having volts drops any idea?

[desk0]

So here is the deal. I have this Honda Civic 2001 EX 2 years ago i bought an optima yellow top and then i started to install my sound system and HID lights.

at the beginning i only had installed my HU and one amp for 1 sub. and HID lights. just that, but when i turned the volumen up i had the typical dimming light. but after a few months of that i left the stereo on with the engine off but i left it for about 3-5 minutes playing music not too loud and then i tried to start the engine but the battery was already dead, so i had my local shop checked that for me because it was still a new battery they said the battery was fine and so my alternator. they just didn't know what the problem was.

and since that happen 3-5days later i had low volts. with the car off the battery read 11.85 volts and running 13.04 but when lights on and stereo playing 11.60volts. but then a few months ago the battery just died. the volts were 10.56volts and my neighbor help with the jumper and the car didn't want to start after a few minutes. then i left the car running and the car just turn itself off i couldn't start the car again.

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ok THEN, i bought a new battery the duralast gold at my local autozone. and i installed the battery and the car was running perfectly the car off read 12.48v and running 14.48v with lights on,a/c on, HU on. but now i have like 2 months with battery and i'm having the same problem, the volts went down, now it is reading 11.85v car off, 13.04v running, and 12.86v with lights on. and 11.55v or less playing music (depending of the bass of the song / with car still running)

aah but i gotta say i now have 2 amps. two Rockfords one t400-4 and a t1000-1bdcp and the dimming are way moore noticeable

here my questions.

1.When car running no matter if battery volts are too low and with HU off, isn't it supposed to keep running? as far as i know you can have a car running with no battery right?

2.can the problem be because of the amps and stock Alternator?

3.if the battery is reading low volts with only 2 months of use should i go to autozone and get it replaced or should i just replaced the alt for a bigger one?

any suggestions/comments please.

Honda Civic 2001 EX

HU Kenwood

Speakers amp Rockford Fosgate t400-4

Subwoofer amp Rockford Fosgate t1000-1

Subwoofer DC Audio 12" LVL 4

Car Alarm

HID Lights

and my dash lights were replaced now using LED lights

[14dbass]

I think will all that electrical you should get another bat.

[DTS909]

Do you have the big 3?

[MIKE-2U]

yes a vehicle car run off a dead battery theoretically. Example. All of my families farm tractors sit all year and we go pull start them . All there batteries are dead and don't hold charge. Now the reason i say theoretically is because based on your car and the computers to run and all that. But electrical wise if the circuit is completed it will run.

[desk0]

Do you have the big 3?

i wanted to do that i just replaced the grounds because they were almost like a speaker wire (12 or 16awg), but the alternator cable i didn't because people told me that it would be wothless because of the ELD.

[desk0]

I think will all that electrical you should get another bat.

and stock alternator can handle that?

[LCort101]

desk0

I hate to tell you this, but you have two issues you need to look into. You have a drainage problem when your car is off, and you have a low amperage problem when your car is on.

First, let's tackle the problem while your car is running. Most Parts places will test your alternator for free. Now it's possible that these guys want to sell you an alternator so if you have the ability to performa LOAD test, do it yourself. Otherwise take your car to two different places and see if they tell you the same thing. I think, from the info you have shared, that your alternator, or voltage regulator is starting to fail. A test from one of these places should help you narrow it down.

Now the drainage; I don't know your level of expertise, but there is an easy way to test for voltage drop using a multimeter. The meter needs to be able to handle a 10 Amp draw (most Flukes can do it). Make sure your key is off. Make sure your meter is set to an Amp setting and the leads are plugged in the appropriate place. Disconnect your negative terminal on your battery and place the meter in series between your battery and the negative terminal. Positive lead to the battery, negative lead to the cable that would normally connect to the negative post. anything below .02 amp draw is acceptable. anything above that will drain your battery .

Now the disclaimer: If you are not confident you can do this or if you don't know anything about electricity (electronics), Don't do it. Please leave it to a pro. I would hate for you to burn up your car and come back here blaming me.

Be safe man...

[desk0]

desk0

I hate to tell you this, but you have two issues you need to look into. You have a drainage problem when your car is off, and you have a low amperage problem when your car is on.

First, let's tackle the problem while your car is running. Most Parts places will test your alternator for free. Now it's possible that these guys want to sell you an alternator so if you have the ability to performa LOAD test, do it yourself. Otherwise take your car to two different places and see if they tell you the same thing. I think, from the info you have shared, that your alternator, or voltage regulator is starting to fail. A test from one of these places should help you narrow it down.

Now the drainage; I don't know your level of expertise, but there is an easy way to test for voltage drop using a multimeter. The meter needs to be able to handle a 10 Amp draw (most Flukes can do it). Make sure your key is off. Make sure your meter is set to an Amp setting and the leads are plugged in the appropriate place. Disconnect your negative terminal on your battery and place the meter in series between your battery and the negative terminal. Positive lead to the battery, negative lead to the cable that would normally connect to the negative post. anything below .02 amp draw is acceptable. anything above that will drain your battery .

Now the disclaimer: If you are not confident you can do this or if you don't know anything about electricity (electronics), Don't do it. Please leave it to a pro. I would hate for you to burn up your car and come back here blaming me.

Be safe man...

Thanks man, tomorrow morning i'm gonna do the drainage test and then take the car to do the load test.

BTW any idea of how much would it cost to fix the alt or voltage regulator?

[EricM9104]

Shouldn't be more than $150 for a new alt (OEM)

[Kranny]

Do you have the big 3?

i wanted to do that i just replaced the grounds because they were almost like a speaker wire (12 or 16awg), but the alternator cable i didn't because people told me that it would be wothless because of the ELD.

those people that told you that information are fucking stupid. "yeah, you have to change the grounds out but dont touch the one wire that powers the entire car that is practically 10 gauge". the big 3 consists of battery - to engine, battery - to frame (or strut tower if your car doesnt have a frame), and battery + to alternator +.

Edited January 11, 2012 by Kranny