Micropuck + SSC P4

[Matt]

Hi all, I was hoping I could pick your collective brains a little please as there are holes in mine that need filling

I have an SSC P4, on a star, I'm intending to remove this from the star and replace the Luxeon on the cateye lamp I have (6v/4xAA). This is currently regulated through resistors. I have a plan to use a driver, namely a micropuck 02009-SHO. I have two of these but would idealy want to use one

I'm a little confused as to what I need to do to make sure I don't supply too higher voltage to the emitter (or puck!), I understand if I wire it up the puck will limit the current to 350ma, but this is where my understanding hits a brick wall :laughing:

I might be trying to marry up the wrong its and bobs for this, so feel free to flame me for noobness, any help gratfully received, thanks!

.

 

[znomit]

Application sheet tells you everything.

 

[Matt]

Thanks, I'd looked through this before but wasn't confident I had a complete grasp of it. I'm thinking I need to wire it in a buck/boost configuration as this would handle the 6v input, it states the maximum output voltage is 10v, what I don't understand is how I feed the Emitter with the correct voltage, which is about 3.7v. 10v would make it go pop! lol

Excuse my ignorance

 

[znomit]

Assuming you're running 4NiMH and one LED you'll have 4.4-5.2V input. Run as a buck driver.
Figure 5 shows the output curve over this range. Looks ok. When your cells start to run flat you'll have a fast drop off of output.
Figure 6 shows very good efficiency over this range.

If you wire as a buck/boost the efficiency is down 20%, though it may be better on runtimes if you plan on running alkalines.

ps, Planning on doing the same with my cateye el530 using a 500mA micropuck

 

[Matt]

Thanks for the reply I'm hoping to put this in my Cateye 530 also! I've just realised the micropucks I have are 500ma output versions, hence the "SHO" in the part number, this would be over driving the emitter by 150ma, heat/life span might be an issue in the little head of the cateye do you think?

So am I right in thinking I don't need to concern myself with the output voltage of the micropuck to the emitter as long as the ma's are correct?

Having married up the puck to the head it didn't fit where I intended it to, need to rethink its location

 

[znomit]

So am I right in thinking I don't need to concern myself with the output voltage of the micropuck to the emitter as long as the ma's are correct?

Yeah the buckpuck does the hard work and sorts out the right LED current and voltage as long as your input voltage is in the right range.

I think 500mA will be ok. Its around twice the original power. I might use a P7 LED in mine.

 

[Essexman]

Thanks for the reply I'm hoping to put this in my Cateye 530 also! I've just realised the micropucks I have are 500ma output versions, hence the "SHO" in the part number, this would be over driving the emitter by 150ma, heat/life span might be an issue in the little head of the cateye do you think?

So am I right in thinking I don't need to concern myself with the output voltage of the micropuck to the emitter as long as the ma's are correct?

Yes the micropuck will supply 500mA to the LED. The SSC P4 will be fine with 500mA, it won't even get too hot at the current. Bear in mind some guys on here have run SSC P4's up to 1.5A with good heatsinking!


Another idea for you - can you fit one C cell inside instead of the 4AA's ??
The micropuck can be used as a boost driver off one 1.5V/1.2V cell, although you will have less output (as you have less volts), I guess around 200mA to the emitter.

I guess it depends on what you are after, bright or really bright or WOW !

Let us know how you get on.

 

[Matt]

Thanks for your responses chaps, at least I know now it won't go bang when I wire it all up

Ideally I'd like to keep the lamps current configuration with 4xAA's, I've plenty of rechargables for the purpose, I guess I could use one dummy battery to convert it to a 3xAA setup. All the modification being in the removable head, then rebuilt, with no alterations to the main body/battery housing. I'll be taking a mini grinder and cutter to the head this weekend to free up space for the puck (I hope!), I think the full upgrade will cost around £12 and give it a considerable boost in usability, the output at the moment is some what disappointing from a price to light ratio :laughing: