There is a good chart of wire recommendations at http://www.redrival.com/ixlnxtc24/wiresize.htm The lengths and gauges are calculate for 0.5V drop. If you know any electricians they pretty much all have a little book with lists of voltage drops per foot, per current draw (Amps, you can caculate this roughly if you know the wattage of the bulbs. (Wattage) divided by 12 = Amperage. Not exact, but good enough for this application). Here is the reason why this matters (Again, not 100% accurate, but good enough for government work ;): Let's talk about a 1Volt drop. *If you have a pair of 60 watt bulbs running it would be a total of 120 watt potential draw. * Power (Watts) = Amperage x Voltage 120 Watts = A x 12Volts A = 10 amps (How much current they would draw at 12volts) * Now calculate the resistance of the bulbs so we can see how Voltage effect this power output. Voltage = Amperage x Resistance 12 Volts = 10 amps x R R = (12) divided by (10) = 1.2 ohms * How much current would these bulbs draw if they only received 11 Volts (We can do this because the resistance of the bulbs will not vary with voltage)? Voltage = Amperage x Resistance 11 Volts = A x 1.2 ohms A = 9.17 amps * Finally, how much power (watts) are our two 60 watt bulbs putting out now? Power = Amperage x Voltage Power = 9.17 amps x 11 volts Power = 100.87 watts As you can see, your 60 watt bulbs would be functioning like a pair of 50 watt bulbs. Mike B |
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