Understanding the math of electrical loads
m |
|||
| Line 1: | Line 1: | ||
| − | + | =Formula= | |
This basic formula P= I X E, just think of that tasty pie. P (power in watts) = I (current in amps) X E (electromotive force volts) | This basic formula P= I X E, just think of that tasty pie. P (power in watts) = I (current in amps) X E (electromotive force volts) | ||
| − | =Using the formula== | + | ==Using the formula== |
So, how much current at 12 volts does a pair of 55 watt headlights consume? Algebra lets you turn the formula around to find the unknown. 110 watts = I X 12 volts, whip it around you get 110 watts divided by 12 volts = 9.17 amps. If you have a battery rated at 65 amp/hour you can see the time at the above load of 9.17 amps to complete battery exhaustion would be about 7 hours. (Not counting the Puekert effect, which in simple form just means the heavier the current draw the lower the a/hr for the battery). Now comes some fun calculations, hp and watts, both units of work. Let's say some aftermarket, high performance starter motor manufacturer claims he has a 4 hp starter -- can you determine if this is reality? Math again. 1 hp = 746 watts, so 4 hp = 2984 watts divided by 10 volts (your 12 volt battery under the load of the starter) = 298.4 amps. | So, how much current at 12 volts does a pair of 55 watt headlights consume? Algebra lets you turn the formula around to find the unknown. 110 watts = I X 12 volts, whip it around you get 110 watts divided by 12 volts = 9.17 amps. If you have a battery rated at 65 amp/hour you can see the time at the above load of 9.17 amps to complete battery exhaustion would be about 7 hours. (Not counting the Puekert effect, which in simple form just means the heavier the current draw the lower the a/hr for the battery). Now comes some fun calculations, hp and watts, both units of work. Let's say some aftermarket, high performance starter motor manufacturer claims he has a 4 hp starter -- can you determine if this is reality? Math again. 1 hp = 746 watts, so 4 hp = 2984 watts divided by 10 volts (your 12 volt battery under the load of the starter) = 298.4 amps. | ||
Your Privacy Choices