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# Electrical Formulas

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## W=Q x E

```Where W = Watts is the energy absorbed in a
electrical circuit in watts per second
```
```     Q = Coulombs is the quantity of electricity
which is transferred between two points
```
```     E = Voltage or Electro Motive Force
```

Dividing both sides of the equation by time it takes for the quantity Q to flow in a circuits becomes:

```     W/T = (Q x E)/T   or  P = I x E
```

Where P Is the Power in amount of time.

```     I is the rate of flow in seconds or hour
```
```     E is the e.m.f
```

Simplify to:

```     W = I x E   (watts or energy - no time)
```
```     Wh = I x E  (watt hour - amount for 1 hour)
```

### Example:

```     If you are charging a battery pack at 240 volts AC at 50 amps AC, then 240V x 50A = 12 KW  or 12,000 watts (input into the charger)
```

If you charge for 1 hour, than this will become 12 KWH or if you charge for 1 second, than the cost of Power will be 12 Kw/3600 secs (3600 seconds in a hour).

If you drive the EV for one hour at 50 battery amps and 100 volts, than you will use about 50 ADC x 100 VDC = 5KW Per Hour or 5KWH.

The HP (horsepower) use, where 1 HP = 746 watts:

```     HP = Watts/ 746  = 5000 / 746 = 6.7 HP
```

If you look on some motor labels on a motor, or in the specifications of that motor, You may see data as:

```165V @ 175A   32HP   6000 RPM    83% Effiency.
```

To calculate this:

```W = 165V x 175A = 28,875 watts (input energy)
```
```   28,875 x .83 = 23,966 watts (output energy)
```
```HP = 23,966 / 746 = 32.1 HP
```

Roland