Bill Calculation
Example:
Suppose, a consumer consumes 1000 watts load per hour daily for one month. Calculate The Total Energy bill of the consumer if per unit rate is 9 (In $, £, €, INR ,Rs, DHR, Riyal etc) [Take 1 month = 30 Days].
Solution:
1unit = 1kWh.
So Total kWh = 1000 Watts x 24 Hrs x 30 Days = 720000 watts/hour.
we Want to convert it into Units, Where is 1unit = 1kWh.
So total Consumed units. 720000/1000…… (k=kilo=1000).
Total Units = 720.
Cost of per unit is 9.
So total Cost or Electricity bill= 720 x 9 = 6480. (In $, £, €, INR ,Rs, DHR, Riyal Rs: etc). You have Done
To determine the approximate power drain on your battery you will want to estimate the reserve power (amp/hour) and the amps the inverter will require to meet the continuous load demands of the appliance.
Calculating UPS/INVERTER Battery Backup:
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 have understand is that what ever may be the UPS wattage the battery backup will not vary. The battery backup will only vary depending on the battery Ah and the Usage Load.
To calculate UPS backup, We have a simple formula.
UPS Backup = Battery Ah * (Volts/Load) * (1/Powerfactor)
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 voltate 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
= 19 Minutes
Note: You can use the same formula for calculating the battery backup for home UPS or an INVERTER.
Battery Charging Current and Battery Charging Time formula
Here is the formula of Charging Time of a Lead acid battery.
Charging Time of battery = Battery Ah / Charging Current
T = Ah / A
Example,
Suppose for 120 Ah battery,
First of all, we will calculate charging current for 120 Ah battery. As we know that charging current should be 10% of the Ah rating of battery.
so charging current for120Ah Battery = 120 x (10/100) = 12 Amperes.
but due to losses, we can take 12-14Amperes for charging purpose.
suppose we took 13 Amp for charging purpose,
then charging time for 120Ah battery = 120 / 13 = 9.23 Hrs.
but this was an ideal case…
practically, this is noted that 40% of losses ( in case of battery charging)
then 120 x (40 / 100) = 48 …..(120Ah x 40% of losses)
therefore, 120 + 48 = 168 Ah ( 120 Ah + Losses)
Now Charging Time of battery = Ah/Charging Current
168 / 13 = 12.92 or 13 Hrs ( in real case)
Therefore, an 120Ah battery would take 13 Hrs for completely charging ( with 13A charging current).
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AC BTU Calculator This calculator uses metric measurements. It can help you estimate BTU heating requirements for various room dimensions. You can convert feet to meters below if needed
Power Calculations Power Calculations and formulas for quick conversions
Watts to amps calculator
|
Appliance
|
Watts
|
Appliance
|
Watts
|
Appliance
|
Watts
|
|
Central Air Conditioner NA
|
5,000
|
Electric blanket
|
200
|
Hedge trimmer |
450
|
|
Electric Clothes Dryer NA
|
3,400
|
Shaver |
15
|
Weed eater |
500
|
|
Oven
|
3,000
|
Waterpik
|
100
|
1/4” drill |
250
|
|
Hair Dryer
|
1,538
|
Well Pump (1/3-1 HP) |
480-1200
|
1/2” drill |
750
|
|
Dishwasher
|
1200-1500
|
Laptop
|
60-250
|
1” drill |
1000
|
|
Coffee Machine
|
1,500
|
Plasma TV
|
339
|
9” disc sander |
1200
|
|
Microwave
|
1,500
|
LCD TV
|
213
|
3” belt sander |
1000
|
|
Popcorn Popper
|
1,400
|
25” color TV |
150
|
12” chain saw |
1100
|
|
Toaster oven
|
1,200
|
19” color TV
|
70
|
14” band saw |
1100
|
|
Hot Plate
|
1200
|
12” black and white TV
|
20
|
7-1/4” circular saw |
900
|
| Iron |
1,100
|
Stereo
|
10-30
|
8-1/4” circular saw |
1400
|
|
Toaster
|
1,100
|
Satellite dish
|
30
|
Refrigerator/ Freezer** |
|
|
Microwave
|
500-1500
|
Radiotelephone - Receive
|
5
|
20 cu. ft. (AC) |
1411 watt-hours/day* |
| Room Air Conditioner NA |
1,100
|
Radiotelephone - Transmit
|
40-150
|
16 cu. ft. (AC) |
1200 watt-hours /day*
|
|
Vacuum Cleaner
|
500
|
LIghts
|
|
Freezer |
|
| Water heater |
479
|
100 watt incandescent bulb
|
100
|
15 cu. ft. (Upright) |
1240 watt-hours /day*
|
| Sink Waste Disposal |
450
|
25 watt compact fluor. bulb
|
28
|
15 cu. ft. (Chest) |
1080 watt-hours /day* |
|
|
|
50 watt DC incandescent
|
50
|
Cell Phone - recharge |
2-4 watts |
|
|
350
|
40 watt DC halogen |
40
|
MP3 Player - recharge |
.25-.40 watts |
|
Blender
|
|
20 watt DC compact fluor. |
22
|
|
|
Humidifier
|
300-1000
|
CFL Bulb (60-watt equivalent)
|
18
|
|
Video Game Player
|
195
|
CFL Bulb (40-watt equivalent)
|
11
|
|
Standard TV
|
188
|
CFL Bulb (75-watt equivalent) |
20
|
|
Monitor
|
150
|
CFL Bulb (100-watt equivalent) |
30
|
|
Computer
|
120
|
Heaters***
|
|
|
Portable Fan
|
100
|
|
|
|
Ceiling Fan
|
100
|
|
|
|
Can Opener
|
100
|
Waterbed Heater NA |
400
|
|
Curling Iron
|
90
|
Stock Tank Heater NA |
100
|
|
Stereo
|
60
|
Furnace Blower
|
300-1000
|
|
Cable Box
|
20
|
Clothes Dryer - Gas Heated |
300-400 |
| Clock Radio |
7
|
Well Pump (1/3-1HP) |
480-1200 |
|
