LED lamps powered by an 18650 cell instead of AA

I have such pikachu lights with three LR44 batteries and they shine quite brightly, but the batteries die quickly. So I bought such a USB Type-C module and inserted 550 mAh cells from a disposable e-cigarette and somehow it works. I also have a larger Pikachu, which is about 20 years old, was powered by the mains and had a 12V 10W G4 halogen inside and I replaced it with an Osram 0.9W LED, it also gives 100 lm and I`m thinking about how to power it in an emergency. Three 18650 cells will fit there and I also have a BMS 3S, bought together with the USB-C ones. I`m thinking what`s better, whether to power the 3S and this BMS from a 12V DC power supply like the one for the laptop I have, or to put three in parallel and a step-up converter? And charge from micro USB?

And I went the other way - I removed the battery compartment, connected a long USB cable and between the mains adapter (the so-called phone charger) and the lights there is also a recycled power bank. Due to winter SUP power outages, the Christmas tree is still lit :)



In turn, I obtained power banks from the company`s waste bins for used batteries. Two years ago, the company gave us such devices that were equipped with an illuminated company logo and a shock sensor so sensitive that all we had to do was look harder and the blue backlight was activated. People were annoyed by this and they didn`t use the power banks and eventually started throwing them away. All I had to do was open each of them, remove the backlight and the shock sensor.

Due to the company logo, I will not show the power bank, but I think everyone will be able to imagine it

Thanks for showing the modifications.
Currently, such lamps can be purchased for PLN 4-5, the problem is that they immediately discharge the batteries, which cost much more than the lamps themselves.

I actually replaced the LED flashlight with laser in the "police" flashlight, the magazine for 3xAAA, for 1 pc. 18650. Without any modifications, it has been working for several years, EXTERNAL charging.

I converted all such lamps to USB - I power them from power banks.

chemik_16 wrote:

I converted all such lamps to USB - I power them from power banks

Great, post photos in your free time!

Great solution, I will do the same, but for decorations, e.g. on the table.

PPK wrote:

I actually replaced the LED flashlight with laser in a "police" police flashlight, the magazine for 3xAAA, for 1 pc. 18650. Without any modifications, it has been working for several years, EXTERNAL charging.

This is possible, only in some flashlights where the "magazine" is specially constructed, i.e. slightly longer; these flashlights usually come with a tube for an 18650 cell.
In "normal" 3xAAA flashlights, the "magazine" is slightly shorter than the 18650 cell.
I have both types of flashlights, the photo will explain what I mean:

>>20922042
Nothing to document, USB plug and resistor.

sanfran wrote:

In "normal" 3xAAA flashlights, the "magazine" is slightly shorter than the 18650 cell.

You can always insert 18500. Although at the current price of normal flashlights powered by 18650 and not flashlight-like products, I don`t know if it makes sense.

A BMS would be useful for the cells for their safety and protection against excessive discharge.

operator5wp wrote:

A BMS would be useful for the cells for their safety and protection against excessive discharge.

In my flashlight, the LED starts to glow dimly at a voltage of 2.9-3.1 V.

Piotrek#G wrote:

You can always insert 18500. Although at the current price of normal flashlights powered by 18650 and not flashlight-like products, I don`t know if it makes sense.

I have a Chinese version of something decent - with a charged 18500 and a narrow lens setting, it shines like a decent searchlight. I use a battery with electronics that control the discharge level.