How to make an emergency flashlight

An emergency flashlight with good light and a long operating time will be of great use to both the motorist and the average person at home. In a difficult situation in the absence of electricity, this homemade flashlight will be simply useful. The difference between this design is due to its low cost, which differs several times from purchased analogues.

Will need

Li-ion batteries 18650 - http://alii.pub/5becfz
XL6009 boost converter - http://alii.pub/5bec4w
Protection and charging controller for 4 batteries - http://alii.pub/5kjove
LED headlight - http://alii.pub/5kjp8f
Junction box.
Power supply as a 5-12 V charger.

Diagram of a homemade emergency flashlight

The battery consists of 4 lithium-ion batteries controlled by the controller. The LED headlight is connected to the battery via a switch. The total supply voltage is 14.4 V.
To charge the converter from any low-voltage unit, a boost converter is added, which is configured to boost 17 V.

Making an emergency battery flashlight

Instead of buying 18650 batteries, you can take them out of an old laptop.

We carefully disassemble it, tearing off the conductive tires.
We glue them together with hot glue, leaning opposite sides of polarity against each other.

Wrap with electrical tape. We solder jumpers to connect the batteries in series.

We solder the controller board using double-sided tape and connect it.

We take the junction box and drill holes for the switch and charging connector.

We drill holes in the lid of the box for a lantern and a handle, which can be made from a metal strip of aluminum. We fix everything with screws.

We solder the boost converter between the connector and the charging controller.

We glue the converter and battery to the box with double-sided tape.

Solder the flashlight and switch.

We connect the charging, set the converter to output 17 V.
Close the lid and secure it with screws.

We put heat shrink on the handle and seat it with a lighter.

We put the flashlight on charge.

Now you can check the work.

It shines great.

Considering the battery capacity (3200 mAh) and the power of the flashlight (10 W), the glow will last for 5-6 hours of continuous operation. A huge advantage of this design is that its parameters can be varied as you wish: you can purchase a more or less powerful spotlight, a higher-capacity battery.