headlite upgrade

[mickelsdogs]

which of the relays should be enough to brighten the head lites without draining the battery and giving the ampmeter a work over. 30amps for both high n low or do I need more?

[Chryco Psycho]

The headlights do not pull near 30 amps so 30 amps is fine , they wont drain the battery they are just an electromagnetic switch . The relays use milli amps for power when in use

[mickelsdogs]

duh relay dont use much 2 work!!! what about the robbery of battery  power when relay  is hot?   makin 30AMPS  H O T from battery 2 headlamps all4 Igniton is on 2ND field of alt chg system . will this work

[myk]

Translation in progress...

[elacruze]

The relay adds only about 3/4 amp per relay. A 30 amp relay can carry 30 amps, but it's only a switch. It adds nothing beyond the control requirement.

[Bob T]

duh relay dont use much 2 work!!! what about the robbery of battery  power when relay  is hot?   makin 30AMPS  H O T from battery 2 headlamps all4 Igniton is on 2ND field of alt chg system . will this work

I think what he is asking is;
a) Is it better practice to feed the lights via the relay direct ( fused ) off the alternator or
b) Is it better to feed the lights via relay direct ( fused ) off the battery

I would say take them off the Alt because it gives the battery a chance to recover with trickle feed 

Nacho??

[Chryco Psycho]

Lets try it this way ........   a typical 55 watt headlight needs approx 4 amps at full power
the relay is a switch that is switched with electrically , so you take power from the battery terminal on the relay & switch it to the headlights directly instead of taking power through the bulkhead connector , then the ammeter , then the headlight switch then the dimmer switch & back through the bulkhead connector to the lights .
When you turn on the headlights it uses a small amount of power to close the electrical switch to send power to the lights .
The 30 amp rating is the max amount of power the relay can switch so using a 30 amp relay to switch 4amp X 2 headlights load is well within the range of the relay .

[Bob T]

Lets try it this way ........   a typical 55 watt headlight needs approx 4 amps at full power
the relay is a switch that is switched with electrically , so you take power from the battery terminal on the relay & switch it to the headlights directly instead of taking power through the bulkhead connector , then the ammeter , then the headlight switch then the dimmer switch & back through the bulkhead connector to the lights .
When you turn on the headlights it uses a small amount of power to close the electrical switch to send power to the lights .
The 30 amp rating is the max amount of power the relay can switch so using a 30 amp relay to switch 4amp X 2 headlights load is well within the range of the relay .

Ok, so option b) then Chryco .
I'm no good at cad images so I roughed this up, works on my 68

Splice wire 4 Violet trace and feed relay coil R1, the other side of the 4 wire goes on to the normally open contact of R1 and then off to headlight as per factory.
splice wire 6 red and feed relay coil R2, the other side of the 6 wire goes to n/o contact of R2 and then to headlight as per factory

[Chryco Psycho]

http://www.cuda-challenger.com/cc/index.php?topic=72368.msg737900#msg737900

[macca3441]

The hand-drawn diagram that BobT presented looks the goods! But only if you're retaining your original lights, or sticking with the same wattage lights!
However, if you upgrade your lighting system to higher wattage lights, you'll need to seperate the inner highbeam lamps so they're powered by their own relay.
Otherwise, you'll have too much current draw for just one relay!

Wade

[Bob T]

Ah, it is for upgraded headlights thats why there are two 30A relays R1 & R2....probly just the crook way I've drawn it makes it a bit harder to follow...

[macca3441]

Sorry mate....you've mis-understood!
If you've increased your wattage the smart thing to do would be to use a relay for low beam, a relay for outer high beam, and another relay for inner high beam! 3 relays in total!
I've got a "twin relay" arrangement for the outer lights (low and high beam), and another relay for the inner high beam!
My low beam lights are 80w each (which draws approx 13amps), and my outer high beam are 100w each (approx 17amps), and same for my inner high beam!

Wade

[68neverlate]

Here's a thread containing a schematic from John Kunkel for a headlight upgrade that may be of interest... this is the upgrade I'll be tending to in the fall.  John suggests using 2 - 30 amp fused relays.

http://www.dodgecharger.com/forum/index.php/topic,84689.msg952219.html#msg952219

Hope you find it helpful...  

[macca3441]

the two relay system will work fine for the standard wattage globes.
Problems can/will arise when the wattage is increased.....more wattage = more current draw!!

Wade

[Bob T]

Sorry mate....you've mis-understood!
If you've increased your wattage the smart thing to do would be to use a relay for low beam, a relay for outer high beam, and another relay for inner high beam! 3 relays in total!
I've got a "twin relay" arrangement for the outer lights (low and high beam), and another relay for the inner high beam!
My low beam lights are 80w each (which draws approx 13amps), and my outer high beam are 100w each (approx 17amps), and same for my inner high beam!

Wade

Ok, I can see your point, but, I still think even with increased wattage 2 relays with adequate protection will work fine as the 4 headlight circut is still covered by the existing ( new ) Relay R2 inserted into the red wire circut L3A-116R

I thought Johns diagram was good, pretty much the same as my version , just prettier    , didnt know it was on here otherwise I would've linked it.

Chryco, that is a good diagram too but it gets a bit more complicated wiring wise with an extra switch and relay doing a more fail safe version, all personal choice I guess.

[mickelsdogs]

john kunkels Diagram Perfect NO OTHER WAY.did mine that way. Now i get to see the pix. THANK YOU  4 the enLIGHTment

[John_Kunkel]

It's not actually MY diagram, I pirated it from some other source.

If the wattage exceeds the 30-amp relay's limit, rather than add more relays, I'd just go to two 40 or 50 amp ISO relays (and larger wires if needed).

[autodynamics]

Use 2 separate relays one for each headlight and fuse them separately !
One will work but 2 is logical and more thorough

[FLG]

2 relays 2 fuses....wire it up to one and if the relay/fuse blows when your driving down a pitch black road youll be wishing you had at least one set of lights working.

[Bob T]

2 relays 2 fuses....wire it up to one and if the relay/fuse blows when your driving down a pitch black road youll be wishing you had at least one set of lights working.

Yes, good point..
But the Factory made do with one though, more about correct fuse rating for the load carrying capacity of the wiring..
Just threw it together quickly on Saturday night before a club run on Sunday, needs a bit of a tidy up, relays are mounted to the ali battery tray strut that I made , was missing the original one so I didnt feel bad about drilling holes in it

[izzyinNorcal]

2 relays 2 fuses....wire it up to one and if the relay/fuse blows when your driving down a pitch black road youll be wishing you had at least one set of lights working.

Yes, good point..
But the Factory made do with one though, more about correct fuse rating for the load carrying capacity of the wiring..
Just threw it together quickly on Saturday night before a club run on Sunday, needs a bit of a tidy up, relays are mounted to the ali battery tray strut that I made , was missing the original one so I didnt feel bad about drilling holes in it

I'm new to the forum and have been following this thread. I'd like to do the relay upgrade - seems pretty straight forward - but can I put the relays behind the dash and patch into the existing wiring harness?

Izzy

[2Gunz]

Yes you can.

However..........

The purpose is to take all the crusty wire, 40 years of oxidation, junk when new headlight switch and floor switch and get it out of the path of power for your headlights.

With the relays at the headlights the old stuff just becomes a "trigger" for the new setup.

Putting the relays inside the car at the very least will make you reuse the old wiring...... which defeats the purpose.

If your asking this for cosmetic reasons, buy good relays and put them under the battery tray and forget about it.


I wouldnt spend much time thinking about this upgrade. It is one of the cheapest and best things you can do for your car.