In hindsight I'm thinking that there is possibly a risk that if the LEDs in the tap point for the charger circuit fail open circuit, then when the cell is charged and the charge chip tries to break the current flow then it will be potentially exposed to hundreds of volts and could fail, potentially letting the lithium cell continue charging until it too fails in a very overcharged state....
I have to admit that this is a very clever idea. It's a standard LED lamp with the addition of a lithium cell. In normal use it charges from the mains while lit, but in the event of power failure it will light up automatically, but only if the wall switch controlling that light is on. That basically means you can turn it on and off from the light switch even when there's a power cut. It does this by applying a small DC voltage to the lamps contacts and detecting if it is bridged. If the wall switch is off then no significant current will flow, but if it is on then current will flow through other appliances and circuits in the house and it will detect that and light.
This does mean that it can only really be used in a single lamp holder on its own, and the switch can only be a simple one with no active electronics.
My apologies for all the random noises. I filmed this at work and there were explosions and gunshots in the background. Some lights on part of the show also needed their positioning adjusted slightly, so there was some loud walkie talkie use too because I had the volume up quite high. (It's a very loud show.)
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm

15 thoughts on “Inside an intelligent emergency lamp with schematic.”
  1. Avataaar/Circle Created with python_avatars Eye Ford says:

    SO, to charge the battery, the light needs to be kept on, correct?

  2. Avataaar/Circle Created with python_avatars Aung Myo Khaing says:

    If this circuit add overcharging circuit for battery, can a risk in these circuit?

  3. Avataaar/Circle Created with python_avatars Nature Connections says:

    led rechargeable bulb remains on even if switch is off. Which part needs to be replaced in the circuit?

  4. Avataaar/Circle Created with python_avatars DoctorX17 says:

    I saw these and was thinking about getting a few, but realized that I don't really have a use for them… power outages in my area are exceedingly rare, and when there are power issues, it's usually on the order of seconds or minutes; worst case I can think of was hours, and I have a plethora of flashlights and battery banks around, so these would probably just sit and the 18650s would eventually die from being topped off all the time and not work when I need them to in 4-5 years, lol

  5. Avataaar/Circle Created with python_avatars sadfreewee says:

    I want to make my own emergency lamp using a TP4056 lithium battery charger. Any ideas on how to use the circuit to switch on you described with that module?

  6. Avataaar/Circle Created with python_avatars Atul Shinde says:

    Does this bulb has switch to turn from battery circuit to direct electricity circuit when electricity is their or its runs from charging circuit.

  7. Avataaar/Circle Created with python_avatars Dinuka Thelis says:

    Great explanation and it's working properly..Great work✌

  8. Avataaar/Circle Created with python_avatars Ruwan Leelananda says:

    thanks, very good 👍

  9. Avataaar/Circle Created with python_avatars Nash says:

    Please can you help me make a Gerber file for it?

  10. Avataaar/Circle Created with python_avatars Jaco Annandale says:

    Hi there Clive.
    What can be wrong if the light doesn't turn off when no ac power is applied?

  11. Avataaar/Circle Created with python_avatars Sahan Ruwinda says:

    Can you send me a clear diagram with right components

  12. Avataaar/Circle Created with python_avatars Brian Jeshanthan says:

    It is a zener diode to reduce the voltage

  13. Avataaar/Circle Created with python_avatars CESAR HERNANDEZ says:

    por favor donde desscargo el esquema?

  14. Avataaar/Circle Created with python_avatars Agus Nurcahyono says:

    Thankyou for the explanation sir

  15. Avataaar/Circle Created with python_avatars Julio Navas says:

    What is the max impedance or resistance of the "lights out" path the bulb could work with?

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