Headlights seem are dim. Is it possible I need a bigger alternator?

[adam355]

I have a lot of aftermarket stuff running of the car's power, but nothing too out of the ordinary. AFC, Walbro 255, 4 different gauges, exc... Anyways if I turn the heat on, headlights on, power windows, exc.... any interior lights will get dimmer. Thats not really an issue, but the fact that my headlights seem kinda dim is. I mean it can be really bad especially in the rain I will even question if they are even on. I do have the red top Optima battery if that helps. So I'm basicly just wondering if this is normal and if a bigger alternator would solve my problem? Thanks

 

[LAUNCHED]

With the car running, take a mulitmeter and check the voltage up at the battery, this will tell you how many volts your alternator is putting out. Should be somewhere around 13.3 Volts if I remember correctly.

Also make sure your connections don't have any corrosion on them, this will cause your problems as well.

If you are worried about it, you could always tried the 100amp alternator out of an auto. Also Canada built cars use bigger alternators because the country requires day time running lights. I am not sure about the whole country but I know in Thunder Bay Ontario they do.

CRAIG

 

[adam355]

Wow, forgot I posted this. Anyways I get like 13.9 volts at idle with small dips to like 13.5-13.8. So I think I am ok. Anyways I still have the dim headlight problem so if anyone has any other ideas please shoot.

 

[luv2rallye]

Wow, forgot I posted this. Anyways I get like 13.9 volts at idle with small dips to like 13.5-13.8. So I think I am ok. Anyways I still have the dim headlight problem so if anyone has any other ideas please shoot.

What voltage do you get when you have all the stuff on? With everything off (except engine) you should get 13.9-14.9v at 68 degrees F. With everything on you should never go below 12v or you need a different alt. If you're above 13.9v and your headlights are still dim then you've got a poor connection to the headlights (eg. corrosion in connectors, loose connections, etc) or your headlights themselves are getting old.

 

[BlandAnalogy]

whats the amperage rating on your ac generator? thats basicly like throwin a vat-40 on that car and putting a full load on the generator (alternator)... i dunno how many times i have to mention this machine but you really need to hook up a vat-40. and generally with a running alternator you would be measuring amperage. keep in mind that it should be hooked up in series unless you wanna blow a fuse.. using a dmm would be a 2 man job considering that you'd need to increase rpm's to 2000. otherwise you wont get any decent or precise readings. id suggest getting a higher amp rating ac generator. you also might wanna check out the diode on the generator.

 

[ClevSilverEclip]

Sylvania Silverstar bulbs - and definitely check to see that your headlight lens isn't yellowed/clouded over.

-A
/

 

[luv2rallye]

.....you really need to hook up a vat-40. and generally with a running alternator you would be measuring amperage....... using a dmm would be a 2 man job considering that you'd need to increase rpm's to 2000.

Let's be practical. Most people don't have a vat-40 or a 100 amp ammeter lying around in their garage. Just use a simple multimeter ($10 at Radio Shack) set to measure volts (or dmm - digital multimeter) on the battery and it will be adequate for this test.

And you can increase rpm's to 2000 (value is not critical - just faster than idle) yourself at the same time by just pulling on the throttle cable under the hood. This is a very simple test anyone can do (even you adam355)

 

[BlandAnalogy]

that is true but if you want the car diagnosed the best way goto a vat-40. to me it's no big deal because i can just take it into school and use a vat-40. by the way there is an ampmeter on a multi meter. but using a multimeter while checking out the ac generator also makes it a 2 man job...

 

[BlandAnalogy]

i was really hopping that sombody would point out the correct way to test an alternator. but nobody pointed it out. when you test you are supossed to read amperage and voltage at once. we've already talked about this a bit but just never got the response i was hopping for. anyways good luck on your project bro.

 

[polarmoment]

Sylvania Silverstar bulbs - and definitely check to see that your headlight lens isn't yellowed/clouded over.

-A
/

my money's on this as well. how old are your headlight bulbs? on my work car (99 eclipse) the bulbs were originals, but had so many hours on them that they were EXTREMELY dark- so bad i could barely see at night. i replaced them with new regular old sylvanias and the difference is amazing. pull your old bulbs out and check them before you go to the hassle of troubleshooting the electrical system.

 

[adam355]

my money's on this as well. how old are your headlight bulbs? on my work car (99 eclipse) the bulbs were originals, but had so many hours on them that they were EXTREMELY dark- so bad i could barely see at night. i replaced them with new regular old sylvanias and the difference is amazing. pull your old bulbs out and check them before you go to the hassle of troubleshooting the electrical system.

I will do that, thank you. I'm pretty sure the bulbs are old as sh*t.

 

[xXeclipstasyXx]

check and make sure your ground is good, i was having the same problem but only with the power windows... i tightened up my battery cables and the ground was moderately loose, it didnt completely fix the problem but i did notice a difference. if not its probably alternator.... you often run into this problem when running a high powered soundsystem... just too much power draw for the stock alternator.