We make a mini Power Bank for an honest 3400 mAh from a syringe and an 18650 battery

When buying inexpensive power banks, you probably noticed that its actual volume is absolutely not true. Often the manufacturer claims 10,000 mAh, when in reality the actual capacity is 2-3 times less. At the same time, such a power bank is quite bulky. We suggest how you can make a drive with an honest 3400 mAh capacity that easily fits in the palm of your hand.

Materials:

Syringe 20 cc;
battery NCR18650B 3400 mAh 3.7 V - http://alii.pub/5ylao5
mini power bank charging module 5 V - http://alii.pub/5ylaku
sheet plastic.

Power bank manufacturing process

The rod with the piston is removed from the syringe, and the nose is cut off.

Then you need to cut off the finger stops.

After this you need to get rid of the scale. It can be washed off with solvent.

The case contains a battery and a charging module for testing. The length of the syringe is adjusted to their joint length.

Then you need to solder the module to the battery. To do this, you need to cut off the insulation on it in the place with a mark in the form of a black stripe, and tin the contact.

Next you need to tin the module and solder it to the battery.

A wire jumper is used to connect the side contacts.Then, to add rigidity, everything is additionally fixed with hot glue.

Now you need to work on the plug for the housing. You can cut out its template from paper, and use it to make a plastic part.

Holes are immediately cut in the plug for access to the connectors, after which it is glued in place.

The resulting power bank is compact in size.

Moreover, if you buy parts for it from Aliexpress, it will turn out quite inexpensively. In the future, it can always be disassembled to replace the battery when it fails.