Memphis ST1500D Turning Off

[jrwalte 10+ year member]

I just installed a Memphis ST1500D and I'm trying to figure out why the amp is [rarely] shutting down for a split second and then turning back on at high volumes.

I have a single RD 15" Elite DVC 4 ohm rated for 1000 RMS. It is wired in series and I have it connected to the outer negative and positive connectors of the amp. Should I just have this connected to the neg and pos on one side of the amp or does it not matter? It shouldn't matter if the sub is connected in reverse polarity right? I had a shop install the sub since the box was free with sub and its possible they wired it backwards.

I'm running 0 guage on my stock alternator of 80 amp and stock battery (I know these need upgraded). My current alt can handle the amp at decent listening volume but when I turn it up my volt meter drops to the battery on hard hits and continuous bass.

At first I thought it was an over heating issue. After I pulled over the first time the amp was pretty hot. But I don't see my one 15" overheating a 1500 RMS Memphis. But now I don't think it isn't a heating issue. This morning while driving to work it was fine the whole trip. Right before pulling into work I turned a heavy bass song way up and almost immediately the amp cut off twice for a second about 5 seconds apart. When I turned the volume down a little it didn't shut off anymore. Then no more than a minute later I parked and touched the amp. It was cold - not even luke warm.

Is it possible my amp is turning off because my alt cannot provide the power the amp needs during a heavy hit?

Also, another question while on this subject:

If I can only get one yellow-top etc battery right now, where should I place it? Under my hood or leave my stock under the hood and place the yellow in the trunk? Or just hold off on the battery to apply the money towards a ~150 Amp alt?

Click to read more...

 

[ThatChevyGuy 5,000+ posts]

Place the yellow in the trunk and that should help. You can burn that amp up with that voltage dropping.

 

[craigzter 10+ year member]

Place the yellow in the a trunk and that should help. You can burn that amp up with that voltage dropping.

agreed.

 

[jrwalte 10+ year member]

Voltage drop can hurt the amp?? So you're saying if the voltage drops below around 12 it can damaged the amp? I assume dropping to the battery around 12 volts wouldn't hurt the amp.

That means it probably is shutting off because it's trying to draw too much power and my crap stock battery can't handle the sudden draw and it drops below 12 volts, but the drop may be so 'short' that it doesn't display on the volt meter?

 

[darkist240sx 10+ year member]

yeah its cutting out at high volume becasue its pulling more current that your electrical can give. Get something in the trunk to help or keep the volume a little lower. you might blow ur amp if u dont.

 

[req 5,000+ posts]

another battery will not cure voltage drop. the only thing to help your electrical system while driving is a new alternator.

and set your gains properly. i bet you just turned them to where you think they are good at.

http://www.caraudio.com/forum/showthread.php?t=63933

 

[J31Rob 5,000+ posts]

another battery will not cure voltage drop. the only thing to help your electrical system while driving is a new alternator.
and set your gains properly. i bet you just turned them to where you think they are good at.

http://www.caraudio.com/forum/showthread.php?t=63933

//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif yes.

 

[jrwalte 10+ year member]

another battery will not cure voltage drop. the only thing to help your electrical system while driving is a new alternator.

That's understood. Depending on the cost of a ~150 alt I don't know if i can do that now or not. Waiting on a quote for a couple. But if i have another battery in the trunk and the volts don't drop below 12 will that still damage the amp?

 

[jrwalte 10+ year member]

The amp is now turning off at even low volume. Could that still be a voltage issue or something else as well? I'll usually see the volt meter on the 800PRS drop to 13.2 or 12.7 right when it happens.

I'm thinking it may be happening more now and at low volume because I'm having to turn the AC on. The warm weather also makes my car turn its radiator fan on. Toyota did a stupid electric motor setup that turns on when needed instead of a belt. I'm sure that motor has a big spike when it first cranks up and it constantly turns on and off.

I've had my music paused and I've seen my voltage drop in the 12s with no music playing when that fan motor kicks on. This electrical system sucks //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif I think I'm going to skip the battery in the trunk and go straight for the HO alt first. I don't know when my current alt could ever even charge the second battery.

 

[thevic24 5,000+ posts]

check your ground for the amp, make shure everythig is good and tight and that the grounding point is free of any paint.

 

[jrwalte 10+ year member]

check your ground for the amp, make shure everythig is good and tight and that the grounding point is free of any paint.

I used a dremel to sand the spot and used a streetwires grounding block. I have it in the spare wheel well. The Eclipse 4 channel 175x2 and my old PG Ryval 800RMS sub haven't had issues on this grounding spot with turning off.

 

[DaGh0st 5,000+ posts]

another battery will not cure voltage drop. the only thing to help your electrical system while driving is a new alternator.
and set your gains properly. i bet you just turned them to where you think they are good at.

http://www.caraudio.com/forum/showthread.php?t=63933

Agreed. Big 3 would be a + when getting the alt aswell.

 

[jrwalte 10+ year member]

Agreed. Big 3 would be a + when getting the alt aswell.

First thing I did with 0 guage when I installed my amps in this car //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif All I need to do is find an alt and drop it in.