Battery backup system
A backup battery provides power to a system when the primary source of power is unavailable. Small backup batteries may be rechargeable backup batteries are kept charged by the prime power supply. A battery backup is a device that your computer or other device is plugged into in order to minimize the effect of electrical outages. Once an outage occurs, a battery backup goes into effect immediately to be able to power the computers and devices for a short period of time. This allows users to save the work they are currently doing while giving them the ability to shut down the computer properly until the electricity comes back on in a steady manner. Almost instantly, once the power flickers on or off, the battery backup will power your machine. The amount of time your device(s) will stay on depends on the size battery
Need of the backup system:
In Vigyan ashram has DICs and computer labs that run on MSEB supply When electricity is cut off while using the computer, you’ll lose any unsaved work that may be harmful and result in re-work. So to avoid this situation we need a backup system.
Objective: 1) To avoid irregular power outages 2) To avoid interruption while doing work 3) To save time
Steps:
Step 1: for the backup system, first take quotations from different shops and compare it.
Step 2:Then we select Esteem Electronics quotation 12 V, 60 Ah tubular batteries (POWER BAT) for the backup system.Made a quotation and compared notes for it. Step 3: The calculate total load for the DIC lab, Office and Computer lab.
Total wattage of the system:
| Sr. No. | Electronic Device | Quantity | Wattages | Total electric load in watt | Total electric load in VA |
| 1 | Computers | 10 | 300 | 2000 | 3750 |
| 2 | laptops | 8 | 60 | 300 | 600 |
| 3 | Bulb | 4 | 15 | 60 | 75 |
| 4 | Tube light | 2 | 30 | 60 | 75 |
| 5 | Fan | 2 | 30 | 60 | 75 |
| 6 | Router | 1 | 20 | 20 | 25 |
| 7 | Printer | 1 | 300 | 300 | 375 |
| 8 | Bio metric finger print | 1 | 40 | 40 | 45 |
| 9 | other (10%) | 401 | 401 | 501.25 | |
| 4417 | 5521.25 |
Back up time: Battery Details: i) additional further load expansion (Af) = 20% ii) Efficiency of Inverter (Ie) = 80% iii) Required Battery Bckup (Bp)= 2 hours iv) Loose Connection/ Wire Loss Factor (LF)=20% v) Battery Efficiency(n)= 90% vi) Battery Aging Factor (Ag)=20% vii)Depth of Discharge(DOD)= 50% viii)Battery Operating Temp= 46 degree Celsius
| Sr. No. | Temperature | Factor |
| 1 | 80 | 1 |
| 2 | 70 | 1.04 |
| 3 | 60 | 1.11 |
| 4 | 50 | 1.19 |
| 5 | 40 | 1.30 |
| 6 | 30 | 1.40 |
| 7 | 20 | 1.59 |
Battery backup time in hours can be calculated using following formula
Method 1: back up time = battery AH X Voltage of battery X N X Efficiency of battery / total load in watt N= Number of batteries needed
= 60 X 12 X 15 X 0.8 / 4417 = 8640 / 4417 =1.92hr
Method 2: Current= Total wattage (Watt) / Total voltage (V) Current = 4417 / 180 =24.54 A for one hour = 24.54 A ? = 60 So 2.45 hour
Step 4: Installation of batteries.
Quotation Comparison Note : https://docs.google.com/document/d/1WsH7y5Ou7017TGwngQqkmw_PRSaahO74eGBWjm4HQSU/edit?usp=sharing
Reference: http://blog.chapagain.com.np/how-to-calculate-inverter-battery-backup-time/
