toothlessracer

Hope you guys can help.
I have an Alpine 5 ch amp MRV 450
if I crank it up about 1/3 with the bass cranked up I loose sound. I think the amp turns off (amp runs all speakers) because it's not getting enough power. I turn volume down and about 5-10 secs latter I get the sound back.
I've benn thinking of getting a 1 farad cap to help this.

Also if I dont drive my car for 48 hrs or more next time I try to start it I have to jump starting. ( i dont know if it's a bad battery or the amp uses that much power) I've also thought about getting an OPTIMA battery.

What do your guys think? Does the amp use that much power or do i just have a really bad battery?

jesfuego

you can try a deep cell battery or you can try a 1/2 farad capacitor on your amp. First I would check your battery to see if it is holding its charge then try an alternative.

I have 3 amps and have a 1 farad capacitor I dont have any battery problems at all.

dczoner

iTrader: (1)

It sounds like you actually have a bad system hookup. Everything you describe could be due to some faulty wiring - wether its the wiring itself or the way it was hooked up. The big question, did you install the system yourself? If not, then I would take it back to your shop. Absolutely no system with that little power (not to belittle your amp but its not like its running a SPL race) ought to be giving you such a hard time.

If you did the system yourself, I would say step number 1 is to double and triple check your grounds. Also, while the car is off, check your wiring with a voltmeter. You should be @ 0 but if there's something causing a "draw" on your system it'll show when everything is off (mind you it could be tiny). . .

Beyond that, I would also check the grommit point between your amp and battery, to make sure you're not bleeding power out through your firewall. Check your grounding kit to make sure all those connections are still in place.

When everything is said and done, you should have identified a problem somewhere along the line. If you amp plays properly and is generating a quality sound, you should be fine in that respect.

However, after your day of diagnosing, it'll probably be worth the while to get a new battery too (doesn't need to be anything special, just a std. replacement from sears).

Oh, jesfuego does have a great point with the cap - a cap is designed to allow instantaneous delivery of a significant amount of amperage before it draws off your battery.

peanuthead

Check your grounding point and invest in an optima yellow top . . . deep cycle gell cell is the way to go even if you're not running a system.

A capacitor is also a good idea

jreiter

iTrader: (6)

I would agree with dczoner on this one. Based on the symptoms you are describing, there must be a problem with your wiring or perhaps even a faulty amplifier. If it's draining your battery while it's off, then I'd say you definitely have a power cable slightly grounded out somewhere. The accidental grounding point could be small enough and slight enough that it's not drawing enough power to blow your fuse in your main power wire. (You did use a fuse on your power wire, right?)

A bad amp could cause the same thing, though. If the amp has some faulty circuitry in it, it could be grounded out internally somewhere. This would cause the same thing (constant, slow power draw), and would definitely cause the amp to shut itself down when you try to crank up the output.

So do like dczoner suggested and double check all your wiring. If possible, swap another amp in place and see if it works fine. If so, your amp might be bad.

toothlessracer

thanks guys,

i had the system installed by a shop but they take forever to do anything. I'm going to do a volt check if it's ok i'l switch amps with the one in the Eclipse.

If both come back ok. I'll get an optima battery.

bastard

It must be something in your wiring or your amp's defective, and if your battery is dying in 2 days, an Optima won't fix it.

Have your shop take a look.

jreiter

iTrader: (6)

Exactly. If there is something draining the current battery, it'll drain the Optima, too.

toothlessracer

last night i ran the amp at 3/4 9f volume (normally anything past 1/3 and sound stops from the amp) for about 1/2 hr didn't have a single issue.
Then I decided to go for a drive figure with the head lights on and foglights it would put more of a train on the power supply. About 3 blocks from the house i notice a burning smell. Thought the smell was coming from inside the car so i turned of the stereo and looked around for smoke. Didn't see anything so i kept driving to the house.
Checked the amp, it was hot but not excesively. Checked the wires around the amp they looked good checked under the hood everyhting was fine. I Ran the stereo for another few mintues still @ 3/4 of the volume. Again no issues.

Later today I'll do the volt test on the amp and foglights either one could have a ground causing the battery to die.

At this point I figure I don't need a cap since the amp ran fine @ 3/4 of the vol for 1/2 hr. I don't need it that loud for normal listening. However I do not want my battery to keep dying so I need to figure what's going there.

thanks for your help

toothlessracer

Just remember something I forgot to mention earlier. On couple of occations my driver side tweeter has had no sound. I think a wire is loose.

Here's my question if a speaker wire is loose and grounding out, could this be the cause for the battery being dead (would it matter if the speaker is grouding out whilte the stereo is off).

Today when i do the volt test in about 1- 1 1/2 hr if I turn on the system and I connect the lead to each channel, the reading on each channel should be constant unless i have a short then there sould be a fluctuation right? (This way I can atleast isolate it to which channel is being grouded if it's the speaker wire at fault and not the main power wire. Dont worry the main power and ground are the first things I'm going to check.

toothlessracer

I did a voltage test on the amp. I'm getting pretty good power and consistant.

While the car is off i get 12.8V, drops to 12.4 with system on.
While the car is on I get 14.6V, drops to 14.1 with system on.
the drops occur when the bass hits.

However i did find that the remote wire to the amp gets about 2.1V while the car and stereo are off. This is the reason the battery keeps dying.

Another thing I found is that every channel has different voltage running through there aren't two alike not even close.

Still don't know what is causing the amp to loose sound (power) at high volume, but I know now that it's not all the time. I ran the stereo today @ 3/4 volume again, this time for about 3 minutes only no problem (i've experience the amp loosing power @ about 1/3 the volume in the past).

toothlessracer

I'll probably switch the amp from my Eclipse or MB into the Z tomorrow or Thursday (all the amps are Alpine). If I still get a Voltage reading on the remote wire I know it's faulty wiring from the head unit or EQ depending on how the shop wired the system. If I dont then the amp currently in the Z must be grounding out.

jreiter

iTrader: (6)

No, a shorted speaker wire won't drain your battery, but it can cause problems for your amp while the amp is running. (It won't hurt anything while the amp is powered off, though.)

It's really sounding like a bad amp to me. If you can be sure that your power wire going to the amp is not grounded out anywhere, then I'm betting it's grounding out inside the amp. This would explain both your battery dying, and your amp cut-out problems. (And potentially even your tweeter problem.)

On another note, you mentioned fog lights, which on a 350Z had to have been a custom install, correct? Be sure to verify the power wire to those, too. A bad fog light power wire would explain your battery dying, but not the amplifier problems.

In the meantime, as a test you can disconnect the power wire from your amp, then let your car sit for a couple of days. This will eliminate the power wire and the amp as culprits. (I'm still voting on it being a bad amp, though.)

toothlessracer

i checked the wiring on the foglights and it's fine. I'll try and switch out the amp on the Z for one in another car, if there is no power being drawn on the remote wire then I know it's the amp. If it still draws power I know it's the wiring between the Head Unit and EQ.

Last two days I've blasted the music without the problem of the amp shutting down. An easy way to fix this is to run an interupter switch on the remote wire. (it would have to really small and discreet ($3 and about 1hr of my time).

specialp

this is prob a short problem. if the wire going to the amp is straight from the battery then I would test resistance from the positive lead to the ground with the wire disconnected from the battery. if you get a reading then you know your positive line is grounding out somewhere.

toothlessracer

Yet another twist. I was goint to swap amps with the one in the Eclipse(6 yr old system, no issues) On that amp I also get a reading on the remote wire with the car off and system off. Then I checked the one in the MB (6 month old) also got a reading on the remote wire.
The best part is that the reading on the Eclipse is 30V according to my meter(how can this be since the power source is 12v), the one on the MB 18V what is going on. Neither the Eclipse or MB have ever given me trouble.

I turned on the system on the Z after about 10 min sound stopped for about 5 sec then came back on. I did notice that while there was no sound the protection light came on.

I've got a guy from Alpine helping me trouble shoot. He thinks the Ohm load may be too much for the amp I've got to get some readings for him by tomorrow see if he can figure this out.

toothlessracer

specialp,

Let me get this straight, I disconnect the power wire from the battery then I connect one lead to the power wire and one to the ground on the amp or any ground? If I get any kind of reading then it's the power wire grounding out prob at the firewall

jreiter

iTrader: (6)

You definitely should not just put in an interrupt switch for the power wire. That would be addressing the symptom, not the problem. Gotta figure out the root cause.

I don't believe it's too low of an impedence load on your amp. That could explain the amp cutting out, but not the battery drain while the car is off.

Your voltage measurements on the remote wire were probably in millivolts, not volts. Most digital voltmeters will auto-switch the decimal position on the display as needed. That being the case, 18 or 30 mV isn't unusual for most headunits that I'm aware of. Ideally you'd have zero volts on the remote wire when the headunit is off, but a few millivolts won't hurt. Yes, it will draw current from your battery, but it's tiny and shouldn't cause a problem. It definitely shouldn't drain your battery in just a couple of days. (A few months, *maybe*.)

It sounds like you have access to another amp. Just hook that darn thing up and test with that. If you switch amps, and all the problems go away, there you go. Bad amp.

If you want to do what specialp mentioned, that's not a bad idea. Disconnect your power wire from the car battery and from the amp so the wire is not connected to anything on either side. Then, set your multimeter to measure resistance. (ohms) If you connect one lead of the meter to the power wire and the other meter lead to the car chassis (ground), you should show get no reading (infinite resistance), meaning that the wire is not touching the car chassis anywhere at all. If you do show a numeric reading of some sort, that means your power wire is touching ground somewhere. That's bad. If the power wire ends up being fine, then that really points to the amp being bad.

I already think it's the amp, though. Let me break down my logic using the different possibilities of your situation:

1) Slightly grounded power wire: Could explain the battery draining, but not your amp cutting out. Usually caused by the wire insulation rubbing off and contacting metal, or perhaps by it being accidentally cut during installation, and thus contacting metal where the cut is.

2) Too much load on the amp: Could explain the amp cutting out, but not the battery drain. Too much load is caused by running speakers that have a lower impedence than the amp is rated for. (Or it could be a faulty speaker, but unlikely.) When you amp is powered off, though, it doesn't matter what sort of impendence you have across the speaker terminals.

3) Bad amp: Could explain the amp cutting out and could explain the battery drain. The internal amp circuitry could be messed up, causing a small short in the power circuits, making them constantly draw power even when the amp is off. This messed up circuitry could also cause the amp to cut out as power requirements increase (when you turn up the volume.)

4) Bad head unit: Same as a bad amp. It could have messed up circuitry which is constantly drawing power even when off. Remember, though, that a headunit typically does draw a small amount of power all the time so it can remember your settings, clock, etc. This would explain the battery drain, but not the amp cutting out.

5) Bad signal processing equipment, such as an external EQ: Could explain battery drain, but not amp cutting out.

So you can see that everything points to #3 unless there's some other info you can give us.

toothlessracer

I'm really hoping it's not the amp. I hate to shell out $350 -$500 for another amp.
Here's another situation.

Power wire is grouding out, thats why the battery keeps dying. The SUB I have is DVC 2 Ohm x 2. Wired for a 1 Ohm load. I lost the manual so I dont remember if the amp is stable @1 Ohm. This would explain the reson the amp is cutting out @ high vol.

If this is the case I just need a new power wire and rewire the SUB for a 2 Ohm load.

I hope this is the case, it would be alot cheaper.

jreiter

iTrader: (6)

Alpine posts their manuals in PDF format on their website. I believe your amp is this one:

http://iweb.alpine-usa.com/html/asb/...rv-f450_om.pdf

This amp does not handle 1 ohm. It will do 2 ohm unbridged, or 4 ohms bridged. That would definitely explain the amp cutting out. Rewire your sub to be 4 ohms and run it for a while. Hopefully this will fix the cutting out.

Then you're only left with the battery drain problem.