Night Buddy style headlamp teardown with schematic

Описание: Everyone has their own preferences for an LED head torch. Mine is for a focussed beam to point light at a good position for working, but others prefer a wider wash of light. The flexible COB strip is an interesting twist. Other versions seem to have a second circuit with red LEDs for maintaining night vision.
I regard head torches as being essential for power outages as it's much more useful to light what you're looking at instead of trying to light a whole room.

The circuitry in this light isn't too bad. It's fairly textbook, with a minimal design. My only slight concern is the position of the solder pads for the infrared detection. They are close to the surface of the pouch cell, although they've cropped them short before soldering, so the wires don't protrude much.
I've since been sent a picture showing that the solder points can indeed pierce the lithium cell, but in that case it just caused electrolyte leakage corrosion and didn't go far enough to cause a short circuit in the cell.

I measured the LED current directly powered at 100% at 4.2V (full charge) and 3V (discharged).
Main COB strip @4.2V = 1130mA @3V = 280mA
Focussed beam @4.2V = 487mA @3V = 107mA

Standby current is too low to measure, but the lack of resistors in series with the status indicator LEDs means they are being driven at 20mA each! They could really have done with a 1K resistor in series with each LED. That also means that when in infrared standby with both LEDs lit the total current is 70mA of which the majority is the red and green status LEDs.

During use the lights will start bright, but as the lithium cell discharges the intensity and current will decrease, giving a decent run time.

I use a head torch at work a lot, and tend to use it at the lowest intensity that still allows comfortable working, to get the maximum run time between charges.

These lights can be found on eBay by searching for either:-
All perspectives induction headlamp
or
night buddy headlamp
The cost should be around £$€10.

Alternatively you can buy the heavily marketed version for around three times that price.


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