Modding a flashlight driver for wider Vin ranges??

Another long time listener, first time caller here. Usually I can find precisely the information I need without asking, but this time I am stuck.

Is there a straight-forward way of modifying a say, 17mm driver to accept a wider range of input voltage like perhaps 9-32VDC?

The reason I ask is that I have a very specific automotive application in which a 17mm-20mm driver would fit perfectly in the space I have, but it seems they have a rather narrow range of Vin, and I would be looking to power the driver off of a 12v vehicle battery. I have been told that automotive power systems can be “dirty” or “noisy” and would likely burn up the driver quickly.

I am fairly competent at soldering, so if this could be as simple as buying a driver and swapping out some components, it would be worth a try.

Any help would be appreciated!!!

A little more detail:

–12v motorcycle battery, stator charged
-looking at single XHP35, single XP-G3, single XP-G2, 3-up XP-G2
-individual drivers for each configuration
-dimming not necessary

Or, could anybody please point me to a thread that contains this information? I’m not looking for a free meal, rather, it appears I just do not know how to phrase my search in order to produce relevant results.


When a driver is designed the input voltages are taken in to account for every single component on the driver such as ic’s and capacitors. Resistors have to be power rated.
If you double the input voltage theoretically, you would need twice the power rating of a resistor for it to work properly, depends on the design.
Most of the time components are selected above what the actual rating needs to be. A little overhead is built in to ensure proper operation under varrying conditions because sometimes ratings are inflated from manufactures.
A driver that’s designed to work with a input voltage of 4.2v max can probably with stand a input voltage or 4.5v or so but when you push the voltage even higher, the magic smoke will soon follow. Some drivers are being run right on the edge of destruction in the first place, so adding more voltage may cause failure pretty quick.
You’ll need to find a driver that’s made for your input voltage.
I thought this driver used by Mrsdnf was pretty interesting.

The seller has a few on ebay that might work for you. They seem to have a few different settable options.

I know you are tight in space due to “specific automotive applications” but I’m just curious why not do something what car automotive LED drivers do? An external ballast/driver and leaving just the LEDs in the host? It’s way easier than jamming everything in small place and gets all heated up together.

If that is possible you can get any buck dc-dc stepdown regulators since you don’t need dimming. Slap it in some waterproof container and run wires out. Since most DC-DC buck drivers work off 9-30v DC at 5A it should be sufficient even for dual XHP70.2 without overheating.

Without description I’m just assuming you’re doing a retrofit for a motorcycle headlamp. So there are bound to be space if you do not jam all inside a 17mm package.

Thanks for the reply! That is likely what I will end up doing. I was hoping to produce something self-contained, but it will likely be more headache than it is worth.

I think I will get back on track with what you proposed.

Thanks again!