Sudden total discharge with load

Anonymous user · ‎2021-06-28

I have an APC UPS 1500 that I use to condition my power and to act as a UPS should power go off on all the items on my rack - cable modem, router, couple of switches, NVR and a couple of other items. Front LCD says 23 % load. When I plug in a Samsung laser printer, briefly it shows about a 26% load, then I hear a click and the battery back up kicks in and the battery which previously said 100% now suddenly drops to zero and it clicks off -then clicks back on again and the devices that were suddenly powered off come back up and the LCD shows that the battery is recharging which only takes about 20 mins and then says 100% charged again?

Thanks in advance for your help.

Rich

BillP · ‎2021-06-28

Hi,

The discharge could be caused by the large load. When the load is applied to the batteries it could cause a rapid depletion which would cause the UPS and or NMC to report battery discharge.

It may also be a bad battery or battery pack. What does the system report as the battery voltage? The SMT1500 has qty 2 12 volt batteries. When each battery is good they should read around 13.5 volts when fully charged.

See Answer In Context

BillP · ‎2021-06-28

Hi,

What is the exact model number of the UPS? You will find that information on the bar code sticker on the back or bottom of the unit.

The description you provided sounds like the UPS is being overloaded by the printer. Laser printer while not in use pull a low amount of AC however when the unit first starts up or when a print is beginning the printer drawers a large amount of AC know as inrush. The inrush will overload the UPS and cause it to switch to battery and then drop.

The recommendation is to put the laser printer on a surge protector and not a UPS unless you size the UPS to meet the requirements of the laser printer and other attached equipment during peek draw.

Anonymous user · ‎2021-06-28

SMT 1500

I have had this printer plugged into this UPS before via another APC power strip to get more outlets in a low power demand situation. Why does the battery go to ZERO instantly?

BillP · ‎2021-06-28

Hi,

The discharge could be caused by the large load. When the load is applied to the batteries it could cause a rapid depletion which would cause the UPS and or NMC to report battery discharge.

It may also be a bad battery or battery pack. What does the system report as the battery voltage? The SMT1500 has qty 2 12 volt batteries. When each battery is good they should read around 13.5 volts when fully charged.