Holy Crud!!! More Under the hood electrical issues... PLZ HELP!! PICS!!

[snb778 5,000+ posts]

ohhhh God.... think it was a bad alt from the start then?? The batt is almost charged to 12.4now, and still rising...gonna let it charge over night... I dunno how low these Optima's can drop and be recharged..

But again.. if its the alt... when the car is OFF.. why would voltage drop when I hook up - bat. terminal?? That has nothing to do with the ALT at that point right??!!

Here is my previous thread a few months ago when I first got it

http://www.caraudio.com/forum/showthread.php?t=308290

 

[snb778 5,000+ posts]

That's not necessarily true. The alternator produces power by means of an electro magnetic field which is controlled by the regulator. Most cars run the positive to the fuse box from the bat, not the alt. So if you disconnect the positive from the bat that goes to the fuse box, your car is going to stall. Computer gets no power and your alternator regulator gets no power for the electro field. It works with the bat neg disconnected because the alt is grounded through the engine block to the chassis and all the wires in the fuse box have a ground to chassis.
Have you had a local shop load test your battery? Sounds like either your alt or bat are going bad. One reason I can see the voltage in the system dropping more when bat is connected is because the alt is going bad and the battery is drained. It's causing a big strain on the weakened alt when connected because it is trying to charge.

Start the car again and take a voltage measurement at the alternator, not the battery, with the bat neg disconnected. Take another reading from the alt with the engine rev'ing at least 1500RPM as well.

I can't even see my ALT - and + bolts... plus right now I am charging the batt to see if it even recharges... I dont wanna hook it up right now cause it will drop back to 11.9 if I do... Ill try doin that tomorrow and post results

also when I disconnect + power wire...the battery still continues to charge with the car off

Edit: New song I just heard by Young Joc "lookin boy" was pretty sweet

Right now I just gotta know why when I connect Chassic to Batt GND...voltage starts to go down....makes no sence at all

 

[snb778 5,000+ posts]

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1)front bat neg disconnected: 12.12V

2)front connected and the rear Pos. disconnected 11.9 (but only because the Bat - is now hooked up)

3)everything connected 11.9

I can't even see the -on my ALT to test it directly from the alt... best I can do is ALT+ and Bat. GND

These are all with the car on, and I didnt disconnect the batt in the back because its the same thing, whether is disconnected from one side or the other shouldnt matter...there is no power going to the back either way...get what Im sayin?

 

[jrwalte 10+ year member]

It'll probably give the same results (unless you have a bad engine to chassis ground, which is possible), but you could try placing the neg prong on the DMM or anywhere on the metal casing of the alt. They're both the negative of the alternator.

Also, did you try checking these voltages while rev'ing the engine to at least 1500RPM? Want to make sure you aren't having the low-RPM issue with your HO alt where it won't produce power below a certain internal RPM. Smaller pulleys resolve this issue.

You probably won't get an accurate reading until you charge all of your batteries off your trickle charger (sounds like you have one). Unless all of them are decently charged they could make your alt give a low 12s voltage reading while it is trying to charge them.

 

[jrwalte 10+ year member]

1)front bat neg disconnected: 12.12V

This is probably the current resting voltage of your rear bats

2)front connected and the rear Pos. disconnected 11.9 (but only because the Bat - is now hooked up)3)everything connected 11.9

Both of these are due to the near dead front battery. #3 is the same because your front battery is draining your rears trying to charge itself.

It definitely looks like your alt is giving no power to your electrical system. Even with a near dead bat, I don't think an HO alt would be below the mid 12s trying to charge it, not to mention the fact that your rear bats are also below their resting voltage (they should be 12.6+ with a healthy dry cell).

 

[lil_italy773 10+ year member]

to get that 12.5v he has to be chargeing 2 volts above that to get a resting 12.5v. same as the 16v batts have to be charging at 18.6-9v to have a 16.5v. so charging at 12.4 isnt gonna let him have a resting voltage any higher then high 11v.

im leaning towards the alt is going bad too. autozone has one of those wheel out deals that will check the starter and alt for u free. should go check them out.

 

[snb778 5,000+ posts]

are you f0cking kidding me... so this frickin ALT could be draining all 3 of my batts!!!!??

Hey guys just to let you all know, I just made a video of exactly what im testing...its about 5-6min. long...my cousin is going to upload it to youtube later tonight, then im going to post the link in a new thread... I don't have work until 6PM tomorrow, so if I don't know what is wrong for sure, I gotta bring it to a shop before I leave

 

[snb778 5,000+ posts]

to get that 12.5v he has to be chargeing 2 volts above that to get a resting 12.5v. same as the 16v batts have to be charging at 18.6-9v to have a 16.5v. so charging at 12.4 isnt gonna let him have a resting voltage any higher then high 11v.
im leaning towards the alt is going bad too. autozone has one of those wheel out deals that will check the starter and alt for u free. should go check them out.

yea I def. will early tomorrow...but as I said earlier in the post.. I went to merlin today and they had something that hooked up to my bat?? and its supposed to tell if the ALT is good... dunno if that sounds right or not but...they said the ALT was bad...just didnt have a clue why...said it could be the wiring and they didnt want to have anything to do with it.

 

[jrwalte 10+ year member]

are you f0cking kidding me... so this frickin ALT could be draining all 3 of my batts!!!!??

The alt isn't draining them. It just isn't charging them. Your electrical system is draining them...it appears as if they're 'running' your car.

I forgot to connect my regulator once after messing with my alt (which means it never put out any power) and I drove around for over 2 days until my battery finally drained and I started to stall. One quick look under the hood resolved it. Probably not as easy of a problem for you, but look to make sure your 3-prong connector on the alt (the regulator) isn't loose.

 

[bass-aholic 10+ year member]

yea I def. will early tomorrow...but as I said earlier in the post.. I went to merlin today and they had something that hooked up to my bat?? and its supposed to tell if the ALT is good... dunno if that sounds right or not but...they said the ALT was bad...just didnt have a clue why...said it could be the wiring and they didnt want to have anything to do with it.

lol, he probably saw the 1/0 snaked all around your engine compartment and said fvck that. //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

Anyways if the guy even said the alt was bad, and it really sounds like it is your alt than you know what to do....

 

[XHiFiX 10+ year member]

Start simplifying things first by just going with the alt and the single battery under the hood. Disconnect all the other wires going to your extra batts and whatever else. Redo your big 3 or check to see if they're grounded to the right places. Alternator + to Batt + / Engine Block to Chassis, Battery's negative to chassis. If you're good from there, start adding the other stuff to your electrical system and see where and what is causing the problem.

Since you got this stuff installed at the shop and it's not working like it's supposed to, shouldn't they be the one's to diagnose and fix what's wrong?

 

[Innovative:Cory 10+ year member]

Bad alt....

and you should never disconnect your battery leads while the vehicle is running.... in the years before fuel injection and the multiple computers used in today's more complex vehicles you could get away with this... doing this practice now will only result in more problems...

the primary battery of a vehicle only serves 2 primary purposes..... 1 to start the vehicle and 2 to filter excess ac voltage ripple....

it will provide power to the vehicle if the charging system is not able to keep up with the electrical demands of the vehicle...as in bad alternator or way too much current consumption...

but as everyone else has said...bad alternator and the batcaps in the back where helping keep the vehicle running....

as for why the optima battery is charging up on its own. the chemical reaction in a battery will slowly bring the charge up on its own over a small period of time..

 

[snb778 5,000+ posts]

ttt

yea, as i've said from the beginning....I thought this thing was bad the day I got it.. Light dimming problem got even WORSE once I got it installed....

The shop that initially isntalled everything isnt a car audio shop... I had to tell them where I wanted wires connected...therefore...they are not necessarily responsible because they did something that they really arent supposed to do.

Right now, I don't have an engine to chassis, I have a Bat-to chassis, and Bat-to *****. casing I believe..........if this could be an issue, someone please let me know.

 

[jrwalte 10+ year member]

You need an engine block to chassis...or at least to the bat neg (chassis is better). Your HO alt is probably grounding through a small OEM ground engine block wire or through your ****** ground, both probably with a high resistance. That would cause low voltages from your alt, though I don't know about as low as it is. But it would have contributed to quickly killing your alt (it was always having to work in over drive just to try and provide basic amperages because it's ground was weak).

 

[iamamp3pimp 5,000+ posts]

id think it wouldnt cause low voltage, just wouldnt allow much current through the wire...

right?