APC BR550GI Pro UPS not charging battery

[theone111]

I have an APC BR550GI Pro UPS
https://www.se.com/il/en/product/BR5...ckups-pro-550/

The motherboard model I have in the UPS is the 640-1172A-Z_REV05

The problem I have is that my UPS does not seem to charge the battery when ON.
After charging the battery with an external battery charger and installing into the UPS (updating change date) the battery drains slowly ~7% every 12 hours with no load connected (the PowerChute SW show decrease in jumps of ~7% not 1% decrements).

I think it does charge the battery when OFF because I measure ~0.3-0.4A on the wires to the battery. and when connecting external battery charger it does say battery is at 100%.

The UPS does switch from Mains to battery and back when it should.

I see no physical damage to the board.

The 2 fuses F4 and F5 are OK.

Does anyone have the schematics of this board or can help point me in the right direction for troubleshooting and finding the bad component/connection.

Thank you

[sam_sam_sam]

What is going on with the device that is on the heat sink it is looking odd it near T1 and I think is also near IC2 can you please post the part number for IC2

[theone111]

Originally Posted by sam_sam_sam

What is going on with the device that is on the heat sink it is looking odd it near T1 and I think is also near IC2 can you please post the part number for IC2

IC2 is TNY278PN (I am waiting for order for replacement - maybe it will help)

What device looks odd? The silver one I marked PINK In attached picture? I don't know what it is? Why do you think it odd?

[sam_sam_sam]

Is there an ic chip that is mounted to it or something else that is mounted to it

[theone111]

Originally Posted by sam_sam_sam

Is there an ic chip that is mounted to it or something else that is mounted to it

I have no idea what it is. There are no markings.

[benq32]

Originally Posted by theone111

I have no idea what it is. There are no markings.

This is simply heatsink for TNY278PN.

I have the same symptoms. I've changed TNY278PN chip, but there is no changes. Problem exists.
battery will not charge!
If I switch UPS on, it makes it internal tests, shows that battery is empty, but no error message.
If I disconnect the battery and measure voltage on battery pins, it's about 9V -- this is the reason why the battery does not charge.

Has anyone Idea why it could happen? Why it does not charge the battery?

Best regards,
Q

[benq32]

There are two capacitors on th board -- C18 and C32

Please take a look at the capacitor C18. It is 330mkf
I've measured it with multimeter and it was about 250mkf...
I've changed it to something I've found (470mkf 50v) and UPS is working again. Charge voltage about 13v!
Hope this helps you.

Solution - change capacitor C18.

Best regards,
Q

[theone111]

Originally Posted by benq32

There are two capacitors on th board -- C18 and C32

Please take a look at the capacitor C18. It is 330mkf
I've measured it with multimeter and it was about 250mkf...
I've changed it to something I've found (470mkf 50v) and UPS is working again. Charge voltage about 13v!
Hope this helps you.

Solution - change capacitor C18.

Best regards,
Q

Did you measure them (C18, C32) out of the board (removed from board)?

I meausred them on the board (they seem to be connected in parallel and got ~600uF (they are each marked as 330uF 35v). I will try and remove them and measure outside the board.

When I power up the UPS with no battery connected I get ~5.4v and a buzzing sound (see attached zipped video)

[benq32]

Yes, I've measured them by removing from board. If I measured them on the board, it was more or less normal, but it was not so.
I've orderen another elkos 330mkf 63v from Panasonic.
now all is working fine!
Change your capacitors and have a look what happens.

[stigger]

I had exactly the same problem. My capacitors looked fine, but tried to replace them with 330uf 35V Panasonic and that helped. Thanks a lot for the tip!

[theone111]

So I replaced c18 and c32 (i measured them after removal and they were about 300uf instead of 330uf).

Now I get 14.1v when no battery connected and get charging current (measured on the battery wires) of about 0.5A and battery voltage increasing slowly.

Is this charging current OK?

[theone111]

Originally Posted by benq32

Yes, I've measured them by removing from board. If I measured them on the board, it was more or less normal, but it was not so.
I've orderen another elkos 330mkf 63v from Panasonic.
now all is working fine!
Change your capacitors and have a look what happens.

So I have tested the UPS after the capacitors replacement and it seems to work.

Thank you @benq32

[lego1234567]

Originally Posted by benq32

There are two capacitors on th board -- C18 and C32

Please take a look at the capacitor C18. It is 330mkf
I've measured it with multimeter and it was about 250mkf...
I've changed it to something I've found (470mkf 50v) and UPS is working again. Charge voltage about 13v!
Hope this helps you.

Solution - change capacitor C18.

Best regards,
Q

I had the same problem as you, battery was not charging at all. After removing and measuring the C18 and C32, I found they had much lower capacity (not any visual damage). After soldering new ones, UPS works fine. Thanks for your efforts !

[sam_sam_sam]

More items not ending up in a landfill good work to both of you