Overcharging...

[max pain]

Hi everyone!
Couldn't find any info on what i'm going to ask you... (sorry if i missed something)

About a month or two ago my right headlight started to freak me out. At first the bulbs started to burn out and at last i found the cutoff point (or whatever the thing that clips on the bulb is called) to burn out inside too. I changed it several times, tried to use different bulbs, but in a week or so i had to change something again and again. My mechanic told me, that sometimes this happens and suggested to use less powerful bulbs. At last i came to my machanic once again and had him check the voltage, that came to the bulb and overall voltage, that the car produced. And what did he find out? He showed me, that the generator produced about 14.7 - 15 volts (with normal 13-13.5 as i know). Even when i turned on anything, that consumes electricity, the voltage didn't fall less ,than 14.5. He said that no wonder my bulbs went out so often and that i was lucky nothing else did...

Now as i hear with such kind of sh*t happening i have to fix the cars computer, which tells the generator to produce so much volts. (which is going to be pretty pricy, i guess)

Has anyone had such a problem?
How did you fix it?

 

[ShafferNY]

A healthy charging system usually puts out about 14 - 14.5 volts. @ 2000 rpm.

My KJ runs just over 14 right now. I've got one of those testers you plug into the 12volt power source.

Most modern alternators have an internal voltage regulator inside the alternator. I don't think that's your problem though.

 

[ShafferNY]

I had to go out to my vehicle anyway so I thought I'd check the exact output.

13.9 at idle(600rpm)
14.1 at 2000rpm.

Just fyi.

 

[Dave]

If you replace a bulb and touch it with your hand/fingers the natural oils in your fingers will get on the bulb and prematurely burn it out. Wipe the bulb clean with rubbing alcohol if you touch it/or use a CLEAN rag or something when you handle it. They will last much longer.

Your voltage output is within normal specs.

Dave

 

[max pain]

Thanks for your answers.
I'm familiar with the thing that the bulb can not be touched. The problem is, that it's about 5 new bulbs within a month and 3 new wiring...it can't go wrong so many times within such a short period.

Mine outputs about 14,7v and when the fan starts working the voltage jumps for about 0.3 back and forth, is that what you have aswell?

By the way the voltage was measured right from the battery and the generator.

 

[ShafferNY]

I would say you're slightly on the high side of where you should be with the voltage.

I'm not totally convinced it's enough to do the damage you describe though.

I'm wondering if you have weak battery, or possibly a low acid level in your battery.

What happens is, when you have a weak battery the alternator is constantly trying to charge it, but it never gets charged and your alternator is constantly putting out a higher than normal voltage.

Make sense?

I've seen it happen.

 

[max pain]

Yeh, kinda hope it does make sense...
I'm pretty sure the battery is 6 years old, but shouldn't the computer tell if something's not right with it (battery)?

 

[sevenhelmet]

Nope. The computer won't tell you jack about the battery; the only electrical issue you get a light for is low system voltage. BTW, your system voltage is fine- 2 or 3 volts above battery voltage is what you want for proper charging.

The battery on my KJ recently died without warning, and it wouldn't start one day. No idiot lights, she just wouldn't turn over. 6 years old is ANCIENT in car battery years! I strongly recommend you buy a new battery and see if that fixes your headlight problem. Your alternator also won't have to work as hard to charge it.

If that doesn't work, try changing the alternator. Headlights tend to blow from spikes and surges in the system, as well as improper voltage, but your voltage is within spec (as others have stated.)

 

[max pain]

Ok, now that'a a releif.

But isn't the alternator built into the computer?

And does anyone use 100x90watt bulbs? (I did before this started happening as they have white light, not yellow...)

 

[ShafferNY]

But isn't the alternator built into the computer?

The alternator is completely separate of the of the PCM.

http://www.familycar.com/Classroom/charging.htm#ALTERNATOR

 

[tjkj2002]

But isn't the alternator built into the computer?

The alternator is completely separate of the of the PCM.

http://www.familycar.com/Classroom/charging.htm#ALTERNATOR

But the voltage regulators in new vehicles(KJ included) are part of the PCM.

 

[ShafferNY]

You're right. I just took time to read the factory service manual. It seems as though it works on much the same principle.

I did notice something in there about a battery temp. sensor located underneith the battery tray. That's something new to me.

I'm not sure I'm too crazy about manufactures tying to cram every componet into one like I've seen on many of the new vehicles. I'm sure it makes troubleshooting easier to a point since there are fewer individual componets, but it seems like it would make repair more costly if you end up replacing a major componet like a PCM. That's a whole other topic. It's just a new way of doing things I guess.

 

[max pain]

You're right. I just took time to read the factory service manual. It seems as though it works on much the same principle.

I did notice something in there about a battery temp. sensor located underneith the battery tray. That's something new to me.

I'm not sure I'm too crazy about manufactures tying to cram every componet into one like I've seen on many of the new vehicles. I'm sure it makes troubleshooting easier to a point since there are fewer individual componets, but it seems like it would make repair more costly if you end up replacing a major componet like a PCM. That's a whole other topic. It's just a new way of doing things I guess.

That's what i was talking about, the voltage regulator is built in, it can be replaced or fixed, but it'll cost ya...

So how about it, does anyone use 100watt bulbs?
And maybe there are (i sure hope there aren't) people, that will say, that my 14.7 charging isn't normal...?
I'm gonna change my battery this weekend probably, see if something good happens (like extra horse power etc.)

 

[ShafferNY]

I'm just running whatever was in there when I bought it. Probably whatever is stock.

 

[max pain]

Thats 60/50 (or something like that).
If you buy 100watt ones, you'll see a huge improvement at night...

 

[ShafferNY]

The factory service manual states this for the headlamp bulb replacement.

EXPORT
CAUTION: Always use the correct bulb size and
type for replacement. An incorrect bulb size or type
may overheat and cause damage to the lamp, the
socket and/or the lamp wiring.
CAUTION: Do not contaminate the bulb glass by
touching it with your fingers or by allowing it to
contact other oily surfaces. Shortened bulb life will
result.

At this point I would say it's probably the hight wattage bulb causing this.

It's kinda odd that you've only had problems on the one side though. You think the other side would have failed if this were the case.

I suppose you could go back to a factory bulb and see if you have anymore problems. If you don't it would be safe to assume it was the higher wattage bulb.

 

[max pain]

Ofcourse this was the first thing i did (although i did think the same "if this is the case, both lights should fail, not just one") but it didn't help.

And again, the bulbs didn't fail themselves, the contact melted (the + responsible for low beam)

 

[jnaut]

Ok, now that'a a releif.

But isn't the alternator built into the computer?

And does anyone use 100x90watt bulbs? (I did before this started happening as they have white light, not yellow...)

No, the voltage regulator is built into the pcm. The alternator is the large silver looking thing to the right of the air conditioner compressor. Alternator needs a belt to drive it.

 

[LibertyOrDeath]

No, the voltage regulator is built into the pcm. The alternator is the large silver looking thing to the right of the air conditioner compressor. Alternator needs a belt to drive it.

Smart A$$. That's awesome nana.gif

 

[tjkj2002]

And maybe there are (i sure hope there aren't) people, that will say, that my 14.7 charging isn't normal...?

14.7volts is not bad,it's in the charge range and not harmful by any means.You may have a weak battery but might not,maybe heavy use of the electronic gizmo's in your KJ.

General rule of thumb is you wnat your alternator to produce 2-3 volts more then your battery output is so it charges your battery correctly.

My Battery(Optima Yellow Top) is sitting at 12.9volts,my alternator is putting out 14.84volts after startup and settles down to 14.45 after about 15-20min after the battery volts comes back up from the heavy draw from the starter.When using my winch my alternator is over 15volts easy trying to charge my battery.