Will my headlights be brighter with 14v+ over 12.5v+?

[DroppedZ84]

So I went and did all the voltage testing today, on my electrical system..found out a few things. All tests were done at 2000rpm:
Alt Voltage = 14.0
Bat Voltage = 14.0
Junction Block Voltage = 14.0
Fuse Block "Bat" Voltage = 14.0
Headlight Voltage = 12.5...this didn't change going from idle-2000rpm, it stayed right at 12.5.

My question is, would my lights be BRIGHTER if I had 14.0v+ at the lights? Or are they putting out 100% at 12.5v+? Thanks!

[SlapFish]

I think they're at 100% with 12 volts. If anything above does make them brighter, they'll burn out faster because of increased wattage.

[boxrodz]

Like SlapFish posted, you're near the design voltage. I believe most headlamps (square or round) for these trucks are designed to operate at 12.8 volts. Some of the manufacturers of high performance headlamps warn against operating them above 14 volts, otherwise they may shatter. I'm not sure on the standard halogens. So, you're close to operating voltage of optimal brightness.

[Dwn2rth76]

I believe when I had my 72 SWB I found a resister in the headlight feed to limit voltage and like stated above to prevent bulb burn out. What you should be more concerned with is if voltAGE drops below 12vthen they dim.. hope this helps ........

[Russell]

I've been running my 89's high beams at 14.6 volts for several months now. It makes them nearly twice as bright as they were at the 11 some volts they were at before, and I haven't burnt one out, so I am personally a fan of running relays to hook the lights straight up to the battery.

All newer vehicles are run this way as well -- Voltage straight from the battery straight to the headlights via a relay. Also greatly reduces the amount of higher amperage current you have flowing inside the cab

[DroppedZ84]

Originally Posted by Russell

I've been running my 89's high beams at 14.6 volts for several months now. It makes them nearly twice as bright as they were at the 11 some volts they were at before, and I haven't burnt one out, so I am personally a fan of running relays to hook the lights straight up to the battery.

Well, also, on MadElectrical.com, they said if you have less than 13.5V+ at the lights, then upgrading to relays, will make the lights brighter...now only if I could find a way to do this upgrade to my OTHER car, I would be dancin in the streets!

[LOHRTBT]

do you have a diagram or pics of how you did this?? sounds like a cool lil upgrade.

[7T7]

here ya go...
http://www.madelectrical.com/electri...adlights.shtml

[Zoomad75]

There was a large discussion here on adding relays last month. Short version, stock system sucks, adding relays to get direct system voltage will make stock lights brighter. Add H4 conversion bulbs and they will get even brighter over halogens running 14v. Mike was nice enough to take our write up and put it on his site for quick reference:

http://www.73-87.com/7387garage/exte...ight_relay.htm

Eliminating the stock built in voltage drop will make your lights brighter.

[DroppedZ84]

Originally Posted by Zoomad75

Short version, stock system sucks, adding relays to get direct system voltage will make stock lights brighter. Add H4 conversion bulbs and they will get even brighter over halogens running 14v. Eliminating the stock built in voltage drop will make your lights brighter.

OK then! I'm considering getting the LMC kit, just for ease of use..but if it's the same price as Mad's kit ($50) then forget it, I can get 2 Relay for $5 and all the wire I need for FREE!

[Zoomad75]

The LMC kit is cheaper. I think 20-30 bucks. But, it does not include any fuse protection for the power supply to the relays. Add That cost to the LMC kit. The LMC kit is decent even if the instructions suck. But if you don't mind doing it yourself its not hard to put it together.

[Bad Karma]

I have the LMC kit on my Suburban. The lights are noticeably brighter, plus I don't have all the headlight current running through the light switch anymore.

The wires on the LMC kit are just barely long enough to hook everything up, my relays are hanging from the core support right next to the battery. Someday when I feel ambitious, I will extend the wires to put everything where I want it to be.

Overall, not a bad kit for the price, and the instructions are in "Broken English", which is good for a laugh.