"TRU POWER"

ChevyBoy
10+ year member

Junior Member
I know this question has been asked before but how can an amp with a 80 amp fuse make 1400 watts of power. Like for instance a pg tantrum 1200..or maybe a hifonics with a 120 amp fuses creates 1500 watts....i know some amps are more efficent than others but i thought it took 10 amps to create 100 watts of power..and so if an amp had such a small fuse ,shouldn't they blow after a couple of minutes.I see amps like rockford fosgates 1501 and jl 1000/1 and there rated correctly with 150 amp fuses and 100 amp fuses...I'm not doubting the pg tantrums power ,maybe i'm just confused somewhere?????

 

Logikalliquid
10+ year member

CarAudio.com Elite
979
0
SoVA
well watts is amps x volts first off. that still leaves you a little short of power even at 14.4v though. i've noticed this discrepancy before as well and still havent found the answer. hopefully someone can point it out.

 

namster44
10+ year member

Great White North
636
0
Canada
Fuses are just a estimate. The amp in question can actually pull more current. And assuming most d class amps are about 70%(give or take) efficient. 1500 = .7(14.4 * 149).

Just look at the D2 Earthquake amp, modded it can do about 2500 watts with 60(could be wrong, but I know it's low) amps for fuse(s).

 

helotaxi
5,000+ posts

Kilroy was Here
It all has to do with the way a fuse is rated. The standard for a fuse is 110% of rating for 4 hrs, 135% for a max of 60 minutes and 200% for a max of 2 minutes. Based on that an amp can make a lot more power than its fuse rating would seem to allow, it just can't do it forever.

 

maylar
10+ year member

Electrical Weenie
3,498
1
Connecticut
Standard practice is to fuse a circuit with 150% of actual expected load current. Some designers will go 125%, some 200%.

Power input = power output / efficiency. If an amp outputs 1000 watts and is 60% efficient then it's input power is 1000/.6 = 1666 watts. The current it would draw at 14.4 volts would be 115 amps. I would expect a 150 amp fuse at least.

2 channel amps that can be bridged ususlly have separate power supplies for each channel. The example above might have 2X80 amp fuses.

To answer your original question, 80 amps at 14.4 volts is 1152 watts. Even if the amp was 100% efficient (impossible), you can't get 1400 watts output from it without blowing the fuse. Assuming a 125% fuse overload and 80% efficiency (Class D) the amp is probably designed for about 750 watts RMS.

Note however that music has about a 5:1 peak-to-average ratio. The amp could very well be capable of 1400 watts and the designers figured the fuse rating conservatively based on expected duty cycle. A slow-blow fuse needs about 10 seconds at rated current before popping.

 
Activity
No one is currently typing a reply...
Old Thread: Please note, there have been no replies in this thread for over 3 years!
Content in this thread may no longer be relevant.
Perhaps it would be better to start a new thread instead.

Similar threads

i know that don’t change nothing thought i would share just let me know k if u want to text or email about it i will send u my info
6
578
I think the guidelines want members to have a picture with your forum username and current date in the picture to avoid scammers. :)
1
370
LMAO.yep,this setup going on over 9 years.appreciate the inspirational quote although i dont take part in water boy memes.
10
602
I have created a post with all related information regarding the build under this link: https://www.caraudio.com/threads/2000-camry-build.614208/
50
3K
This type of controller will work on any amplifier (or specific channel) as it is inline with the RCA connections and functions entirely as volume control knob increasing or decreasing the...
9
743

About this thread

ChevyBoy

10+ year member
Junior Member
Thread starter
ChevyBoy
Joined
Location
Tallahassee,FL
Start date
Participants
Who Replied
Replies
9
Views
884
Last reply date
Last reply from
maylar
IMG_5559.jpeg

Buck

    Feb 22, 2024
  • 0
  • 0
IMG_5558.jpeg

Buck

    Feb 22, 2024
  • 0
  • 0

Latest topics

Top