Charger voltage are too low

[Anonymous user]

Hi

I am facing charging issue in BX650CI UPS. The charger voltage are too low i.e.8.3VDC. According to my understanding it should be near about 14VDC.

I have swap the battery with new one but issue not resolved.Kindly look into it. Snap attached.

Mukhtar Ahmad

[Anonymous user]

Hi

I am facing charging issue in BX650CI UPS. The charger voltage are too low i.e.8.3VDC. According to my understanding it should be near about 14VDC.

I have swap the battery with new one but issue not resolved.Kindly look into it. Snap attached.

Mukhtar Ahmad

[Anonymous user · Accepted solution]

Yes, if the UPS was healthy you should definitely be measuring at least 13.5 to 14 volts at those spade terminals. Are you feeding the UPS the correct input voltage (and frequency) ? (looks like 230 volts AC ?). With the battery plugged in do any fault indicators light up as you power up the UPS and it does its self test ?

[Anonymous user · Accepted solution]

Thanks for reply.

Yes. 228VAC and 49.98Hz. When charged battery plugged it is working fine but when take some backup battery low and not charged for next.

[Anonymous user]

Unfortunately from what you report it sounds like the UPS has an internal fault. This fault may even be going undetected by the UPS self-testing process when you have a fresh battery connected ?

[wayne_i_apc · Accepted solution]

As a better test, I would measure the output voltage of the charger with it connected to the battery, NOT with the leads disconnected, as you show in the photo. Allow sufficient time for the battery to charge / recharge. From a deep discharge it may take several hours to reach 13.5 volts or more, I don't know what this UPS specifies for recharge time. If after running the UPS on battery for several minutes with a modest load (say 10 minutes with 100 watts) the battery returns to more than 12.5 volts after restoring AC power I would say your charger is operating, and your 8.3 volt reading is invalid. Again, it will take time to recover to the maximum voltage, close to 14 volts, and even then more time to charge to full capacity.

[Anonymous user]

I've worked with almost the entire line of APC ups and cannot recall one amongst these smaller line interactive models that doesn't present full charging voltage to the battery terminals with no battery connected......but perhaps someone from APC could clarify/confirm for this particular model.  The recharge time on this model is stated as 8 hours.

[Anonymous user]

One other thing to check would be that the UPS's rear panel "Battery Connector"  (...its at the upper right hand corner of the back panel ) to make sure its terminals are in good condition and not weak/loose.

[wayne_i_apc]

Battman, I'll defer to your experience here... I was thinking of a more general case where a voltmeter will incorrectly read the average of short pulses from a more sophisticated charger. Also, there could be conditions where you could read the "proper" voltage at the disconnected terminals but still not be able to charge a battery when connected. I thought Muahmad may have overlooked (or not reported on) some diagnostic steps.

[Anonymous user]

I have check the rear fuse it is OK. I would also come to you knowledge that I have one same model UPS. It is showing correct charger voltage i.e. 13.89VDC. I have also check my voltmeter it is also showing proper voltage.

[Anonymous user]

Your only option now is either to replace the UPS or have it repaired.... if you are skilled / careful with electronics you could unplug the UPS and let it sit for a couple of days to discharge the internal components then remove the cover and check for damaged components. If you have some component damaged in the charging circuits that may reduce the voltage and not provide any charging. There might be a blown MOSFET, or possibly a failed filter capacitor in the Charging section that is dragging down or weakening the charging voltage.

Good luck !

[Anonymous user]

Thank you so much Battman.

Tried my best to repair it. Do you have some internal diagrams. Please share if you have. 

[Anonymous user]

APC does not officially release Schematic diagrams but as is the norm on the internet some things are available if you google search for it... I have not personally come across a schematic for that particular model but you may find very similar ones architecturally in that size range that could be helpful as a guide. Very difficult to do board level repairs on ups usually a lot of damage (sometimes hidden) occurs if components blow. Good luck to you!