APC UPS charging problem

[theone]

Hi,

I have an BR550GI Back-UPS pro APC UPS for a few years.
Recently I replaced the battery (not the first time) and am having strange issues with the UPS.
I charged the battery for several hours to make sure it is full.

 

The issues I am seeing (UPS is connected to PC with PowerChute SW for diagnostics):

• When connecting to a load (lamp/Computer - tried both) and UPS is connected to AC mains the capacity % goes down in jumps of ~7% over hours (not one percent at a time).
• When disconnecting the load and UPS is still connected to AC mains the UPS does not charge the battery. % keeps dropping same as previously.

What can be the problem?

Notes:

• When powering off the UPS and UPS is connected to AC mains the UPS does charge the battery (% goes up slowly until it reaches 100%)
•  opened the unit and saw no swelling in capacitors

 

 

[Vr2Io]

Problem likely hardware fault that UPS always in battery mode ( or in battery capacity calibrate ? ), you should use amp clamp meter to check battery in charging or discharging.

 

Suggest power-off UPS from AC mains and disconnect battery and try again.

Edited March 6, 2022 by Vr2Io

[theone]

1 hour ago, Vr2Io said:

Problem likely hardware fault that UPS always in battery mode ( or in battery capacity calibrate ? ), you should use amp clamp meter to check battery in charging or discharging.

 

Suggest power-off UPS from AC mains and disconnect battery and try again.

Amp clamp meter on battery leads?

 

I disconnected mains and battery more than once, also did logic reset procedure (press power on a few seconds when all is disconnected) and it did not help.

 

UPS does not seem to be stuck in battery mode because when I do self test I can here the clicking of the relays from mains to battery and back.

 

[Vr2Io]

13 minutes ago, theone said:

Amp clamp meter on battery leads?

 

Yes, Battery RED (+) or Black (-) wire, you may got 9+ amp reading even no AC load during discharging.

 

13 minutes ago, theone said:

UPS does not seem to be stuck in battery mode because when I do self test I can here the clicking of the relays from mains to battery and back.

Yes, this indicate switch between mains and UPS work..

So it still look like UPS inverter function ( DC to AC ) always wrongly activate, otherwise no reason with AC mains, battery level will drop and ~7% over hrs.

Edited March 6, 2022 by Vr2Io

[theone]

3 minutes ago, Vr2Io said:

So it still look like UPS inverter function ( DC to AC ) always wrongly activate, otherwise no reason with AC mains, battery level will drop and ~7% over hrs.

 

Even if it was wrongly activated, and there is no load, why would the battery drain? where to?

 

[Vr2Io]

Just now, theone said:

 

Even if it was wrongly activated, and there is no load, why would the battery drain? where to?

 

Dissipate in switching circuit and transformer, if no load may be 2 ~ 4 Amp, should not high as 9+ Amp.

[theone]

OK, so I did some measurements and here they are (battery at >95% when started test):

 

No load:

1. Mains disconnected and UPS off - PowerChute "Disconnected" 0.00A 12.76v
2. Mains connected and UPS off - PowerChute "Charging" Negative 0.02-0.04A 12.89v
3. Mains connected and UPS on - PowerChute "Charging" 0.09-0.12A 12.77v - battery % is decreasing slowly
4. Mains disconnected and UPS on - PowerChute "Discharging" 0.45A-0.60A 12.49v - battery % dropped almost immediately by 10%
   Connected mains back resutls are same as in (3) above.
   Repeated and same thing happened (including the % drop - 7% this time)

 

With 60W (lamp) load:

1. Mains disconnected and UPS off - PowerChute "Disconnected" 0.07A-0.05A 12.72v
2. Mains connected and UPS off - PowerChute "Charging" Negative 0.02-0.04A 12.81v
3. Mains connected and UPS on - PowerChute "Charging" 0.09-0.12A 12.68v - during the power on I get 4.8A
4. Mains disconnected and UPS on - PowerChute "Discharging" 4.82A-5.25A 11.98v - battery slowly decreases
   Connected mains back resutls are same as in (3) above.
   Turned UPS OFF and ON again and am seeing 0.15A-0.17A.

I think the only time I get charging (Negative current) is "With Load" and "Mains connected and UPS off"

But that is VERY low charging current...

 

In both (3) although PowerChute says charging I have a positive current meaning discharging.

 

So it seems that my UPS is only charging when OFF and at a VERY slow rate.

 

What could be the problem?

 

Edited March 6, 2022 by theone

[Vr2Io]

1 hour ago, theone said:

Mains disconnected and UPS on - PowerChute "Discharging" 0.45A-0.60A 12.49v - battery % dropped almost immediately by 10%

If no load during discharge, my measurements ( from my memory ) won't such that low. I notice you use 60A bar to take measurement it could make larage difference result.

 

BTW, review the problem again, it may be battery not fully charge or battery in fault, so even with small load, voltage will drop abnormal quickly, if you have standalone charger then you can try fully charge it, then make same discharge test to verify relate UPS charging prolem or not.

 

1 hour ago, theone said:

But that is VERY low charging current...

Agree, Such low charging current will happen on fully charge state, but battery never higher then 13v so not in fully charge actually.

 

 

Edited March 6, 2022 by Vr2Io

[JonathanM]

Have you set a new battery date in the UPS firmware?

[theone]

6 hours ago, JonathanM said:

Have you set a new battery date in the UPS firmware?

Yes

 

[theone]

I drained the battery completely and used a borrowed battery charger (SON-1206D) to charge the battery.

It reached 13.6v after full charge (took slightly more than 1 hour @ 6A).

 

I then connected to UPS and again fully discharged the battery and then started to charge via UPS.

Charging current is still very low ~0.2A.

 

Edit:

Looking again, carefully his timm, at the UPS specificationns I saw

https://www.se.com/il/en/product/BR550GI/apc-powersaving-backups-pro-550/

 

So maybe the 0.2A (sometimes went up to 0.3-0.35A) could be OK assuming charging voltage is ~14.0-14.5V (5W/14.5V = 0.35A)

 

Edited March 7, 2022 by theone

[theone]

So I charged the battery with the battery charger.

Placed in the UPS

Updated date

Connected to Mains with no load and UPS on

And waited...

 

After 4 days the battery decreased to 46%. 7% every 12 hours (in jumps of 7% - not 1% at a time)

 

To make sure it was not just a report error by the UPS or PowerChute SW I connectred it again to the battery charger and indeed the battery was drained down to ~50%.

 

So I have a faulty UPS - leaking battery power to somewhere... and UPS not charging the battery when it is ON.

 

I will probably have to buy a new UPS 🙁

 

Edited March 10, 2022 by theone

[Vr2Io]

51 minutes ago, theone said:

I will probably have to buy a new UPS 🙁

Yes

[theone]

After following the help provided here I was able to get the UPS working again. YEY !!!

 

Now I get good numbers:

1. Mains disconnected and UPS off - PowerChute "Disconnected" 0.009A 12.72v
2. Mains connected and UPS off - PowerChute "Charging" Negative 0.7A 12v+ and rising
3. Mains connected and UPS on - PowerChute "Charging" Negative 0.55A 12v+ and rising - no decrease in % over time as before 🙂
4. Mains disconnected and UPS on - PowerChute "Discharging" -6.6A 11.98v (60W lamp) - battery slowly discharges as expected
5. Connected mains back resutls are same as in (3) above.

 

[S80_UK]

Well done!  So, you had some tired capacitors?  It does happen, and probably more frequently with budget models.  Capacitors age from time, current and especially from operating at elevated temperature.

[theone]

I wouldn't have thought that a change of 10% in capacitance (330uF --> 300uF) would have such an impact on the UPS operation.

But it seems it does...😕