bad alternator?

[peter]

As some may know I experienced problems with my car about a month ago. If not its all herehttp://www.sl-i.net/FORUM/viewtopic.php?f=3&t=19027
I ended up not doing anything and the problem didnt persist. But the last few days some of the same has been happening, stereo shutting down, lights getting real dim, that kinda stuff. I was trying to be cautious and not do so much to overload my car and cause problems. But this morning when I went to start my car, it wouldnt. I assume its a bad alternator and battery.
I grabbed a multimeter too see what I could find out.
Car off 12.2 volts
Car on, all accessory's off started at 13.8 volts and was constantly dropping
Car on, all accessory's on started at 11.9 volts and was constantly dropping

What do you guys think? Bad alternator and battery? :-?

[LiCelsior]

put if off and have autozone test it.

[Legacy89]

Seems to me that you either have a short or a bad alternator.
What voltage are you getting directly from the alternator?

[peter]

I don't have an autozone around here. Does oreillys test them?
And I didn't check directly from the alternator

[LiCelsior]

um im not sure if o'reillys checks them.

[peter]

So I went ahead and got a new alternator. I'll be installing it on wedensday. Now I'm sure my battery is also bad. Should I spend the extra money and get an Optima red top? I do have an upgraded stereo with a new head unit, new speakers all around, and a 12 inch sub and amp. And in the near future I may get some lighting upgrades. Would that be enough to justify spending the extra money?

[Legacy89]

When a battery first gets empty it loses some of its capacity. Enersys Odyssey, Optima or Kinetik. They are all good, Just get the one with about the same amperage of your alternator. Say its a 60A alternator get 60/65AH battery.

[peter]

When a battery first gets empty it loses some of its capacity. Enersys Odyssey, Optima or Kinetik. They are all good, Just get the one with about the same amperage of your alternator. Say its a 60A alternator get 60/65AH battery.
Well I can't find any information like that for optima batteries. All I cab find out is that I need a group 35 battery

[LiCelsior]

damn too bad, autozone gold batterys are pretty good lol.

[Legacy89]

What is the Amp output on the new alternator?

[chuckthefuk]

Your alternator should never drop below 12v w/ or w/o accessories.

Many people neglect the battery after they swap their alternator thinking that the alternator is the fix.

If your alternator was working overtime to charge your battery, and your battery was constantly being drained by your sound system or day to day use. This eventually causes your alternator to die/produce lower Volts/Amps. This in turn made your alternator run even harder to charge your battery, and this caused the battery to be "strained" by constant charge/discharge.

Go with a Optima and never look back.. A few people will argue but for what its worth isn't peace of mind a good thing to have when your enjoying your car?

-Chuck

[peter]

Well that's a great answer right there. I thought that's what was happening. New alternator and a red top going in tomorrow

[iampetro]

sooo?

yo and i are having the EXACT same problems, did your battery fix it? how hard was the alt install?

UPDATE PLEASE :)

[peter]

New alternaor and battery did the trick. And the install wasn't hard. Just takes time to figure out how it all works

[chuckthefuk]

Mmmmmmm mega cold cranking amps :-D
-Chuck

[peter]

My optima red top has more cca then my old one had ca. One thing that does dissapoint though after all this is that my dash lights will still dim when using other electrical accessories. And idk what to do about that

[chuckthefuk]

install a capacitor between your battery and amplifiers and nothing should go dim.
_Chuck

[peter]

Only thing is, they don't dim with my sub, unless I turn the volume up really high and adjust the sub output on the deck to max. What I'm talking about is rolling up windows or even just hitting the brake. A cap wouldn't help that, would it?

[chuckthefuk]

..unless I turn the volume up really high and adjust the sub output on the deck to max.

Thats where a cap would help. Your tweaking your system for high output, lots or RMS and wattage so your battery is being drained at an alarming rate. The cap will store the power and discharge when the amps draw more then your battery can handle. While at the same time the alt is charging the battery and not being drained since the cap is handling the load.


What I'm talking about is rolling up windows or even just hitting the brake. A cap wouldn't help that, would it?

You cant escape this... even with my new alternator and red top the lights dim a bit when I use the window regulators or any major relay like the turn singles as well as the brake.

A high-output alt will not solve this since there is sufficent power/charge going to all your accessories.

There may be a solution but I have not found it yet :smt017

-Chuck

[peter]

I kinda figured that was the case. I wasn't going to worry too much about it. I assumed there wasn't much I could do to fix it after I got a new battery and alt. I'll just live with it

[mike-tracy]

I experienced some of the problems you had, and was able to troubleshoot down to the alternator, which I replaced. I still had the dimming with standard stuff on (headlights, GPS, radar). What I did was go through the engine bay and take all ground wires & sand the connectors & part they touch on the body. Then I sprayed it with dielectric grease to seal em in. Also sanded the car's positive cable and it's two connectors.

The difference was night and day. My engine idles smoother, starts quicker, lights barely dim compared to before, etc. I can see why people have success with grounding kits considering how degraded my grounds were.

[98outbackpdx]

just an fyi if that happens again les schwab, and nelson tire factory will check your charging system for free, my car stalled on me because of a bad battery, then the alternator went after it was checked out fine. also if you didn't want to spend the $130 @orileys for an alternator the Subaru dealership in town sold me a reman subaru one for $79, although it only has a 12mo 12k mile warranty but big chunk of change difference.