Coverting watts to amp draw

 

New member
Username: Goose5741

Post Number: 10
Registered: Dec-05
To figure out the amount of amps your system is drawing you take the watts, so say 500/12 since the system should be running at 12 volts minimum right??? You also need to allow 50-60 extra amps for your car to draw off of right???
 

Silver Member
Username: Theelfkeeper

Stockbridge, GA USA

Post Number: 978
Registered: Feb-05
Watts/Volts = Amps
and yes, usually about 50-60 amps for the car. but a better way is to figure out what amperage you are pulling for the stereo, and add that to the stock Alt's output and get a HO alt of that size. that way you'll be completely sure you have plenty of headroom.

so your 500 watts is about 40 amps

 

Platinum Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 10911
Registered: Dec-03
actually you're not figuring for efficiency.

after you divide watts by twelve, you need to multiply the result by 1.5 for a class AB amp or 1.2 for a class T or D amp.

then you have your current draw, roughly.
 

Silver Member
Username: Theelfkeeper

Stockbridge, GA USA

Post Number: 985
Registered: Feb-05
learned something new, knew class had an effect, but didn't know how to calculate for it.
thanks Glass
 

Silver Member
Username: N2audio

Lawrence, Ks USA

Post Number: 528
Registered: Mar-04
FWIW - these are max power test tone current calculations. The real world music current draw of an amp isn't even 1/2 that.
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