George Khawahie

I installed a pair of aftermarket foglights on my IROC. They are directly wired to the battery and a switch. There is no relay included with the kit. My stock IROC foglights shorted out and I couldnt trace the short so I just installed a new pair of foglights that log OEM. Anyway, the "problem" if you can call it that is that when the foglights are on, the voltage needle drops low and stays low while there on. While I dont see a difference, I'm worried that I am putting strain on my alternator which my stereo is already taking. The stereo dosent affect the voltage at all. If I wired in a relay, will it fix the problem? My stock IROC foglights didnt make the voltage needle dip like these aftermarket lights. I'm assuming the relay helps. What do you guys think?

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1988 Camaro IROC-Z Convertible
www.khawahie.com
www.cobrastrike.com
E-Mail: george@khawahie.com
AIM: DVDphile
ICQ: 11114622
Voice Mail: 800.222.6000 / Mailbox # 94665000
The guy with the TV and DVD Player in his IROC, and is currently the most mechanically challenged member of the All-Powerful Nor-Cal crew.

Matt84TA

YES! Wire in a relay. If you aren't using heavy guage wire, that is another electrical fire waiting to happen.

Stuart Moss

George,

Since you wired the lights directly to the battery (through a switch), the only thing that could affect the voltage of your vehicle would be the current draw from the two lights. Some questions:

1. What is the voltage BEFORE it drops?

2. What voltage does it drop to?

3. What is the engine RPM when the voltage drops?

4. Does the voltage increase with an increase of engine speed?

5. Does the voltage drop with all power hungry accessories (heater fan, radiator fan(s), headlights, stereo, etc.) "off"????

6. What are the voltages with the fog lights on/off with with all accessories "on" (lights/fan on high/radiator fan(s), etc.)?

If the voltage drops with an engine speed of over 1500 RPM, then it sounds like the alternator is unable to provide the additional current to power the two additional lights. If that's true, then you're operating near the limit of your alternator's output, and an upgrade (more powerful) may be in order.

It is normal for the voltage to drop at/near idle speed, especially when several accessories are used.

Use of a relay as stated above would be desired.

George Khawahie

The stock wires are waifer thin. I went ahead and used 10 guage car stereo power cable.

1. Its at 13 give or take a tiny smidge. As soon as the fog lights go on.

2. It dips down between the 13 and 8. Just above the white little mark above the 8. It stays down until the fog lights go off.

3. Havent noticed.

4. Not when the fog lights are on. If there off and i'm bumping the stereo and I get on the freeway, yes it will go up a little. With the foglights on, weither i'm going 25 or 85, the battery level dosent change.

5. Not at all! Thats the weird thing.

6. Even with everything running, including the stereo blasting, headlights on with highbeams, rolling windows down and up, it still stays a notch below 13. The only thing causing it to drop so much are the foglights.

The stock foglights didnt make the needle go down like this. I was able to turn all the the lights on including the stock foglights and the power would be just a smidge under 13.

My alternator is new btw.....

What purpose would the relay serve?

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1988 Camaro IROC-Z Convertible
www.khawahie.com
www.cobrastrike.com
E-Mail: george@khawahie.com
AIM: DVDphile
ICQ: 11114622
Voice Mail: 800.222.6000 / Mailbox # 94665000
The guy with the TV and DVD Player in his IROC, and is currently the most mechanically challenged member of the All-Powerful Nor-Cal crew.

George Khawahie

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QUICK305

Well if its any consolation, my car drops that low while Ive got my air and fans on with my *factory* fog lights

Stuart Moss

Geroge,

Thanks for the information.

First, one purpose (there are many) of a relay is to allow you to switch a lot of current using small guage wire and a small (current wise) switch.

If you didn't use a relay, you'd need to run the large guage wire from the device to the switch and also to the power source --- more importantly, you'd also need a switch rated to handle the current which are very often not available or desirable.

BTW, I know you already put in 10 ga. wire, which is fine, but 12 ga. would have been more than enough for two fog lights, 14 ga. probably being adequate for two 50 watt bulbs. One of these days I might post a chart for proper wire size usage dependent upon current and length.

Regarding your problem (and tks for the info), since the problem occurs only with the fog lights on (and everything else "off"!), it appears that the problem is not due to the alternator not being to handle the additional current (like "QUICK305" posted - although that should only happen at idle - if it happens at highway speed, then your alternator is too small).

I know you stated that you wired the fog lights directly to the battery (I presume directly to the battery posts, right?). Does that mean that you wired the ground of the lights directly to the battery terminal also? If not, where did you ground them?

Also, does the voltage drop if only ONE light is lit? If so, try this test with just the other light. Does the voltage still drop? Just for giggles, try turning on your circuit without ANY bulbs in your fog lights. Does the voltage drop?

[This message has been edited by Stuart Moss (edited July 28, 2000).]