How much current will PS2 headlight output handle?

It will have no problem with that load.  It's good for at least 250ma, as some configurations have four 6V 60ma bulbs connected to it.

It's not really plain DC, it's a PWM signal that varies between PV (18-24 VDC) and ground.  The net result is a voltage that "appears" to the bulbs as a 6V level.

One issue with the ngineering module will be that it requires PURE DC, not a PWM waveform as power.  It won't function connected directly, and will likely cook the module as the peak voltage exceeds the rating of the module.

I solve this by using a regulator circuit in series with the lighting output that supplies regulated DC.  I use the standard module that runs on 6-18V and use a 9V regulator for PS/2 headlight outputs.  While the effective voltage is 6V from the lighting output, the fact that it goes to at least 18V and usually more, allows you to have a steady low current 9v output.

Thanks John.  A simple voltage regulator like this?  Or are you suggesting a China eBay module?

This constant voltage board is one that Rod adapted from one of your designs. I assume the choke and rectifier would not be needed.

Bob

That would work fine, but I'm lazy, so I used the LM70L09 fixed voltage regulator, just three parts.  You can also use a 100uf or 150uf cap, no need for something as big as the 470.  You don't need a bridge or the 22uh choke either, just a simple diode.  Since the output of the lighting has nothing to do with the DCS signal, the 22uh choke isn't doing anything useful there.

Three parts, diode, cap, regulator.

GRJ, I looked through your many voltage regulator circuits but I couldn't find your secret sauce for smoothing out the PWM in the PS2 headlight circuit.

Is this what you described above, using 150uf 35v for C1, and skip C2?  

Can you use 1N4002 (3, 4, etc.) for the diode?

In my search, I found that Stan posted these scope tracings showing the PWM PS2 headlight circuit output:

I can see that the 22v pulse would not be kind to the Ngineering modules.  The full detailed thread is here.

Thanks

Bob

That scope picture is why you need a regulator.  If you just try to "filter" the headlight voltage, the cap would charge up to the peak voltage and smoke the ngineering simulator, it won't tolerate that high a voltage.

I'd use a small resistor, maybe 50-100 ohms, then a 100uf cap, and finally a three terminal regulator from 8V to 12V out.  The resistor before the cap is just to avoid any possibility if annoying the PWM driver with a peak power surge charging the cap.  Probably not needed, but then it only costs a penny and makes me feel better about not risking that output FET.

John

Is this correct? I could not find the LM70L09 (typo?).  I found the 78L09ACZ 9V (100mA) and LM7809CT 9V (1A) on Jameco.  Either one would be OK, right?

Thanks so much for your help with this.

Bob

No need to build circuits anymore, it’s all built in already for pennies using micro components. I just solder the 2 leads to the existing light source. Warm white LED’s draw very little current and stay constant from 3-17V on AC or DC.  Polarity doesn’t matter. With-in 10 minutes, you will have a better light than the old outdated original.

                                                         EVANS DESIGNS

SIRT

Yes, the Evans designs are a nice convenient no-fuss package and you don't even need to worry about polarity.   In this case I will be using a lighting module that does a nice MARS simulation. Here is the effect.  It requires pure DC, which is why GRJ is suggesting using a circuit to smooth out the pulsed DC.  For just lighting a white LED in the PS2 headlight circuit, all that is needed is the LED connected (in correct polarity) in series with a 220 ohm resistor.

Bob

@SIRT posted:

No need to build circuits anymore, it’s all built in already for pennies using micro components. I just solder the 2 leads to the existing light source. Warm white LED’s draw very little current and stay constant from 3-17V on AC or DC.  Polarity doesn’t matter. With-in 10 minutes, you will have a better light than the old outdated original.

The Evan's Designs LED's are useless for the intended application, the ngineering.com MARS module requires PURE DC, and drives a BARE LED.

Got to follow the actual thread and application to come up with a working solution.

@RRDOC posted:

John

Is this correct? I could not find the LM70L09 (typo?).  I found the 78L09ACZ 9V (100mA) and LM7809CT 9V (1A) on Jameco.  Either one would be OK, right?

Thanks so much for your help with this.

Bob

GRJ

Could you comment on this?

Thanks

That is fine, exactly what I was describing.  The regulator is generic, my number was a typo, it should have been 78 and not 70.