UPS2000-G-2KRTS – -- - 2 pcs of UPS2000-G-2KRTS have the same load connected but they show different backup time

Publication Date:  2016-09-30 Views:  538 Downloads:  0
Issue Description

Why 2 UPS devices (UPS2000-G-2KRTS)  have the same type of load connected, but the Batteries show different backup time?

- UPS 1: 49 mins

- UPS 2: 2 hrs.
Handling Process

1. Check what is showing the display of each of the 2 UPSs:

è Customer answer:  The UPSs displays confirm what customer said: UPS1 (47 minutes) and UPS2 (2 hours). Both of them have almost the same Load connected:

2.   Check the <backup time limit> parameter 07 .

  è Customer answer: The backup time limit is setup right to <0> for both UPSs.

3.   What is the real Loads (Amps or Watts) connected on each of the 2 pcs. UPSs. For this it’s needed to measure the loads or to configure the RMS-SNMP01B WebUi interface for both UPSs and then  take screen shots to the WebUi monitoring page.  

  è Customer answer:  There are 2 Hp servers and 2 USG6000 firewalls connected to UPSs. They are devides over the 2 UPS devices so every device has 1 cord to UPS1 and 1 cord to UPS2. The 2 UPSs are uses as  redundant power supply .



4.   If it’s possible disconnect one by one the servers and the firewalls,  and then  check the power settings from  BIOS.

  è Customer answer:  There is 1 server (hp Gen8) wich causes the difference.  When unplug 1 power, the UPS backup time rises, and the other UPS shrinks in backup time.



Root Cause

From the WebUI screen shots I can see the real load connected on each of the 2 UPSs is different.:


-           - Load current = 1.4A

-          - Backup time= 49 min


-          - Load current=0.8A

-          - Backup time=146min

 This means the UPS2000-G-2KRTS with 49min backup time is not faulty. The discharge time is not linear and the discharge current is bigger (the power supply is smaller).

 For eg:  the below discharge battery table.: if the load current is 8.2A, the battery will be discharged in  4h;

If the load current is 10.8A, the battery will be discharged in 3h; and if the load current is 16.5A, the battery will be discharged in 1.5h.

So the battery discharge time is not linear in time ((10.8A*2=21.6A) is not equal with 16.5A) , even we multiply twice the time (1.5h*2=3h)



Reboot the server (VMWare ESX host) and check the power settings in the BIOS.
It was configured as Dynamic.

So, both of  the UPS2000-G-2KRTS are working perfect, there isn’t any problem on the 2 UPSs