Diagnosing fuse blown

[plao]

Hello,

Disclaimer: I am a total car audio/electrical noob, not professional, and working with old/free equipment. 

Here is the setup: From the battery (14.2V tested at the amp, a  30A AGU in-line fuse to 8awg power wire, then this wire is spliced and another 8awg wire is added. The two 8awg wires then run to 2 separate amps - a speaker amp, and a sub amp. The speaker amp is 4 channel, but only running two channels to some cheap 6.5"  4ohm speakers (possible rated at 160W RMS) and the other two channels are unused. This speaker amp is putting out 180w RMS Pwr/CH 4 ohms

The sub amp is wired for a bridged configuration to a mono 18" 4 ohm sub which outputs 560W RMS, 4ohm

It was all working fine for a few days and then I started testing the levels/limits, and once I upped the gain significantly and was at the distortion limit, I blew the 30A fuse at the battery. No amp fuses blew and no damage was done to the equipment. I replaced the blown fuse with a spare fuse that was rated at 80A and everything seems back to normal but I am not turning anything up until I figure out the problem. I think I need to get some  4awg power wire, a distribution block, more fuses, and use some of the 8awg wire I already have and this should solve the issue.

Can anyone give some direction and also let me know what rated fuses I will need and how many?

Thanks,

P

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[keep_hope_alive Premium Member]

You need a smaller fuse, maybe 60A but not 80A given the wire you used.  It's pretty easy to pop a 30A fuse.   I'd try a 60A fuse and leave the wiring alone and you will likely be fine.

 

[plao]

Thanks for the reply. I think your right about the 60A fuse for the 8awg wire, but what about the fact that I have running two amps? Does the inline fuse at the battery handle the total of both amps?

They aren't that powerful but still I'm wondering about two amps on 8awg wire with on in-fuse. Both amps have two internal fuses each. . The amp fuse on the sub amp has 2 x 25A fuses (25+25 = 50) and the speaker amp has 2 x 40A fuses (20+20 = 40 amps). That is 90A total so don't I need to match that or slightly exceed that maybe using a 100A so to protect the vehicles battery and charging system in case one of my amps fail?

Thanks,
plao

 

[plao]

You need a smaller fuse, maybe 60A but not 80A given the wire you used.  It's pretty easy to pop a 30A fuse.   I'd try a 60A fuse and leave the wiring alone and you will likely be fine.

So I just finished installing 4awg to a 100A in-line fuse. This then goes to a distribution fuse block and then out to 2 8awg out. Each of these smaller fuses are rated at 60A. 

Should I be okay with no wires catching on fire, no amps frying, alernators frying, i.e., will the fuses blow first if anything like a short to ground happens?

Thanks,
Plao

 

[wew lad 5,000+ posts]

So I just finished installing 4awg to a 100A in-line fuse. This then goes to a distribution fuse block and then out to 2 8awg out. Each of these smaller fuses are rated at 60A.

Should I be okay with no wires catching on fire, no amps frying, alernators frying, i.e., will the fuses blow first if anything like a short to ground happens?

Thanks,
Plao

Yes, retighten your connections and check for corrosion in 3-6 months