ES 550 shuts down suddenly when printing a document

[Anonymous user]

after working flawlessly for past 3 years, my UPS ES 550 decided to shut down suddenly today while printing a document. Worse still, is that the battery backup doesn't kick in to keep the computer running, everything goes dead together, instantly.  After I shut off and push the reset button on the UPS and then turn the computer back on, everything works fine until the next time I try to print again.  Also, would point out that until the shutdown occurs, the green light appears normally, and i have never seen any red blinking light or warning alarms to suggest the battery or unit is otherwise defective.

Before anyone says "don't plug a printer into the UPC!", I will state that the only thing plugged into the unit is the desktop computer (with standard 250 watt power supply) and my computer monitor.  The printer is plugged into a separate power outlet.

I have reproduced the situation several times, and the fault continues.  I tried switching out the ups for another unit and the problem is not occurring now... so it would appear there is something wrong with the ES 550.

Any ideas would be appreciated!

[Anonymous user]

When you mention a "reset" button, are you referring to the power switch or circuit breaker on the unit? If the UPS's circuit breaker has tripped, the problem is likely internal to the UPS.

I believe the battery within your Back-UPS ES 550 is extremely weak or bad, regardless of whether it has produced a failure alarm or not. Practical experience suggests these units are not particularly good at noticing when their batteries have failed. Even if they do, the failure state is not retained if the unit is restarted. Some older models also lack the red LED.

The printer, which I'm assuming to be a laser type, may be able to trigger enough of a voltage sag that the UPS circuitry tries to intervene and falls over due to  flat battery. This could be true even though the printer is plugged in to a different outlet, if that outlet is on the same circuit or leg of AC line power as the outlet serving the UPS.

You can test the battery with a DC voltmeter, though this cannot tell you much about the battery's ability to deliver enough electrical energy under a load. Disconnect it from the UPS for this test. A battery that has just been taken off the charger should measure anywhere between 12.5 to 13.1 volts or so, maybe slightly more or less.

Should the issue turn out to be a matter of voltage sag, it wouldn't be a bad idea to have an electrician inspect your wiring and outlets. The UPS sensitivity can also be adjusted downward, although this may require the use of PowerChute Personal Edition software on an ES model.

[Anonymous user]

Yes, im referring to the circuit breaker on the end of the unit.  I agree about your opinion that the battery may be bad.  Its been sitting there on trickle charge for several years and never been discharged (to my knowledge), so that would make sense.  The ES 550 does have the red and green LEDs, however, other than lighting briefly when you turn on the power switch, it has remained off.

Correct about the laser printer.  At the instant the fuser kicks in, the UPS kicks out.  The printer is plugged into the other receptacle on the same wall outlet as the UPS.  

I will plan on pulling the battery and checking the voltage.  In the event the battery is shot, is it reasonable to get a new battery for the unit, versus buying a complete new UPS?  I noted on the user guide that Schneider sells the replacements for it, but i haven't priced them yet.

[Anonymous user]

It's kind of odd that the LED would only illuminate briefly when you press the power switch. So long as the unit is on and line power is normal, the LED should be green and illuminated constantly.

I believe the replacement battery for your ES 550 is an APC RBC17. The genuine APC battery comes with a warranty, technical support, free recycling of your old battery and guaranteed compatibility. Its only drawback is that of cost: a totally brand new ES 550 costs only a little bit more. I don't know what APC's return policy on batteries is, should your UPS turn out to be broken.

Generic batteries are much cheaper, though not all of them are held to the same quality standards and you'd be using one at your own risk. A suitable generic battery would be a twelve volt, seven to nine amp-hour model.

If your UPS does turn out to be broken, I think APC still offers the "trade-UPS" program. This would provide a discount on a new unit and ensure the old one is properly recycled.

[Anonymous user · Accepted solution]

thanks for the info William, very helpful!

I would clarify re the LEDs.  the green one does in fact remain on steady while the unit is in operation, and goes out when the unit fails.  I was meaning that the red LED does not come on, either steady or blinking red, when the unit fails.