Rechargeable LED Head Torch Repair

Received Rechargeable LED Head Trekking Torch for repair Stating problem of not working. I asked customer when last charged the unit? he replied he kept on charging last night till the morning.
Initial inspection I found no sign of life hence disassembled the unit for further inspection from inside. I suspect battery itself.
First checked Voltages on Battery it is showing 0.9v that is out of the range. So I opened the Battery top to check it looks dry so I added Battery water to both the compartment & using variable power supply.
Kept the battery for charging for 4 hours, then checked voltage, it shows 3.2v so I connected the battery for testing and pushed ON the Switch but still there is no light. Meanwhile I got the Call for one laptop from my nearby area, so kept everything a side & left to attend the call, I come back after two hours & again started troubleshooting on this device. I checked Battery voltage again it shows 1.2v why battery drained too fast? Checked Circuit if shows any short or Leaky component.
Everything seems ok on the circuit. So connected my variable Power supply direct to LED unit & I saw my power supply is loading & display on the power supply goes off indicating some shorting.so I opened LED Head unit it has small PCB with one 6.8Ω resistor on it. Removed the resistor it shows perfect reading. Now removed the LED & checked LED Showing Internal shorting.
Now I come to know why Battery Drained so fast.
Finally, I found the culprit, I did not have this type of led with me I opened my Led Box & found few 1w & 3w Bright LED so I decide to put this LED & see the result.
Identically both LEDs different BAD LED is of Straw Hat type & not sure about the wattage of LED.
Soldered 3W Led it is light up but does not match with reflector. when we turn on Light it out of focus & gives ring effect, so it does not work for the purpose.
Hence Purchased the replacement LED from my part supplier I ask him for wattage he told me I is not aware of wattage but this led is running product, here I do not have any other option so I purchased it. I brought one toy motor also for last time I repaired color stirrer, it broke again from the Solder side terminal. Terminal are very thin & gets broken easily on movement. Again I charged the drained Battery.
After replacing new Led I turned ON the torch…
And it lights up Perfect with proper focus. Fit everything back
& torch is Ready for Pickup.
Sharing wire Connection Diagram also:
This article was prepared for you by Yogesh Panchal who works as a Computer Hardware Engineer in Mumbai India.
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Note: You can check his previous repair articles on Portronics Dash 12 Portable Speakers Repaired- Part 1



Albert van Bemmelen
April 19, 2025 at 5:21 pm
Good job Yogesh. Everything was clear except the working of the on/off push button in the shown circuit.
Yogesh Panchal
April 19, 2025 at 11:09 pm
Thank you! Albert
Soon i will share Article on these special type of switch used in Multi function Torches.
Albert van Bemmelen
April 21, 2025 at 8:29 pm
Understood Yogesh. As I see it here it must be a one pole change-over push button switch to work.
Parasuraman S
April 19, 2025 at 6:31 pm
Very informative and educative article! Thanks for sharing, dear Yogesh Bai!
Yogesh Panchal
April 19, 2025 at 11:10 pm
Thank You! Sir
Mark
April 19, 2025 at 8:24 pm
Well done Yogesh,
Thanks for sharing
Yogesh Panchal
April 19, 2025 at 11:10 pm
Thanks!Mark
erik
April 19, 2025 at 11:40 pm
Br...., an open lead acid battery on your head. Very dangerous.Why not rebuild it with Li-IOn batteries.
Yogesh Panchal
April 21, 2025 at 2:59 pm
Erik,
Thanks!for your suggestion.
I decide Next time i will use 18650 Li-ion Battery though it required to modify the BOX because this Li-Ion Battery will not fit inside.
Waleed Rishmawi
April 20, 2025 at 12:20 am
Well done and thanks for sharing. Have a blessed day
Yogesh Panchal
April 21, 2025 at 3:00 pm
You're Welcome! Waleed
Mark J
April 20, 2025 at 2:42 am
Yogesh, well done on the repair.
Yogesh Panchal
April 21, 2025 at 3:01 pm
Thanks! Mark J
Imoudu
April 21, 2025 at 4:57 am
If I were you,I would prefer to modify it to li-ion battery,in the past I use to replace the acid lead battery but I discovered the replacement doesn't work for more then three months,you did good repair though.
Yogesh Panchal
April 21, 2025 at 3:03 pm
You are right Imoudu,
This lead acid Battery required frequent charging & life span is also very low.next time i will modify it with Li-Ion Battery.