Thread: Do I really need a HO Alternator?

Your battery acts like a reservoir for your charging system. After cranking mucho amps into your starter to get your engine started it would normally settle back and let the alternator take over supplying power to the system. At the same time your alternator would be recharging your battery for the next time it's needed to crank up again.

Your battery is rated on how many times it can do this time after time before falling to a point where it cannot hold a charge as well as it did before, also known as your battery service life.

When the electrical system needs a little more omph that the alternator can't handle then the battery will provide the little extra juice needed to keep things running smoothly. But if your alternator is consistantly not providing enough for your electrical needs then the battery starts to slowly get depleted since the alternator isn't providing enough power to supply the system and recharge your battery. In other words, dimming lights.

I think that is what happened to your alternator, it wasn't providing enough juice to keep everything powered up and happy and so your battery had to provide that extra little omph.

At first, since your battery was still new, it had enough reserve to keep everything happy. Eventually, this depleted your battery to the point that it actually decreased the service life of your battery. Basically you went from 800 cold cranking amps to only 300.

When you got a new alternator, you should have replaced the battery as well since even if your alternator could supply the entire system it still could not fully recharge your depleted battery. When you get a new alternator think about replacing your battery as well.

I think at least a 190 amp alternator would be the very minimum I would look at. Depending on your driving habits, short trips, heaters/AC use, etc you might need something much bigger.

Also being an Optima battery, you might try using a trickle charger to see if it will charge back up completely but I doubt it since it never ever really got completly recharged in the first place. A new battery is basically moot though if you don't get an HO alternator for your system soon.

Hope this helps... :music:

Thanks a lot for all the replies. Just to answer a few things. My driving habits did change a little while ago (like a month and a half before this started happening). I drive a lot more at night and long distances, such as 85ish miles round trip. (it is on the freeway though so I would have thought it was charging my battery enough) and It's 3 days a week. I do have my stereo, lights and heater on as well though. So that very well could be a problem, didn't even realize that.

Also with the battery thing, that is what I suspected to be the problem. See before I made all these changes, checker was the place that told me about my battery being at 300 cold cranking amps. Also when my equipment was all in use, my voltage dropped down below 12v so he said that the alternator was going out. He also said the battery was fine, and once you get a new alternator it will charge the battery back up and it should be ok.

So when I got the new alternator (thinking the battery was at 300 cold cranking amps or less by now) I put a battery charger on it. It was only on for less than 10 mins and it said it was fully charged. Now I was confused why that'd be if it was so low earlier, I was afraid the battery was bad. I then took it to a battery store to see if it was dead or not (rather than back to checker or autozone). He tested the battery and he said it's just fine, it was putting out over 900 cold cranking amps, and he said he didn't know what the checker guy was talking about. That is when they also tested my old alternator and everything saying it was also just fine. (reading showed over 14v)

I think all of you guys are correct though. With my driving habits changing, and now over a year my battery just isn't able to keep up the slack for the alternator anymore, and the capacitor may even be causing more of a problem now than helping. I am going to get a highoutput alternator for sure, (and probably a battery as well) but before I do that (since I can't afford them now anyway) I am going to go to the car audio place that installed everything and have them unhook the capacitor and see if it makes any change at all.

Thanks again for all your help.

-Cody

New alternator and no change? Check your fuses. All of them. Make sure they are in the right spots and not burnt out. There is no reason why a new alternator is not recharging your battery or supplying enough electricity at minimal draw. Check your fuses.

Originally Posted by Dercas

My setup:
Deck - Pioneer Premier DEH-P400UB
Subs -Two Pioneer Premier 12" Champion Series PRO Subwoofers with 3000 Watts Max. Power Wired at 4ohms 600watt RMS (each)
I can't exactly remember the mids and highs, but I know I have two pioneer premier 6x9's and two 5 1/4" components. (can't remember the wattage exactly)

Pioneer 4-Channel Power Amplifier with 600 Watts Max. Power (hooked to mids and highs)
Pioneer Premier™ PRS-Series Class-D Mono Amplifier with 1200 Watts Max Power Two of these one to each sub
Tsunami 5 Farad Capacitor
Planet Audio Two channel line driver (8v output)

Here is my problem: (lights dimming now)
I have a 95' Ford Taurus 3.0L V6, comes stock with a 130 amp alternator. I also upgraded my battery when I got my system to the Optima red top battery.
When I got my system everything was fine, I've had it for almost a year. It is setup to where I put the volume at 48-50ish is perfect. When I have it there my lights dimmed a little bit, but I'd have to really look for it to notice. (which wasn't a problem)

However the past month or two my lights have been dimming a lot. They are even starting to dim when my volume is at 35. (and they dim more at volume 35 now than they did when my volume was at 48 or 50 a few months ago).

So I had some things tested, I thought it was finally my alternator going out (since it's still the stock one). Autozone had tested everything didn't say anything was wrong, then checker tested stuff said the battery was putting out 300ish cold cranking amps when it's supposed to be putting out 800 minium. They said the battery it self was fine but the alternator wasn't charging it like it should. Which after driving it I noticed the lights dimming more and more and having to lower my volume down to like 25-30 to avoid dimming. So I figured he was correct, and my alternator is slowly going out and my battery is taking up the slack.

Now to make this long story a bit shorter:

I replaced the alternator (after market 130amp (highest I could get))- No change
Had a battery store test my battery and alternator (they were both fine (even my old alternator))
I had the audio store that installed my system check the cap, everything seems to be fine, displays 14.5v, around 12ish when the volumes all the way up, and it's also displaying the output it's giving to the amps. (ranging anywhere from 0-110 amps average is around 40-50 though)
So I thought maybe it was wiring, just did the Big 3 upgrade, 2 gauge welding cable, also no change.

Now the last option I can think of is the alternator (this is what every store is telling me, I need more power) But my issue with that is, how come when I got it a year ago, with the stock alternator, my lights hardly dimmed at all. (with the exact same setup, in fact minus the big 3 upgrade) and now it's all the sudden worse than it's ever been. (Even with the new alternator that I still have in there currently)

Nobody has yet to answer that question, they just say there is not enough input power to supply everything. If that really is the problem I will get a HO alternator (which I planned on doing when I first got my system).. Money is tight right now though, and I don't want to buy a HO alternator and for some reason have the same problem.

It would be appreciated if someone could explain why it's dimming now, and wasn't before with the same amp alternator, and if in fact I do need to upgrade to a HO alternator. Also if I do need to upgrade how much amps will be enough? (keep in mind a little dimming isn't a problem, like it was originally, but when it's dimming to about half the brightness, that is. It is also not JUST my headlights that dim either, my clock inside my car dims, my capacitor in the trunk also dims, pretty much any light source (I haven't noticed my deck dimming though))

Have you talked to anyone about looking into a capacitor?

As others have said, battery needs to be replaced. When the cranking amps have dropped, that generally means resistance inside the battery has increased (in your case, a lot).

The other big things to check are the ground cables to/from the battery, engine, and chassis. Assuming you're on the original cables as they from the factory, you're talking about 18 year old cabling. If you're in an environment that sees a lot of moisture, or worse - salt, your cables will be corroding on the inside. Problem is with newer style cables (pretty much anything after the mid 80's), it's not always obvious from the outside. Recently went through this with my Dad's '95 Ranger. Thought the starter went dead, so we replaced it. Still no go. Replaced battery and cleaned all the connections...nothing. He was sure the cables where fine because they looked clean. I cut the connector off the battery end of the positive cable, and sure enough - it was the classic crusty green of corroded copper. Replaced the cables, and it fired right up.

I'm not familiar with the setup of the Taurus, but I'd assume the alternator is grounded through the bracket attached to the engine, and the engine is grounded to the chassis via a ground strap (looks like a flat braided cable). In my personal setups, I always run a heavy gauge ground cable (min 8 gauge, although I'll typically run 4 gauge) straight from the alternator's case to the negative terminal of the battery, as well as a heavy gauge power cable from the terminal on the alternator to the positive on the battery. This eliminates the problems associated with mutiple connections to the battery (case to bracket, bracket to engine, engine to braid, braid to chassis, chassis to battery, consolidating it to just case to battery). The factory can get away with a much smaller wire, and poorer grounding as the alternator typically is only running high load for a few minutes following the engine starting, not constantly pushing a high load as is required with a high powered stereo system.

Of course, make sure all your stereo related connections are good and tight. I'd recommend against the typical set screw ran down on bare cable method, and prefer that all cables get terminated with ring terminals, and properly secured on studs.