Hi!

I have a Back-UPS Pro 550. After replacing the battery, I realised that my unit was not charging the battery anymore when powered ON. Tests I have conducted so far:

1. If the unit is powered ON, the battery does not charge
2. When powered ON and I disconnect the battery I can measure 13.78V on the battery poles, so Voltage is there from the DC converter
3. When I shut down the UPS, then the battery starts charging: I see the voltage slowly increasing and after 2 days the battery was 100% charged

Based on the above it seems to indicate that charging circuit is OK, but it might be a SW issue or some failing sensor that cuts battery charging ? Is there any reset function or FW update that I could apply ? Anything else I could check / do to fix it ?

The unit is around 5 years old so not covered by warranty but still not that old :-)

Thanks

Hi,

You can try and brain dead the UPS to reset it.

See Schneider Electric FAQ FA158947 for instruction. 

the basic troubleshooting steps for the APC Back-UPS Pro with ... The Back-UPS is not connected to AC power, there is no AC power ... The battery will not charge if the temperature is over 50 degrees Celsius 

On 11/19/2020 12:19 PM, Bill said:

You can try and brain dead the UPS to reset it.

Hi, thanks for the replies. I did try a brain dead reset + another type of reset I find on the internet, no success.

After opening the device I located a bad capacitor (see picture).

After replacing it, the charging process of the Battery is working again!

Thanks for the quick answers and the help.

I have the same problem with this model.

APC wont do anything. It seems to be a problem with this model.

I will give a try to search for the capacitor. Thx for the input.