APC NS1080 (BN1080G) does not work after power outage

Wilferik · ‎2024-02-27

A few days ago we had a 9 hours power outage and, after power was restored my APC NS1080 (BN1080G) refused to work anymore.

Battery was replaced 3 months ago, so it is new... but the device barely responds to a power button press with a quick flash of the LCD backlight and nothing else. The breaker switch on the back doesn't seem to do anything.

Already tried to unplug it from the wall, right now it is with no devices connected to it, and when reconnected to power it simply does exactly the same: A brief flash of the LCD backlight and nothing else.

Any ideas, besides looking for a replacement?

Thanks!

Teken · ‎2024-03-01

The voltage you measured indicates the battery is fine / full. 👍 If the unit is still under warranty you should contact APC Technical Support to help troubleshoot the problem or if required initiate a RMA.

If the unit is out of warranty you can try a couple of things to see if it makes a difference.

Brain Dead: Unplug the unit from AC Mains. Disconnect the internal battery. Press and hold the power button until you hear a click / beep. This procedure resets the unit and attempts to clear any possible errors in the system. You may not hear or see a change from the unit as the brain dead procedure is not always integrated into a specific product line. Once this procedure is done reconnect the battery and apply AC Mains. Do not connect any loads to the unit at this time.

What do you observe?

Power On: Not all of the APC UPS models turn back on after a full depletion of the battery cells once utility power is restored. The user needs to press the power button for the unit to turn on & operate again. 🤦‍♂️🙁

NOTE: It’s important to understand there are different kinds of operational behaviours as it relates to how a unit will operate or behave under different environmental scenarios.

Cold Start: Each manufacturer defines this differently. As such my explanation will differ from vendor to vendor. If a unit indicates a cold start feature it means it can turn on from battery only while AC Mains is not present. This obviously assumes the battery is at the operational voltage level to do so.

Hot Swap: If a unit offers this ability it normally indicates the hardware can be started (turned on) without any batteries present.

Lower end models that do not have (hot swap) abilities will NOT turn back on if a battery is missing, low battery voltage, even when AC Mains has been restored / present. 🤢

Charging: Some units only charge while it’s turned on. Other units charge immediately if AC Mains is present. You won’t know until you validate the unit’s behaviour.

Pre-purchase: As stated up above it’s imperative to know and understand how a UPS will operate in any given state! ☝️ A simple test such as disconnecting the battery and applying AC Mains then pressing the power button. If the unit does not turn on it’s not hot swappable.

See Answer In Context

Teken · ‎2024-02-28

Assuming this is a high quality CSB (high discharge) battery inside. Measure the resting voltage of the battery with a multi meter.

What is the value? 🤔

Im going to assume you will see below 10 VDC. If so you can try to recharge the battery using an external 12 volt charger. Once the battery is fully charged insert the same back into the UPS.

The UPS should operate normally from there. 👍

NOTE: The behaviour you describe is because the battery voltage is too low. As such the UPS will not turn on and operate as expected. A standard APC battery can sustain (approximately) 260 full cycles before its service life is affected. The average service life is 3-5 years which depends upon usage and temperature. Repeated depletion (fully drained) cells will shorten the service life dramatically!

Let me know how this turns out. 👍

Wilferik · ‎2024-02-28

Thanks so much for the suggestion. This UPS takes a double battery (7Ah, 24V). After measuring voltage with a multimeter, it shows 27VDC.

I don't have a 12V charger available, plus the connector is recessed, very hard to reach.

Shouldn't the UPS charge the battery if it has low charge? Sounds illogical that if this happens the battery had to be taken out and charged externally.

Teken · ‎2024-03-01