[SOLVED] APC-Back UPS-RS 500 continuously clicking

Hi,this is Nathaniyelu from INDIA, i got a problem with my APC Back-ups-RS 500,purchased in 2009,
relays are continuously clicking ..later i opened and found Two Electrolytic Caps bulged(each 4.7MF,450V) and one Cap(blackened--22MF,50V) i replaced all with new ones and connected to supply(220V 50Hz),now the UPS continuously beeping whenever switch ON,few days back i connected LCD monitor to UPS without mains..i.e on Battery ,LCD monitor was not ON but relays r continuously clicking...earlier Battery Charge without load..12.48V..now 9.3V. without battery there is 3V across battery charging terminals ..what could be the problem...,
Thanks in advance...

Most chances are,battery charging section is not working,
At a glance i observe that ups is built in smps charger.
This page may be helpful, **broken link removed**

have you check the connection near the caps? check also the contact of 2 power resistor sometimes it will get cold solder, just check it..., if you think everything is good and still the problem occur you can check also the MOSFET.

Hi poweraces,This Tuesday(3June2014) what i did, i had connected a Battery eliminator in place of UPS Battery and switched ON UPS .Now UPS was On as like Battery mode ,gave single beep for every 5 seconds !!,now I connected UPS to mains ,it turned ON Normally!!!! at this time i switched off UPS and checked (disconnected eliminator) voltage across Battery charging terminals..it was 13V..now i connected battery and left for one day to charge .(Charged from 8.8 to 10.5V).Now i switched ON UPS ..first it gave continuous beeps later it was ON,this time i again OFF the UPS switched ON ..now once again relays were continuously clicking...I repeated above procedure and put the UPS in charging for 3 days(As mentioned in Manual for complete charge)..and i will see if the Battery can be recharged..
What is the minimum voltage level of an UPS battery to ON..??
What will be the Full charge ..??
Thanks in advance.

If the voltage across the terminal (black and red) is 13.58Vdc that would be normal that is the float charge for the UPS and also 13V something is the full charge for the battery.

UPS will power on ( Cold Start ) if the battery voltage is 11Vdc up...,

If the relay keeps on clicking most likely the problem is Caps, transistor (PNP & NPN) also IC (im not sure if that model came with LE50 or LP5050 IC its a 3 pins component),

Hi Poweraces..,yesterday(6june2014)..i had found that the UPS Battery not recharging..and noticed it became bulged!!!(may be at the edge of Explode!!!) some chirping sound also coming.at this time i switched on UPS on mains there was continuous Beeping!!!.now i disconnected from UPS..and checked its voltage 9.2V..not raising anymore..seems need a New Battery.. you are not suspecting UPS Battery already its 5 years Old..!!??

Is the battery a gel cell type? We had a back-up UPS with gel cells. They started losing capacity after 3 years, and needed to be replaced.

A gel cell cannot tolerate too great a charge. Bubbles of gas develop on the lead plates. As I heard it, these bubbles do not disappear. They remain on the plates. This reduces the battery's power output, and shortens its useful life.

It is too soon for you to install a new battery. Right now you ought to check how much current is going into the present battery. It sounds as though it is ruined. Or in any case after 5 years we would expect it is used up.

Do you have an old 12V automobile battery? That would be more suitable for testing your UPS.

Hi BradthRad,
i dont know which type it is..the battery is made in China..CSB--UPS 240 model..
specificationswww.csb-battery.com)
Standby use:13.5~13.8V
Cycle use: 14.4~15.0V
Initial current: 2A Max..

i don't have 12V automobile battery..

I see that battery in the picture, it indeed seems like a gel type.
And by the way, you had asked about the thresh-hold voltage required for an inverter to work... Well it is about 10.5V ( as far as I can recapitulate from a few manuals)

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Relays my be clicking because....
Under no load, the battery voltage may be rising just above the thresh-hold, but as soon as the battery is connected, even a small amount of current ( perhaps even the magnetization current required by the transformer) may be pulling down the voltage level below the thresh-hold. Thus activating the relay, and as soon the battery is disconnected the terminal voltage will rise again.... and the cycle continues.... This happens if the battery is no more in usable state. Although the no-load terminal voltage may be ok, the internal resistance may have risen beyond acceptable limits.

Nathaniyelu said:

Hi Poweraces..,yesterday(6june2014)..i had found that the UPS Battery not recharging..and noticed it became bulged!!!(may be at the edge of Explode!!!) some chirping sound also coming.at this time i switched on UPS on mains there was continuous Beeping!!!.now i disconnected from UPS..and checked its voltage 9.2V..not raising anymore..seems need a New Battery.. you are not suspecting UPS Battery already its 5 years Old..!!??

Click to expand...

the 9.2V is from battery or from UPS charging terminal? if the 9.2Vdc is battery you need to replace the battery. UPS battery usually use AGM type of battery. if the 9.2Vdc from the UPS terminal now your have a problem your charging ckt you need to fix that.

9.2V from Battery..across UPS charging terminals...13.51V coming...yes i would like to purchase New Battery..which Battery is best??i.e company and Ah rating..

Hi all, i had purchased a new Battery( made by APC only Matching) and fixed ..Now My UPS is working Properly ..Thank u very much for your kind Help..i would like to Thank Edaboard forum...Thanks a lot...

good job..., please mark this thread as Solved.