point but as a precausion we quickly hit the mains isolated switch on the wall and powered the unit of using the buttons on the front.

8. The 63A fuse on the main distribution board had tripped.

We have not returned mains power or tried to power the unit back on since the event.  I have had a qualified electricion confirm the unit is wired to the mains correctly and that the curcuit is ok.  All battery connecions were securly in place.

Any suggestions on what our next course of action should be?  Is it safe to try powering the unit back on?  Should I of applied mains power first before powering it on from extended outage?  Could one of the new batteries be faulty as the flash/bang seemed to come from near the front of the unit around where the batteries plug in?

Unit is 6 months out of warranty, go figure.

[BillP]

Hi Dan,

This loud bang and tripping of the upstream breaker after trying to start the unit after a 12 month hiatus leads me to believe that a capacitor within the unit sustained damage.  Did you notice any faults given by the unit between the time of the noise and powering down the unit?  I cannot safely recommend using the unit anymore should it truly be an internal issue with the capacitor. 

Regards,

[BillP]

We managed to get the error lights from the front.  The fault light was lit and the battery fault code was 0 1 1 0 0 0

[BillP · Accepted solution]

Daniel,

If the top led is the first digit  and the bottom led is the last digit all the way to the right in the code you shared, then the unit has experienced a battery capacitor soft start fault which would confirm an issue with a capacitor.

Sometimes bad batteries can cause this, however if you heard a loud pop and flash along and the batteries you installed are new, it is safe to say it is a unit fault.

Regards,

[BillP]

Yes that is correct with the LED order.  

Being out of warranty and a very crucial unit we will go ahead and replace it with a new one asap.

Thanks for your help troubleshooting this.

[BillP]

You are welcome Daniel.

Take Care,