resistor? or potentiometer? HEEELLPPP!!!!

[bebo_911]

I came up with a nice little project and my question is, hypothetically speaking, i want to reduce voltage for like a headlight bulb. I want to reduce the 12 volts into like 6 volts. What kind of resistor would i have to use? Or do i have to use a potentiometer? Reducing headlight output is a dumb idea and thats not what im going to do, its a similar aplication. I just need a crash course on resistors.

[evil_demon_01]

Resistor.
You could even use a Zener diode.

Look up Voltage divider circuits.
Heres a Wiki link - http://en.wikipedia.org/wiki/Voltage_divider
How many amps will the component you want to use need?

Something like this will work.

[cp[mike]]

will headlights even illuminate at 6V? resistor and potentiometer perform the same function, except the pot is adjustable, resistor is fixed.

to give you a start, youll need to know the desired current flow to the bulb (how many Amps?) - something you can measure, but it will vary greatly because it changes as the bulbs warm up. what are you even trying to do? read up on Ohms law if you are curious about resistors and power in a circuit: http://www.allaboutcircuits.com/vol_1/chpt_2/1.html (great explanation!!)

[sonikaccord]

I came up with a nice little project and my question is, hypothetically speaking, i want to reduce voltage for like a headlight bulb. I want to reduce the 12 volts into like 6 volts. What kind of resistor would i have to use? Or do i have to use a potentiometer? Reducing headlight output is a dumb idea and thats not what im going to do, its a similar aplication. I just need a crash course on resistors.

Voltage division as mentioned earlier. How much power is this project pulling? Amps?

Also you can use a resistor and a pot together to have an adjustable voltage divider

[evil_demon_01]

He said via PM he wanted to use the headlights as DRL's.

The stock bulb @ 55W 12V uses about 4.5 Amps
Dropping this to 6V is about 9 Amps.

I thought he may have been able to use a LM317 voltage regulator, however it has a Max output current of 1.5A.

Any resistor he uses is going to get pretty hot trying to remove that much current / power. The power will also drop which should drop the current, but it will still be a fair amount of current.
Which is why I now think a regulator circuit will probably be a better option.



That or just buy a DRL module and all the work is already done for you.

[cp[mike]]

He said via PM he wanted to use the headlights as DRL's.

The stock bulb @ 55W 12V uses about 4.5 Amps
Dropping this to 6V is about 9 Amps.

I thought he may have been able to use a LM317 voltage regulator, however it has a Max output current of 1.5A.

Any resistor he uses is going to get pretty hot trying to remove that much current / power. The power will also drop which should drop the current, but it will still be a fair amount of current.
Which is why I now think a regulator circuit will probably be a better option.

That or just buy a DRL module and all the work is already done for you.

this was my concern as well, knowing it burns 55W the resistor is going to have to be massive (in size)

DRL modules handle timing/switching on and off, and run the headlights somewhere around 9V. at least the Insight modules did, i assume others probably do similar (Insight arent around anymore)

[bebo_911]

Im going to definetly look into the voltage regulator. Also the DRL module. I had no idea they existed. I guess it's true what people say, if you have an idea, someone already had it. Thats a million for the info Evil.

cp[mike]: Thanks for the link. A great circuits for dummies explanation. Hell i had no idea Ohms was the measurement of resistance.

[ChIoVnIdCa]

this was my concern as well, knowing it burns 55W the resistor is going to have to be massive (in size)

\

x2... You will need a high current resistor and probably some sort of heat sink....


Ill give you a test...I know on 5th gens at least for sure if you power up the high beams at the bulb itself the low beams come on.. So you would have to isolate the highs from the lows... If you are doing the drl in the highs..


Another option would be to drill and mount an amber bulb into the housing... Like on a GM....

Another way is to wire the headlights in series... It would cut the voltage in half... Approx 50% output ...I can think of a couple ways to do this.... Least amount of relays I can think of is 4 and a lot of wiring

[James Matteu]

OEM daytime running lights

The Mitsuba DRL module used on all Honda and Acura model through the 90s is basically a box with two relays. The relays select voltage going to the headlights based on the position of the headlight switch. With headlights off, the relays send 10A to the headlights. With headlights on, the relays send 20A to the headlights using the stock headlight circuit that everyone has. The rest of the components on the bread board in the DRL Module are there to detect voltage on the headlight circuit so you know if they're working. If the voltage isn't there when there should be, those components switch on the DRL Malfunction Indicator Light. Ask Canadians about that blue dash light coming on when the module fails.

Have fun DRL man.

[bebo_911]

The Mitsuba DRL module used on all Honda and Acura model through the 90s is basically a box with two relays. The relays select voltage going to the headlights based on the position of the headlight switch. With headlights off, the relays send 10A to the headlights. With headlights on, the relays send 20A to the headlights using the stock headlight circuit that everyone has. The rest of the components on the bread board in the DRL Module are there to detect voltage on the headlight circuit so you know if they're working. If the voltage isn't there when there should be, those components switch on the DRL Malfunction Indicator Light. Ask Canadians about that blue dash light coming on when the module fails.

Have fun DRL man.

Is there any way that module can be used in the high beam? I want to use my high beam as the DRLs. I have HIDs on my lowbeams so the voltage drop will make them flicker and fail. Also i noticed most if not all stock DRLs are on the high beams.