View Full Version : calculate car amp draw?


Luc1f3r
12-28-2008, 09:56 PM
ok, how do i figure out how many amps my car is pulling? im needing to buy a power converter to run my car at indoor shows. i know im going to get an Inteli brand supply but i need help figuring out what size i need.

i want to power:

1500 watt amp
450 watt amp
strobe kit 1 (15 amp fuse)
strobe kit 2 (15 amp fuse)
strobe kit 3 (15 amp fuse)
strobe kit 4 (10 amp fuse)
light kit 1 (3amp fuse)
light kit 2 (3amp fuse)
lights (5amp fuse)
pioneer D3
3 tvs (i think all are 5amp fuses)
dash lights
dome lights (4)

now, if the math is as simple as just adding fuse ratings the 60amp kit would barely cover my strobes alone... so how do i figure this out? i dont really care TOO much about the stereo working at showoff volume but it would be nice to have some sound coming from my car...

Dr_Isotope
12-29-2008, 03:51 AM
The rating of a fuse is usually substantially higher than the requirements of the device-- a headlight bulb only draws around 3A constant, and it puts out at least 55w. By comparison, strobes, LEDs, and monitors draw a minimal amount of power. The killer will be the amplifiers, unless you plan on only running them at a low to moderate volume. Two amps with that combined rating could easily pull 100A when running at even 3/4 of capacity, and no off-the-shelf power supply is going to keep up with that.

BZinn1
12-29-2008, 04:30 AM
You definatly need over a 100 to run amps on a power supply unless you do not turn it up.I bought a 150A power supply and it pushes all my stuff such as lights and amp.not sure how long it will last if used for a long time as it does warm up,I may need a bigger one,but they get spendy over 150A.

Luc1f3r
12-29-2008, 02:20 PM
yeah, ill prolly just be running my stereo at 1/4 volume. just enough to hear what is being said in the movie that is being shown on the screens. its not like you would really hear anything coming from my car at a HIN event anyway.

kileil
12-30-2008, 04:54 AM
Ohm's Law:

http://www.the12volt.com/ohm/page2.asp

since you have a mix of wattage and amperage (absolute peak OMG the car's going to light on fire fuse-rating) you're going to have to break it down and add.