Sub amp turns off?

[Ray De Man]

Hi guys, got slight and confusing problem. Just playing music then sub amp will go off. It's done it twice now, 1st time after long periods driving and the 2nd was in the first 5 minutes and sub amp (Alpine) would go off. I have a volt meter on the sub amp and it was showing 8.6 volts with engine running. I checked fuses and connections but all look ok. I switched of car turn back on after 5-10 mins and all is fine again. I don't get it! One thing though I noticed was... The power wire from batt fuse to second fuse for amp was quite warm but wire from second fuse to amp was cold. Is that normal? Stereo amp works fine doesn't go off.

Can some tell me what's wrong?

[Ray De Man]

Oh forgot to say, when sub amp is on and working well with engine runningat, volt meter is showing between 13.8-14.6 volts but when low bass hits it goes down to 11.3 volts. Protection light does not come on nor is any fuses blown.

[HCVP]

How many fuses exactly do you have between the battery, and the amp?

What guage are you using for the power cable?

Where do you have your amp earthed off, what guage is your earth cable, and how long is your earth cable?

[Ray De Man]

I have two between batt and amp.
Power wire is 2 gauge.
Earth is also 2 guage and is bolted into chassis. It is 1 1/2 foot long no more.

[HCVP]

I haven't done a serious install in a long time, but i've only ever used one inline fuse, between the battery and the amp.I'm curious as to why you have 2, but i couldn't say whether or not that would have any impact, but for the short amount of time it would take you to remove one of those fuses, i definately give it a go.

[blky]

i use 2 for my amp setup, only because my power cable wasnt long enough to where i wanted to mount my amp haha so i used it as an extension, so i dont think that it would have an impact here?

is your amp overheating and shutting down by itself?? have you tried feeling its temperature? maybe even try replacing the 2nd cable that heats up too

[holdenboy]

Sounds like a poor connection along the power / earth cabling.

Double check your connections at the battery, the fuse holders, sometimes the fuseholder itself is the cause, contacts can become loose and not make a good connection. Also check the power / earth connections at the amp and the earth connection to ground, make sure its tight and making good contact.

[Ray De Man]

NCVP I haven't done a serious install in a long time, but i've only ever used one inline fuse, between the battery and the amp.I'm curious as to why you have 2, but i couldn't say whether or not that would have any impact, but for the short amount of time it would take you to remove one of those fuses, i definately give it a go.

Hi mate, the only reason I used two fuses is that's how i've been tought how too. Its just an extra safety feature to protect your install. I had this setup done for ages and has never caused me any issues. Also it's sometimes easier to change fuse in boot (near amp) then it is with the main fuse by the battery.

[Ray De Man]

BIKY i use 2 for my amp setup, only because my power cable wasnt long enough to where i wanted to mount my amp haha so i used it as an extension, so i dont think that it would have an impact here?

is your amp overheating and shutting down by itself?? have you tried feeling its temperature? maybe even try replacing the 2nd cable that heats up too

I never use ready cut power wire that comes as a pack, they fit most cars but the larger cars there too short. I measure and take into account when installing it neatly under and around dash and door sils, I need to add a yard or two extra. Saying that using a fuse holder as an extension, I think that aint a bad idea ;-))

The amp if running for long periods is hot but not overly hot that you can't touch, it's just as hot as the stereo amp. At 5 minutes running, amp is still pretty much cold but still goes off! Replacing the cable may be a thing to do but I don't think anything is wrong with cable/s as 2nd cable from 2nd fuse stays cool.

[Ray De Man]

Holdenboy Sounds like a poor connection along the power / earth cabling.

Double check your connections at the battery, the fuse holders, sometimes the fuseholder itself is the cause, contacts can become loose and not make a good connection. Also check the power / earth connections at the amp and the earth connection to ground, make sure its tight and making good contact.

I have done that mate, all looks fine and tight! I did notice that the second fuse (which is a 60 amp fuse) is slightly discoloured gold in the zig zag pattern. Looks like it got hot or close to blowing but didn't. If you know what I mean? The thing that bugs me is why amp goes off but volt gauge (stringer) stays on and displays 8 volts, shouldn't it display 14+ volts with engine running and system off???

[holdenboy]

Yeah thats why i am leaning towards a connection problem, if the volt meter is displaying 8 volts with the car running youve got major problems.

I assume the battery still starts the car fine? Put your multimeter on the battery terminals while the stereo is on before the amp drops out, does it do the same? (drops to 8v)

With your multimeter, set it to "ohms" and take the covers off each end of the fuseholders to reveal the gold contacts. Put each probe on either side of the fuseholder and it should read 0 ohms. If it rises to anything major (0.01-0.1 is ok) then thats causing a bottleneck in the power cable.

[slipstream001]

sounds like a resistance problem...which is causing the cable to heat up...

[StoneX]

Old thread...

It's pretty simple to work out... Get a multimeter. When the fault occurs, stick the negative probe on bare metal of the chassis, stick the positive probe on the amp terminals and measure back along the power wire until you find the point it becomes 12-14v again. You can also measure from chassis to the ground point on your amp to see if there's any potential there. If you see voltage at the ground terminal, your ground connection is bad.

[sostok]

change ur fuses even if they look ok they can break away at ends slightly and cut down amperage

[Ray De Man]

Hi guys im still getting that problem. I thought I fixed issue as the second fuse connection wasn't too secure so replaced it. It aint been an issue untill today when playing music, I smelt this strange smell... Sub amp turned off, pulled over and saw that the fuse had blown (melted inside and metal part discoloured blue on one side) and plastic casing had hot bubble marks.
That was a goldplated Stringer fuse holder and a 60amp fuse.
What's going on??? Am I using the wrong fuse or is amp asking for more power? Is fuse restricting electrical flow too much?

Please help....

[StoneX]

What amp is it?

[Ray De Man]

StoneX - Amp is an Alpine MRP-1000 running at 1000 Watts RMS @ 2ohms. I used to use a JL Audio Q Max amp (1200 watt RMS) but it kept blowing so stuck with Alpine for now. I want to get the bottom of this problem as would like to run the full RMS into both Kicker L7's.

[Ray De Man]

[B][QUOTE=holdenboy;1494761]Yeah thats why i am leaning towards a connection problem, if the volt meter is displaying 8 volts with the car running youve got major problems.

I assume the battery still starts the car fine? Put your multimeter on the battery terminals while the stereo is on before the amp drops out, does it do the same? (drops to 8v)

With your multimeter, set it to "ohms" and take the covers off each end of the fuseholders to reveal the gold contacts. Put each probe on either side of the fuseholder and it should read 0 ohms. If it rises to anything major (0.01-0.1 is ok) then thats causing a bottleneck in the power cable.[/QUOTE

Battery is fine, holds charge well. If amp drops out battery still says 14-14.4 volts.

My multimeter didnt have a ohms setting but still did what you said but in volts setting instead. Ok if i put probe onto connection going into fuse holder it reads 14 volts but if placed on other end going to amp it reads 13.4 with system on but nothing playing. Ok so when system is playing it reads 13.8 volts into fuse but 11-13 into amp with engine running. At these volts fuse only lasts max 10 minutes play then blows. Im going through fuses like hot cakes. So my question is shall I upgrade from a 60 to maybe a 80-100 ANL fuse? What other options do I have?

[holdenboy]

So it reads 13.8v on the battery side of the fuse, but only 11-13 when the stereo is on?

Its either a fuse or fuseholder problem, Is it possible to bypass the fuse for a quick test?

You should be fine to put a 100A ANL fuse in there (considering it is 2AWG cable). Remember the fuse is there to protect the cable, not the amp.

[Ray De Man]

Thanks for your reply Holdenboy :-)

1. Yes that's correct 11-13v after fuse with stereo on.

2. I have replaced fuse holder already with a same type holder. No can't really try a quick test as have to strip half interior to get to amp screws as its on firewall. That said power wire is too short to reach amp. Can I get another piece of wire with bridging block and insulate it up just to try?

3. I will try get an 80 ANL fuse see how that goes... Yep totally understand fuse is only to protect cable and not amp. Amp has fuses onboard to protect it.

[holdenboy]

Try the 80-100A fuse first (easier).

Im not sure, but do you have two inline fuses in between the battery and the amp?

[Shaundy]

No dount you've already checked this but I thought I'd chuck in my two cents. I had a similar problem with my amp and I found that it was due to a single strand of wire from the power cable touching the signal wire. Fixed it with some proper terminals and I was back rattling the windows in no time.

[Ray De Man]

Fixed the problem finally!!!
Tried using a higher amp fuse but again blew! Looked at the new fuse holder and again that started to melt and the contact part was moving hence losing connection. I thought... Enough with this crap! So I ripped old 2 gauge out and fuse holder and replaced it with new stuff... Resoldered wires, new gold connectors. fuse holder (again) and what-do-you-know, it works and it stays on. To top it off there doesn't seem to be much resistance from fuse now.

If your wondering why two fuses... Well I used to have a power cap and it was reccomended that a second fuse was to be put in to protect wires. It's an old habbit too, running a second fuse in all my installs in the past as that's how it's been taught to me...

Now with all this extra power i'm now experiencing loads of power drain! This is never-ending! I either buy another Amp which is no point since the problem will still exist or add an extra battery somewhere, somehow??? Any thoughts on the matter?

[456adam]

You could try replacing the engine ground, battery ground and battery charge wire with heavier gauge cable.
Also known as the Big 3.
Will mean there is less resistance in your charging system so it should run my efficiently.

[holdenboy]

So you removed the entire run of 2awg cable and replaced it? Also replaced both fuseholders?

It's a simple fact that fuses add resistance, even if they are in top condition and have excellent connections. I really think you should get out of the habit of using two fuses. One within 30cm of the battery is all that's needed.
Anyway, good to you've solved the problem.