Any ELECTRICAL SYSTEM experts here??

[gmrulz4u]

Car: 1989 Olds Cutlass Supreme 2.8L

 

Battery: Optima Red Top(8 months old)

 

Alternator: Re-Built High-ouput 140amp(8 months old)

 

Ground and Power Wire gauge changed to thicker core.

 

Problem: With engine running, brake depressed, and heat on full, battery only showing 11.5 volts! This is WITHOUT my $3000 stereo or fog lights turned on(which makes it even worse!)

 

Before being quick to blame it on the alternator, I will let you know something that I find very strange is that EVERYTHING seems to take WAY MORE power(voltage/amps) than it's supposed to.

 

For example, with my car in park(idling), the voltage shows 13.4 volts, if all I do is put my driver side power window UP, the voltage will drop to about 11.6 volts!!! I can't imagine a power window taking almost a full 2 volts of electricity!!! It's not just my power windows, it's anything such as brake pedal, fog lights, heater/AC etc...

 

So, when any and every electrical component is draining the battery more than it's supposed to, what is the usual cause?? Bad connections? Alt? Battery? Voltage Regulator?......

 

THANKS:)!!

PS, I know I've posted these typs of problems before, but I was never this specific...

[Brian P]

Id say get an energizer battery

[ismellrealbad]

well im no electrical expert but based on experience with what your describing i think you battery is about to take a shit. If it is a slowly dying battery i would replace it soon before it makes your nice alt crap out also. A power window will consume that much when its being forced ex:continuing to hold the button down after its already down.

my battery is about to crap out because i constantly sit in my car to listen to tunes for an hour almost to the point where its dead then start the car to charge it again. this drain/charge pattern is terrible and my battery is now almost dead. it holds just enough charge to start the car again and from theron the alt is providing the rest of the power the car needs to do anything else. if i turn the heat on, press the brake, turns the lights on, any visible light will dimm and the engine will come very close to stalling. im not saying its definatley that but my opinion is that

[crc]

When you're talking electric loads it's more useful to talk about Current than Voltage Drops (ok, so both do go together). You can drive yourself crazy trying to determine a problem by voltage drop alone, which can spike up and down incredibly often in a car.

 

Few months ago I had to track down a current leak that was draining my battery when my car was parked. Every two months my battery would be completely dead after a long, cold night. That would be my grouchy days. I had to pretty much measure, poke, pull and look at all the circuits in my 1990 Cutty international to track the leak. Meanwhile I found that even the 4 interior lights (two rear dome lights and the courtesy lights under the rear view mirror) drew as much as 3 Amps alone. Hitting the door locks made a temporary current spike of upto 12 amps. On the scale of electric loads, the starter is the king (it temporarly draws massive amount of current), while the smaller electronics are at the bottom.

 

From the numbers you posted it doesn't look immediately like you have a problem. Are you noticing anything like headlights dimming when you hit the door locks, or pull down the windows? A massive voltage drop sometimes is a sign of wires being of wrong or insificient gauge. But hold on! It could also be because of two dozen other things so keep that in mind. Don't go off buying huge wires because that introduces other problems.

 

I would say park your car, turn it off. Stick an ammeter in there and observe first of all if there's any current leaks with everything (and i mean everything) off. For the Cutty this should read in the low milliamps at the heighest. This is your ECM, your headunit and other "always-live" circuits using a tiny bit of your battery to hold stored settings.

Next, I would switch on various things to see how much they draw from the battery, which is almost the same they would draw from the alternator when your car is running (excluding some electro/mechanical things like heater/AC).

 

When your car is running your battery is now a load rather than a source (atleast that what's supposed to happen!) Understanding this is very important. This is one of the major reasons for the alternator output being higher than battery voltage. Anyway, i your case you have a big-ass alternator and a massively rugged battery so technically you should be able to supply the electrical needs of a small midwestern town.

 

j/king..

 

You should be fine, man.. The HVAC system in the cutty is a power hungry beast, both mechnically and electrically. The blower fan alone can explain the voltage drop you are experiencing, although i'm a bit skeptical about rolling up the windows. I'm not sure how you are measuring the voltages and/or currents, at what point, etc...

[89BuickRegalGS]

I have a electrical question kinda concerning this:

 

The other day with mny stereo on low, so almost no bass coming forom my subs, and the car idleing in park, i noticed that if I reved my engine slightly, the headlights would brighten... is this normal?

[gpse3200]

Car: 1989 Olds Cutlass Supreme 2.8L

 

Battery: Optima Red Top(8 months old)

 

Alternator: Re-Built High-ouput 140amp(8 months old)

 

Ground and Power Wire gauge changed to thicker core.

 

Problem: With engine running, brake depressed, and heat on full, battery only showing 11.5 volts! This is WITHOUT my $3000 stereo or fog lights turned on(which makes it even worse!)

 

Before being quick to blame it on the alternator, I will let you know something that I find very strange is that EVERYTHING seems to take WAY MORE power(voltage/amps) than it's supposed to.

 

For example, with my car in park(idling), the voltage shows 13.4 volts, if all I do is put my driver side power window UP, the voltage will drop to about 11.6 volts!!! I can't imagine a power window taking almost a full 2 volts of electricity!!! It's not just my power windows, it's anything such as brake pedal, fog lights, heater/AC etc...

 

So, when any and every electrical component is draining the battery more than it's supposed to, what is the usual cause?? Bad connections? Alt? Battery? Voltage Regulator?......

 

THANKS:)!!

PS, I know I've posted these typs of problems before, but I was never this specific...

 

One thing is that the alternator compensates for the temperature around it(engine compartment) as not to overcharge the battery so it's natural for the voltage to be lower when you are say stuck in traffic as opposed to in the morning just leaving. If you car starts and starts in a normal time/speed then I'd say the battery is ok. But yeah a motor as big as the power window motor will take juice, the brake lights, A/C, Powerseats, etc all have a large power consumption. The alternator will let you know when its headed south, by the red light on the dash. Lets put it this way if you are cruising and the gauge doesn't eventually reach past the half way mark, if it stays halfway and below at cruise thats an indication.

[Whiskey River]

You should also have your alt load tested. I have found out that High Current alts tend to put out less current at idle than the factory alts. Does all this happen with the car running at 2500 rpm? If not, then your alt isn't putting out very much current at idle. Something to think about.

[rockfangd]

my cutlass does exactly the same thing ugh lol :willynilly:

[cutlsp]

Welcome to the typical W body charging.

 

AND HOLY 3.6 YEAR OLD POST!

i'm going to be working on that soon enough i'll do a nice write up on it too.

[slick]

Did you upgrade all power wires, and all ground wires, or just like one or two?