USB powered li-Ion charger for 18650 battery

It's a basic holder for 18650 batteries.
The charging circuit is based on the TP4056 chip, different models exist, take the cheapest.
Search for "TP4056 USB Li-ION Battery Charger" to find a provider on the net.
Spring was retrieved from an old battery holder. There is a small slot to hold and block the spring.
For the positive side, strip the cable on 2/3 cm, make a small ball with the wires, put solder on it and press on the plastic when hot.
The.scad file is available if you want to cha