Amp fuses and current draw

[marshallv]

Hello,

One more Q - if I have two amps and one has a 30Amp fuse and the other has a 20amp fuse, does that basically mean that as long as nothing is shorting and everything is working fine, those two amplifiers combined won't pull more than 50A?

Click to read more...

 

[jacko 10+ year member]

true statement.

 

[johnecon2001 5,000+ posts]

Depends on the amplifier maximum output at what volts the car is running at.

To find total amperage that can be drawn you take the volts that the battery outputs (check using a Digital Multi Meter) and multiply it by the maximum watts the amplifier is capable of.

And that is how many amp your amplifiers are capable of drawing.

 

[jacko 10+ year member]

ummm yeah if he has 20amp and 30amp fuses on his amp, he can't draw more than 50 amps without first blowing a built-in fuse on his amp...

 

[n2audio 5,000+ posts]

fuses aren't that sensitive. Metal element fuses take time to heat up, melt, and open the circuit. They can pass 2x their rated current for short bursts. Just because an amp has a 50A fuse doesn't mean it can't draw 51 or even 55A on a regular basis. Just the same - it may never draw more than 40 or 45.

You can use the amps' fuses as a guideline for power/fuse selection, but they don't tell you much specifically.

 

[squeak9798 5,000+ posts]

Depends on the amplifier maximum output at what volts the car is running at.
To find total amperage that can be drawn you take the volts that the battery outputs (check using a Digital Multi Meter) and multiply it by the maximum watts the amplifier is capable of.

And that is how many amp your amplifiers are capable of drawing.

Forgot to factor in amplifier efficiency. It may take a draw of 850w input to create that 500w output of the amplifier.

And, as n2audio said...fuses aren't very sensitive, and won't blow the millisecond current draw surpasses 50A (for example). It's very possible that the amp will pull more current in than it's fuse rating.

 

[Nikuk 5,000+ posts]

...........And, as n2audio said...fuses aren't very sensitive, and won't blow the millisecond current draw surpasses 50A (for example). It's very possible that the amp will pull more current in than it's fuse rating.

*cough*thedownfallofMeca*cough*

 

[squeak9798 5,000+ posts]

*cough*thedownfallofMeca*cough*

I'm not very familiar with them....they base amplifier output on fuse ratings??

 

[Nikuk 5,000+ posts]

I'm not very familiar with them....they base amplifier output on fuse ratings??

This years rules designate class by total fuse rating.

Take a guess at how much current can be passed trough an 80 amp AGU fuse for a 2 second burp... //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif

 

[squeak9798 5,000+ posts]

This years rules designate class by total fuse rating.
Take a guess at how much current can be passed trough an 80 amp AGU fuse for a 2 second burp... //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif

Hmmm.........>80A

//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

So, wouldn't it be smart to keep dropping fuse sizes till you find the absolute smallest one that will still allow the current draw you need? Or is it based off of "stock" fuse size?

 

[Nikuk 5,000+ posts]

So, wouldn't it be smart to keep dropping fuse sizes till you find the absolute smallest one that will still allow the current draw you need? Or is it based off of "stock" fuse size?

Nope, whatever fusing you have installed between batt & amp.

//content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif

 

[squeak9798 5,000+ posts]

:shakeshead:

You just wait.......people are going to be replacing the endcaps and such on the fuses so that they are running a higher amperage fuse then what it appears........