Making a super bright rechargeable LED flashlight with your own hands

In my article, I will tell you how to make an insanely bright rechargeable LED flashlight and turn night into day with your own hands.

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Most of us use flashlights when hiking, for night walks, or simply when going out into the dark. We usually buy these lights at hardware stores, and they shine quite dimly. To fix this, I designed and built a heavy-duty flashlight that is suitable for illuminating the road at night, creating cool photo and video effects (like glowing spheres in science fiction), illuminating a work site and much more, all at a reasonable cost.

How the device works

The LED flashlight works on the principle usual for such devices:

the battery is charged from a regular 220 V network;
as an option, you can use a special charging micromodule from the USB connector of a laptop or computer;
Power is supplied to the LEDs using the “off/on” button;
to ensure normal supply mode, a current-limiting resistor with a nominal value of 3 Ohms is used;
The LED matrix receives the necessary voltage and begins to emit light.

The option using a microcharging module seems to be more successful. The device functions as a charge controller and prevents excess energy accumulation. In addition, the dimensions of this module allow it to be installed in a small housing, which is important in the manufacture of compact devices. The presence of a micro USB connector allows you to use a separate cord, which is inserted only during charging.

Attention! Standard LED lights are powered by 12 volt batteries, which increases the charging time and requires a 220 V network. The do-it-yourself option allows you to use a battery from a smartphone or mobile phone, and you can charge it in the field from the USB socket of a laptop.

What kind of LEDs are used in high-power flashlights?

Powerful flashlights mean modern flashlights of various types, ranging from those the size of a finger to huge search flashlights.

In such products, the Cree brand is relevant in 2022. This is the name of an American company. Its products are considered one of the most advanced in the field of LED technology. An alternative is LED from the manufacturer Luminus.

Such things are significantly superior to LEDs from Chinese lanterns.

What Cree LEDs are most commonly installed in flashlights?

Models are called consisting of three or four characters, separated by a hyphen. So diodes Cree XR-E, XR-G, XM-L, XP-E. Models XP-E2, G2 are most often used for small flashlights, while XM-L and L2 are very versatile.

They are used starting from the so-called. EDC flashlights (everyday carry) range from small flashlights smaller than the palm of your hand to large, serious search flashlights.

Let's look at the characteristics of high-power LEDs for flashlights.

Name	Cree XM-L T6	Cree XM-L2	Cree XP-G2	Cree XR-E
Photo
U, V	2,9	2,85	2,8	3,3
I, mA	700	700	350	350
P, W	2	2	1	1
Operating temperature, °C	Flashlight repair

Unfortunately, the price of such flashlights is quite high, as are the diodes themselves. And it is not always possible to purchase a new flashlight in case of a breakdown. Let's figure out how to change the LED in a flashlight.

To repair a flashlight, you need a minimum set of tools:

To get to the light source you need to unscrew the head of the flashlight; it is usually attached to a threaded connection.

Chargers for 18650 batteries

For battery

18650 will have to use the correct charger. At the output it will produce 5 Volts and a current from 0.5 to 1 of the rated capacity of the battery itself. If lithium cells support 2600 mAh, then a current of 1.3-2.6 amperes should be used to charge it.

Lithium battery

The battery is charged in several stages:

First, a voltage of 0.2-1A is applied to the battery
.
Then charging
takes place at a constant voltage.

If the charger has a pulse

mode, this will significantly speed up the charging time.

If the battery contains graphite,

then the voltage should not exceed 4.3 Volts per element. If you exceed this figure, the energy density will increase and the oxidation process will begin.

There are lithium batteries

charging in less than an hour. They do not provide for the second stage - the current is immediately supplied to 80% and after that it is put into operation. This is normal for a lithium battery.

Main conclusions

To create an LED flashlight with your own hands, you will need to prepare a set of elements, the main ones of which are:

3.7 V battery;
micro charging module;
cap with lens and LED.

The assembly procedure is not particularly difficult. You will need at least basic skill in using a soldering iron and other tools. The result is a very high-quality and efficient LED flashlight. Please provide your clarifications and options in the comments.

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