SSC P4 Q's and HEADLAMP MOD

Can the SSC P4 be run direct drive off of one Standard 123 cell?
Different mod in mind, but need to know
Just shorter battery life?


Now for the #1 MOD I have in mind..................
I have read the SSC P4 is 3V min. & 3.8V Max.
Is this correct?
If I run 3 of these in series, would the input voltage remain the same?
I have an upgrade in mind, but don't want to blow this emitter.
I have a Princton tec headlamp with an array of three 5mm emitters and an two level (Low & High) incandecent in the middle, I used my multimeter to check the voltage on the LEDs and it read 3.3Volts. It takes two 1.5V AA cells and an optional four C cell bettery pack for the incandecents high mode. The light works with the 2 AA cells.....JUST NOT HIGH MODE.
I would like to do away with the incandecent, it projects a terrible beam with LOTS of artifacts
I checked the voltage to the incandecent bulb and it reads:
LOW: 2.9Volts
HIGH: 2.9 Volts
If I replaced the incandecent with the P4, is there a way to have both low and high modes? Or will it stay the same since the voltage seems to remain the same? Even if I can just use one mode with the P4, it will be 1000 times better than this ugly bulb.
There is a rather large converter board about 1.5 inch in diameter with all the LEDs and bulb mounted to it.
I only know very basic electronics so any help would be greatly appreciated!

DaFABRICATA said:

Can the SSC P4 be run direct drive off of one Standard 123 cell?
Different mod in mind, but need to know
Just shorter battery life?

Click to expand...

I don't think so. Under load, a standard 123 cell is at about 3.0 volts shortly after it starts discharging, then drops to 2.5 near the end. Depending on the individual LED, you'll get some light for a short while at the beginning, or no light at all.

Now for the #1 MOD I have in mind..................
I have read the SSC P4 is 3V min. & 3.8V Max.
Is this correct?

Click to expand...

Yes and no. It's 3.0 - 3.8 volts at 350 mA and 25 degrees C. At higher current the voltage will be greater; at higher temperature it'll be lower.

If I run 3 of these in series, would the input voltage remain the same?

Click to expand...

No, the voltage will be the sum of the three LED voltages.

I have an upgrade in mind, but don't want to blow this emitter.
I have a Princton tec headlamp with an array of three 5mm emitters and an two level (Low & High) incandecent in the middle, I used my multimeter to check the voltage on the LEDs and it read 3.3Volts. It takes two 1.5V AA cells and an optional four C cell bettery pack for the incandecents high mode. The light works with the 2 AA cells.....JUST NOT HIGH MODE.
I would like to do away with the incandecent, it projects a terrible beam with LOTS of artifacts
I checked the voltage to the incandecent bulb and it reads:
LOW: 2.9Volts
HIGH: 2.9 Volts

Click to expand...

Now you know the voltage the batteries deliver at the particular current being drawn by the lamp and at the particular state of discharge of the battery. It will differ considerably as the battery discharges and if you change the load.

If I replaced the incandecent with the P4, is there a way to have both low and high modes? Or will it stay the same since the voltage seems to remain the same? Even if I can just use one mode with the P4, it will be 1000 times better than this ugly bulb.
There is a rather large converter board about 1.5 inch in diameter with all the LEDs and bulb mounted to it.
I only know very basic electronics so any help would be greatly appreciated!

Click to expand...

My guess is that the incandescent is being directly driven from the battery (virtually always true as far as I know) and the voltage to the LEDs is being boosted by the converter. I don't know how they're handling the "low" and "high" modes. Overall, I don't think this is a good project for you.

c_c

Have you thought about using a protected R123 (rechargeable)?

That may slightly overdrive the P4 at first in DD, but not for long.

From then on its quite a long curve where the P4 is still driven at
enough current to give it great output before the circuit shuts off
to protect the R123.

For direct driving a P4 LED with a Li-Ion cell, I recommend adding a small series resistor. I've found that about 0.39 ohm or so is about right, but the optimum value would depend on the cell type and individual LED. I size the resistor to provide about 1A of current to the LED when the battery is fresh. (The best way to measure the current is by measuring the voltage drop across the series resistor and finding the current with Ohm's law.) The resistor will also keep the current more constant as the battery discharges. With 0.39 ohm, the efficiency reduction is around 10% at one amp, less as the battery voltage drops. You can get chip resistors of this value from the Sandwich Shoppe.

c_c