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Bronze Member Username: EhowzPost Number: 14 Registered: Mar-06 | I have heard a bunch of different ways to calculate amperage draw from the cars electrical and they all give me different answeres. Does anyone know the right way to calculate the amplifiers draw? |
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Bronze Member Username: Van_manPost Number: 17 Registered: Mar-06 | Get an amp meter... Clamp it around the power wire near amp... |
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Gold Member Username: TheelfkeeperStockbridge, GA USA Post Number: 1678 Registered: Feb-05 | basically, its Watts RMS / Voltage = amperage of current draw. multiply that by 1.2 for Class D amp or 1.4 for class AB amp. that'll give you a general term to go by. clamp on amp meters aren't any more accurate. and you'd prob fry a DMM trying to pull that much amperage through it. |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 11495 Registered: Dec-03 | http://www.glasswolf.net/caraudio/charging.html that has the formula. also note these will give peak continuous draw. peak momentary draw can be up to three times that much current, and due to the dynamic nature of music and typical listening volumes, your general continuous current draw will be a small fraction of the peak continuous, and that amount is only measureable with a clamp meter. remember that from peak volume, every time you decrease audible volume by half (not 50% of the colume knob) you're decreasing power usage by a factor of ten times. that means at a quarter of the original full volume, you're using a hundredth of the original amount of average power. most people use maybe a couple hundred watts sustained for loud music in the car on a big system. |