Big hauler headlight voltage?

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Highball18

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I am planning on wiring the headlight in my battery converted ten wheeler to the battery before the speed control so that when the loco is on, the headlight is on at full brightness. I am using an 18v drill battery for power. Will I need a resistor to avoid blowing the headlight?
 
It depends how you wire the battery conversion

The headlight voltage (front and rear) is 5v. If you provide the battery power to the leads that provide the normal track supply, then you won't have a problem.

If you have an old bug mauler, and are stripping out all of the electrics, then you'd do better with a 5v constant voltage supply to the headlamp and Neil Robinson (of this forum) will be able to provide you with a wiring diagram and a list of components ;) ;)
 
Rhinochugger said:
It depends how you wire the battery conversion

The headlight voltage (front and rear) is 5v. If you provide the battery power to the leads that provide the normal track supply, then you won't have a problem.

If you have an old bug mauler, and are stripping out all of the electrics, then you'd do better with a 5v constant voltage supply to the headlamp and Neil Robinson (of this forum) will be able to provide you with a wiring diagram and a list of components ;) ;)
Click to expand...
Other forum members are available! ;) ;) ;)
 
PhilP said:
Other forum members are available! ;) ;) ;)
Click to expand...

Yes, I think it was just that Neil was first up when I needed one - that was a year or two ago ??? ??? ???
 
If you are rewiring I'd just use and LED with a resistor to limit the current (calculator available on the net) connected to the battery via an ON/OFF switch.

That's what I have done on all my locos.

I actually include a CHARGE position on my switch so that I do not have to remove the battery for charging.

Advantage of LEDs is the small current draw usually around 20mA so even if it is left on it would take ages to discharge the battery.

If you still want to use the incandescent then a 7805 5V regulator to drop the voltage then a resistor in series with the globe to regulate current to stop the regulator from getting hot 120 ohm will limit the current to 150mA you may have to adjust the resistor value because the brightness may be affected. Best way is to get a variable resistor and adjust it till you get the required brightness then measures the resistance then select a resistor close to the value.
 
LED sounds good to me! All of the factory electronics in the tender are gone. Adding a regulated power supply seems way too complicated just to light a bulb... Less power draw is also an advantage... Thanks guys!!

Oh, the headlight will be wired in after the main on/off switch but before the speed control. Constant lighting, on when the loco is on, off when the loco is off...
 
I know this thread is a couple years old, but I'm finally doing the led conversion! I was rummaging through some old train stuff and found a bag of "soft yellow" led's with resistors I bought ages ago. I've got the led mounted in the headlamp housing, now I just need to run some wires back to the tender to connect to the locomotive's on/off switch...
 
If you want a type of directional lighting you could try wiring LEDs in reverse polarity to each other across the motor tabs so when the motor is turning FWD the front light is on and vice versa.

That is how I have done my locos, a disadvantage is that the lights are not on when the motor volts are low i.e. when stopped or just crawling but I live with that.
 
Great idea! However, for this engine I didn't really want directional lighting, constant brightness was more important to me...
 
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