Fuse/breaker value recommendation on Zed Deuce amp

[americannight 10+ year member]

Hey guys, I thought I'd post this here under electrical help. For background on my build you can check out my build log here:

http://www.caraudio.com/forums/car-audio-build-logs-cars-trucks-suvs/559208-volvo-s60-build-resurrected-old-school-8.html

You'll see that I'm running one of the Zed Audio THE DEUCE amps to the IDQv12 speakers bridged mono into the 4 ohm load.

Originally I had a 60 amp fuse on that amp. Every few days I'd pop a fuse. The amp is rated at 800 watts mono into 4 ohms. It's a class A/B amp so I'm guessing it's roughly 60% efficient. It's also under-rated. It will do the 800 watts and then some (Zed tells me it has benched at 1000 watts mono take that for what it's worth).

Fuses don't blow right away, they typically will do short bursts above their rated value for a while and then they will pop. So I'm not surprised this was happening. 60A is pretty light for a class A/B amp of this size and design.

So yesterday I replaced the 60A fuse with an 80A Stinger breaker. Now it pops more frequently than the fuse did. I was a bit surprised to see this but then again not really given that a breaker will pop quicker than a fuse. Also whereas fuses will do more than their rated current for short bursts, many breakers will actually pop a tick BELOW their rated current.

If I look at what's going on here using Ohms Law, it seems pretty clear that if this amp really does do the 1000 watts peak, then an 80A breaker will not be enough.

Watts = Amps x Volts

So Amps = Watts/Volts

Factoring in 60% efficiency, I get Amps = Watts/Volts (.60)

Assuming 14.4V I get Amps = 1000/14.4(.6) = 115.74 Amps

Based on this, my thought is to go to a 100 Amp stinger breaker and also back off the gain just a tad.

Curious if you guys have any recommendations or suggestions here.

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[brandonkain82 10+ year member]

Either that or u got something that is shorting out.

 

[americannight 10+ year member]

That is definitely something good to check just to make sure. I will have a look again at all connections and make sure there are no shorts. It is also worth mentioning that I need to upgrade my charging system. The stock 120A alternator is not sufficient for this system. I have an email out to DC power to see what they can do for me. volvo isn't listed on their website.

 

[Kingstroker 10+ year member]

I would stick to a factory recommended fuse. Breakers tend to be less effective the more they are tripped, don't know of any company that recommends breakers for there amps.

 

[americannight 10+ year member]

I would stick to a factory recommended fuse. Breakers tend to be less effective the more they are tripped, don't know of any company that recommends breakers for there amps.

Thanks for the recommendation. The more I think about this the more I conclude that I need to fix the root of the problem which is an under sized charging system. The amp will operate more efficiently at a constant 14.4V, probably to your point closer to the rated fuse. The Zed manual states that I can increase the fuse to 80A if needed. Likely the 80A breaker or fuse will suffice once the charging system is up to snuff and I maybe need to back off the gain just a bit. With the subs in the trunk it is realistic that there could be some clipping that I am not perceiving from inside the vehicle. This is a fresh system for me so I'm still working out the bugs and getting to know the equipment.

 

[Kingstroker 10+ year member]

fuse my wire close to battery according to wire size and one close to the amp