How much of fuse rating is drawn, + is it safe to assume Im drawing this much current

[RSDXzec 10+ year member]

Currently running a class AB amp at 400wrms at 2 ohms. It has 60Amps worth of fuses on it as well as a 60Amp fuse on the wire. How much current would it really use? (constant 0db 50hz tone)

The class D amp I'll be using soon (APSM-1500) puts out 1500wrms and although it doesn't have fusing on it, it comes with a 100 amp fuse for the wire. I plan on drawing 1000wrms tops from it and as that is 2 thirds of what it's rated for, could I assume I wouldn't draw more than 66.66Amps?

I'm assuming there's a linear relationship here between power and current draw.

Cheers.

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[murph 10+ year member]

Currently running a class AB amp at 400wrms at 2 ohms. It has 60Amps worth of fuses on it as well as a 60Amp fuse on the wire. How much current would it really use? (constant 0db 50hz tone)
The class D amp I'll be using soon (APSM-1500) puts out 1500wrms and although it doesn't have fusing on it, it comes with a 100 amp fuse for the wire. I plan on drawing 1000wrms tops from it and as that is 2 thirds of what it's rated for, could I assume I wouldn't draw more than 66.66Amps?

I'm assuming there's a linear relationship here between power and current draw.

Cheers.

First amp depends... If it runs on 1 ohm it most likely would or if the amp is underrated than it would also use nearly every amp of fusing. Some cheaper amps are overfused to make them look more stout. If you are running 1k on the APSM I would fuse for 100A.

 

[RSDXzec 10+ year member]

First amp depends... If it runs on 1 ohm it most likely would or if the amp is underrated than it would also use nearly every amp of fusing. Some cheaper amps are overfused to make them look more stout. If you are running 1k on the APSM I would fuse for 100A.

The first amp is only stable down to 2 ohms and as far as I know this can't put out much more than 400wrms, it's a cheapo brand so I wouldn't expect much. How close to 60Amps would you say it could get?

If the apsm recommends 100amp fusing for 1500watts shouldn't it use fairly less at 1000watts? (I will be using the 100Amp fuse provided by them either way).

 

[murph 10+ year member]

The first amp is only stable down to 2 ohms and as far as I know this can't put out much more than 400wrms, it's a cheapo brand so I wouldn't expect much. How close to 60Amps would you say it could get?
If the apsm recommends 100amp fusing for 1500watts shouldn't it use fairly less at 1000watts? (I will be using the 100Amp fuse provided by them either way).

Maybe 50A but most likely 40A but the amp is probably horribly inefficient. You don't have to fuse according to how many amps your amp puts through the wire you can fuse to the max amperage your wire can handle for example 125A to 4 gauge wire.

 

[Bettr n' Revrse 5,000+ posts]

Yep always fuse for the wire

 

[RSDXzec 10+ year member]

Maybe 50A but most likely 40A but the amp is probably horribly inefficient. You don't have to fuse according to how many amps you amp puts through the wire you can fuse to the max amperage your wire can handle for example 125A to 4 gauge wire.

I would take a guess 50Amps sounds right, I get decent vdrop at idle speed on my 85A alt.

I know wire fusing is based on what the wire can take but if the Audiopipe amp is rated at 1500watts why would they supply a 100A fuse with it? One would assume it could put out that much without going over 100A if that's what's supplied with it (considering people have clamped it to put out rated).

 

[murph 10+ year member]

I would take a guess 50Amps sounds right, I get decent vdrop at idle speed on my 85A alt.
I know wire fusing is based on what the wire can take but if the Audiopipe amp is rated at 1500watts why would they supply a 100A fuse with it? One would assume it could put out that much without going over 100A if that's what's supplied with it (considering people have clamped it to put out rated).

Mmats 3k has 100amp fusing and puts out 3k... Fuse rating doesn't always mean it puts out near fusing. Most quality amps are fused far below their max wattage output. (at rms)

 

[RSDXzec 10+ year member]

Mmats 3k has 100amp fusing and puts out 3k... Fuse rating doesn't always mean it puts out near fusing. Most quality amps are fused far below their max wattage output.

hmm... that's a bit inconvenient. I had no idea.

Cheers, I'll have to look into it a bit more.

edit: checking reviews online and people are powering 1500wrms with the 100Amp fuse.

http://www.vminnovations.com/Product_16149/Audiopipe-APSM-1500-1500-Watt-Mono-Mini-Amplifier-.html

these reviews are to be taken with a grain of salt though...

 

[smoka 10+ year member]

You fuse for the wire size only at the battery. This protects the wire from catching fire.

You fuse at the individual amps to protect them from overloading.

Don't listen to these morons here who have no idea what they are talking about.

In general, amps are designed with a fuse that is 125% over their max output. So if your amp has a 100a fuse the most you should expect out of that amp (at 12v in perfect conditions) is 960W.

Electrical engineers and Electricians use the standard "125% over max load" rule when sizing circuit breakers or fuses. Feel free to look that up.

 

[smoka 10+ year member]

Mmats 3k has 100amp fusing and puts out 3k... Fuse rating doesn't always mean it puts out near fusing. Most quality amps are fused far below their max wattage output. (at rms)

You must go through alot of burned fuses.

 

[quackhead 10+ year member]

You must go through alot of burned fuses.

it generates the extra power..you know, it is Mmmmaaattss

 

[murph 10+ year member]

You must go through alot of burned fuses.

Never burned one fuse. My 1/0 is fused at 250a and when it splits to 4 gauge it is fused to 80a ATM.