Is fuse rating same as amperage draw?

[nas786 10+ year member]

I'm on the usamps website looking at the 400x, and it says it has a fuse rating of 50A. Does that mean that you need an alternator that puts out at least 50A in order to run it without problems? (assuming i don't use any capacitors or wind the alternator or anything like that)

Also, in general, how can you find the draw of amps? USamps is the ONLY product i've seen this figure for.

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[HowLowd 10+ year member]

Multiply the amp RMS rating by 2

..ie: 1Kw X 2 =2Kw

Total wattage 2Kw = 166.66A draw

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12V

This formula would give what your peak current draw COULD be. in a fit of maximum musical reach it would pull this much. hopefully you have a little more than that available.

 

[nas786 10+ year member]

huh?

so, is it like this..

(total wattage)(2)=166.66A draw

something seems to be missing...

 

[ToyTundra 10+ year member]

divide by 12.0 or 14.4 or whatever your vehicle runs at. Thats max current draw at 100% efficiency, there's a thread on here that described it well....

 

[JimJ 5,000+ posts]

Assuming the amps are 100% efficient, which they are anything but //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[ToyTundra 10+ year member]

i read in a US amps online manual that 7.5 amps per 100wrms is a realistic value, but i have no proof to back that up...

 

[JimJ 5,000+ posts]

i read in a US amps online manual that 7.5 amps per 100wrms is a realistic value, but i have no proof to back that up...

Completely dependent on amplifier topology //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[ToyTundra 10+ year member]

I guess everything can't be easy. Thanks Jack frost

 

[HowLowd 10+ year member]

lol sorry, was on the way out when i posted

 

[RandyJ 10+ year member]

Multiply the amp RMS rating by 2
..ie: 1Kw X 2 =2Kw

Total wattage 2Kw = 166.66A draw

----------------

12V

This formula would give what your peak current draw COULD be. in a fit of maximum musical reach it would pull this much. hopefully you have a little more than that available.

You have to factor in amplifier efficiency if you are going to use this....

 

[n2audio 5,000+ posts]

to be perfectly honest you really can't determine the REAL current draw of anything because the biggest factor is your listening habits.

If you have a 1000w class D amp, but you rarely listen to it at high volume and don't play a ton of heavy bass music there's a good chance it never draws more than 15-20A rms.

On the other hand, if you have an 800w class a/b amp that's slamming non-stop it might draw 60A or so.

All things considered I think the 7.5A/100w is a pretty good rule of thumb - I've also seen 10A/100w , but even then - w/o a real-time power measurement you don't know how much wattage you're actually using.

There are so many variables with current draw...that's why the standard response -- "Hook it up and see how it runs," is really the only way to know for sure.

 

[nas786 10+ year member]

^^yea, i might end up doing that, the thing is that I have a brand new amp, its a usamp 1000X, class a/b running 1000 watts, and I would rather sell it brand new than used (sell it assuming that its too much for my car), which is why i'm kinda debating wether I should hook it up or not. My alt gives about 90amp.