Battery dieing?? maybe my sound system?

**gerald1** · 05-07-2006, 08:41 PM

O.K. so ive had my 1989 ae92 rolla for 3 months now i think. close to that. Ive had no problems with it at all up until now. Only mods i have are a tacho and now a sound system which was put in by Suss_slide on the weekend.

it consists of a head unit, 12 stacker in the back + sony amp + sony 6x9's

thats its. now a couple of days after it was all done, my battery went flat.

then it was fine for a few days. until today when it went flat again.

not sure what it is. the first time i thought it coulda just been a door not shut properly or something stupid like that but this time im sure its not cos ive been checking everything.

anyone got any ideas as to what it could be?

The first time i think it could have been because i played it while the car wasn't running for a couple of songs, but this second time has got me puzzled.

any explanations that i could follow up would be great.

thanks
gez

**Draven** · 05-07-2006, 08:42 PM

it doesn't sound like a crazy powerful amp, so I doubt your battery should be going flat like that. Who did the install? is it possible there's a small bridge draining your battery?

**Vios-GT_07** · 05-07-2006, 08:44 PM

last time i saw a battery drain just after a sound system install was because the AMP was stuffed.. it worked and everything, but wouldn't turn off and sucked up lots of juice that strained the alternator occassionally.. turn key off and it had lights and current through it.. then again, i've also seen head units that didn't have a "ignition" wire so it's connected directly to a power source and can turn on regardless of the key being off or not..

best bet is to work with a multi meter, and plug out the components one by one to determine if there is a power drain, and what is draining the power.

**suss_slide** · 05-07-2006, 08:46 PM

i put the head unit in, i checked for a acc cable and for a constant, then hooked them up. could it be that the earth has come lose? and maybe effed it up somehow?

**gerald1** · 05-07-2006, 08:47 PM

the amp is brand new. has a 2 year warranty on it so if anything is fucked with it i can get another. But i dont think it will be that. It has a little LED light and thats about all i can see when the car is off.

also the HU has a detachable face which i take off. Its suss_slides old one and he never had any trouble with it.

gez

**CLG** · 05-07-2006, 08:50 PM

Look for a current drain - you'll need a multimeter to do this

1: Set Mutlimeter to Amps
2: Remove Battery Negative from battery
3: place the multi meter positive probe on the negative cable
4: place the multimeter negative probe on the battery's negative terminal - you have now completed the circuit and your multimeter should read the current drain.
5: Current drain should be less than 0.05A, if it's more you have a current drain (at this stage make sure you have all lights off, doors closed, ignition off, ...)

Given your recent electrical additions, I'd suggest it wil either be one of three things:

1: Current drain - find the problem and fix it
2: Alternator not charging - charge rate should be 13.5-14.5V with the lights on (this loads the alternator - makes it work - you can measure this by running the car, turning the lights on and checking the voltage at the battery terminals)
3: Dead or dieing battery - ideally after running it should show a 12.5V+ voltage when the motor has stopped and hold that charge for the next cranking instance (ie overnight)!

Go forth and find out!

**WiLo** · 05-07-2006, 08:58 PM

Originally Posted by gerald1

It has a little LED light and thats about all i can see when the car is off.

that makes me think it isnt getting turned off properly, so either the remote wire wasnt connected to an appropriate source, or maybe there is a loose strand from the power cable that is touching the remote connection. but more then likely the remote wire itself IMO

**gerald1** · 05-07-2006, 08:58 PM

damn im gonna have to get a multimeter

thanks guys for the info

gez

**Bananaman** · 05-07-2006, 08:59 PM

You say that an LED is all you can see when the car is off? In other words, your amp is on all the time? Thats enough to drain a battery is it not.. I used to turn my amp on manually in my first car, and if i forgot the battery would go flat..

If this is the case, wire up the remote wire on the amp to the headunit, so that it doesn't turn on unless your headunit tells it to

**gerald1** · 05-07-2006, 09:26 PM

just checked what the LED was for. its a tiny little one just saying that the power surge protector thing is working/active.

When was trying to turn the car on and it didn't start, i was turning the key from ACC to ON, a weird sound was coming from the two stock speakers that are in the front of the car. We hooked these straight up to the HU not through the amp. I had never heard this sound before. should i check these with the amp meter aswell when the car is off ??

thanks for all the help so far

gerald

**Squid** · 06-07-2006, 02:51 PM

Listen to clint - he is on the right track, diagnose exactly what the problem is first before starting to pull out wires and blame the amp etc.

It could be the alternator or regulator.

I would:

1) check the current drain as per clint's instructions, making sure it is less than a couple of hundred milliamps. (if there is a signifcant drain, pull the fuse on the amp and check again)
2) check the voltage across the battery with the engine running you should get a healthy 13.5-14.5 V.
3) get someone to turn on the headlights, the voltage should drop, and then almost immediately recover.