Custom 17mm 5Amp PWM-less linear driver-preliminary

I just noticed: in your op it says “5 amps default” how high can this thing go? >)

Heat is limitation((Vbatt-VLED)*I),but 6Amps wouldn't be problem for single xm-l2 because of high Vf.

What modes are you currently planning?

(sorry if I missed it somewhere)


At that price I will take 5, as long as HKJ’s test will turn out right. :wink:
As this is a single cell / single emitter driver, a small loss in the driver is crucial, imho. Otherwise 5A with an XM-L2 won’t last long with usual protected cells like Panasonic 3400 or Sanyo 2600. I got my fingers crossed.

Happy to see a EU-offer. No hassle with customs and import-VAT :slight_smile:

I ran a few different cells directly to an XM-L2 mounted on a copper pill to test Direct Drive numbers for an idea of where the top end is for today’s high discharge cells. This is, of course, what this particular emitter did on my pairs of cells…

Sony VTC4………7.10, 7.18A
Sony VTC5………6.73, 6.89A
Samsung 20R……6.63, 7.03A
Samsung 25R……6.68, 6.71A
Efest 35A…………6.85, 7.04A
Panasonic PF……6.14, 6.04A

These were all rested at 4.19-4.20V

I'm a huge fan of pertinent information :-) . Those are useful numbers!

I will be waiting for this driver to be released. :slight_smile:

I’m in for 5. Subscribed

This looks promising.

I assume you are writing the firmware so would you be prepared to take suggestions for UI ‘features’?

How about Zebralight’s UI mode?

There are many modes and easily can be selected by just tail clicking.

Battery checker, sub mode changeable and so on…

Perfect driver for this DIY drop-in. I decided to wait for this driver to be released.

Metalmania, what is that P-60 host. Is that one of Mattaus’s?

interesting. Subscribed.
I would love to see a good compact driver like this that can drive an MTG2 from a 12V NiMh battery pack (~14V charged I think)

The drop is solarforce specific. I made it according to Solarforce P1D inner dimension. If you are asking about the glossy red object on the top right side of the picture, that would be a Fivemega Elephant 2. Belongs to a friend. :slight_smile:

Hi Led4power, progress on this? You are killing me with the silence! :D

I hear this more often.
But wouldn’t that be solved with a 47µF (maybe 22 or 10 would do) capacitor parallel on the LED, smoothening the lot to its average?

I think it might take a prohibitively large capacitor to do this but you’re welcome to try it and let us know.

For 50 or 60 Hz you need plenty of µF.
But of course this halves when you double the frequency, and halves again if you double it again.
It depends on the PWM frequency and current drawn.

It is not my expertise, but from what I remember, people have thought about it and came up with capacitors that were way too large for a flashlight. Only 'supercaps' were small enough with enough capacity but they suffer from other problems, like limited cycle life, and charging/discharging times that were not fast enough.

Well, there is this ‘rule’ I forgot, tells you approximately how much capacity you need to (more or less) eliminate the ripple.
Something like 1000µF for every Ampere drawn, at 50 Hz (probly 20% less needed for 60 Hz).
5A is quite a lot though…
But tantalum caps are very small and fast too.
(aren’t they?)