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Question
`How to calculate the ups battery back up? give the formula.`
Question Submitted By :: Electrical-Engineering
I also faced this Question!!     Answer Posted By

# 1
numbers of battery * ah of battery /output kva*130
34*200 /160*130
6800/20800
0.32 hours .

 Is This Answer Correct ? 54 Yes 19 No
Subir Kumar Manna

# 2
T = N.V.X / VA

T= Time in Hours
N = No. of batteries
V= Voltage of Battery
X= Amp-Hour of the Battery

 Is This Answer Correct ? 37 Yes 7 No
Ananth

# 3
V*AH/VA
 Is This Answer Correct ? 28 Yes 15 No
Dhruvendra

# 4
To get one hour battery backup:

BATTERY AH = 1000 × VA × PF /( NO. OF BATTERY × BATTERY

 Is This Answer Correct ? 3 Yes 0 No
A. Dutta

# 5
Time=ups efficiency*battery efficiency*battery low volts*battery AH/ups output(watts)
 Is This Answer Correct ? 8 Yes 6 No
Balajiram

# 6
backup formula= KVA/DC LOW *POWER FACTOR

FOR EX:2 KVA/120 DC VOLT(SYSTEM VOLT)OUR MAINTAINED POWER

FACTOR (0.8 P.F),PER BATTERY=12V(DC LOW=10.8),HERE USING THE

SYSTEM VOLT=120V SO,10 BATTERIES-10*12=120V

DERIVATION : 2000/108*0.8

AH=14.81(APP.17 AH BATTERY) given 30 minutes backup

 Is This Answer Correct ? 6 Yes 5 No
Sathiyanarayanan

# 7
back up( in hours)= system dc volts x AH rating(

 Is This Answer Correct ? 1 Yes 0 No
Narayanarao.s

# 8
backup time=(kva rating*power factor)!dc low of system
 Is This Answer Correct ? 3 Yes 3 No
Prakash Dhanshetty

# 9
Calculating the UPS and Battery Backup Time
Before calculating the Battery Backup, let us know a few
factors that vary battery backup.
For and UPS with 875Va we can us a maximum load of 640
watts 677Va we can us a maximum load of 540 watts
The main thing we should understand is that whatever may be
the UPS wattage the battery backup will not vary.
The battery backup will only vary depending on the battery
To calculate UPS backup, we have a simple formula.
UPS Backup = Battery Ah * (Volts/Load) * (1/Power Factor)
Example: Let us calculate the backup for a system UPS
Load is the usage power, suppose we are running a PC then
the load is around 300 watts
Power Factor varies for device to device, the average power
factor is 1.4
Voltage is the voltage of the battery.
For a single battery the voltage is 12v.
If the batteries are connected in a series Voltage = 12 *
no. of batteries.
Battery Ah is the battery ampere used for the ups,
System UPS battery AH is 7
Then Battery Backup = 7 * (12/300) * (1/1.4)
= 7 * (0.04) * (0.7)
= 0.19 hours
= 11.4 Minutes
Note: You can use the same formula for calculating the
battery backup for home UPS or an INVERTER.

 Is This Answer Correct ? 0 Yes 0 No
Sayyed Fayyaz Ahmed

# 10
UPS / Invertor Battery Backup Time =
----------------------------------

Batt Voltage X No.of (Batteries) X Ah (Single Battery) /
Total Load (Watts) = No.Hours Backup

Example :- 12v X 20(Batteries) X 200Ah (Single Battery)
/ 6000 (Watts) = No.Hours Backup

48000 / 6000 Watts = 8 Hours Backup

 Is This Answer Correct ? 0 Yes 0 No
Bhushan

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