Answer / k.prakashchandra

Energy stored in a battery = AH x V watthour.Multiplying
with number of batteries you get total energy stored in watt
hour.Divide this by load in watt to get the backup time in
hours ,ignoring efficiency,losses and residual stored energy.

Answer / m.b.parthasarathy

The formula is as follows.

1. To find battery back up time : Battery AH X Battery volt X constant factor is divided by load(in watts). Perhaps if you have 100ah battery and the load is 500watts you can find back up time as follows.
EX: 1ooAH X 12V X 0.85 / 500
100AH X 10.2 / 500 = 2hrs.

2. To find battery AH : Back up time X load is divided by Battery volt X constant factor.Suppose you need 2hrs back up time with 500watts load, yu can calculate battery AH as follows.
EX: 2 X 500 / 12 X 0.85
1000 / 10.2
= 98.03AH. Commercially available 100AH battery only.

Answer / j.prakash

after the load and running time is decided the battery bank
size can be calculates the first calculation is to divide
the laod in watts by 10 for 12 v systems or 20 for a 24v
system ....

resulting in the number of amps required from the batter
bank..

AN Example of this calculation is:

1.total watts=1000watts.
2.amps from 12v battery =1000/10=100amps DC.

FOR A 12V BATTERY 100AMPS DC*3H=300AMPS HOURS(AH)

What is the difference between Off line UPS and Line interruptible UPS?

1 Answers   Etisalat,

---

Why is the generator rating always in kVA and motor rating in kW?

7 Answers  

---

plz send me the placement interview question and answers of whizchip(technical and apttitude)..i have an interview in next.

0 Answers  

---

can u please mail me the syllabus for GET exam for damodar valley corporation?

0 Answers  

---

hi this is hema, r there any books in particular for the preparation of the APPSC-A.E.E(electrical), if so please mail me the names ... thank u .

0 Answers   Vizag Steel,

---

---

What is 2P*0.5 sqmm screened copper cable and what is the use of it..?

1 Answers  

---

how much current capacity 250 amp. mccb please tell me about whats are the reasons to trip 2 or 3 times in a night. and what are the steps to short out this problem

1 Answers   Havells,

---

Why does the radius of armature is less than the radius of pole shoe?

0 Answers   ABB,

---

What is the value of specific gravity in charged lead acid batteries.

11 Answers  

---

what is the vvvf in the dumbwaiter?? or lift. what is the actual process?/

0 Answers  

---

What are the advantages of using distance protection schemes as opposed to normal overcurrent/ earth fault protection on high voltage feeders.

0 Answers   Eskom,

---

in cable joints procedure what electrical problems have been solved out ?

1 Answers  

---