"How to make a special battery charger"

     Parts needed   https://www.ebay.com/itm/red-black-test-clamps-meter-battery-charger-clamps-copper-spring-CLAMPS/273945791784 https://www.ebay.com/itm/1-2-3M-2-Core-Vintage-Twist-Braided-Fabric-Light-Lamp-Cable-Electric-Wire-Cord/133048607233?var=432347664463 https://www.ebay.com/itm/12-24V-Charge-Control-Module-Storage-Lithium-Battery-Protection-Board-XH-M603/182502866102 https://www.ebay.com/itm/AC-DC-12V-2A-Buck-Converter-Step-Down-Isolation-Supply-Regulator-Power-Module/322073579191 https://www.ebay.com/itm/2-Prong-Electrical-Plug-Black-rubber-shell-polarized-male-plug-connector/112608325602 https://www.ebay.com/itm/2-Pin-Extension-Wire-Cord-12-22AWG-Black-Red-Soft-Silicone-Electrical-cable-line/223580996150?var=522355802864 https://www.ebay.com/itm/228pcs-Personal-Computer-Screws-Standoffs-Set-Assortment-Kit-for-Mother-B-S4L6/113049800409 https://www.ebay.com/itm/228pcs-Personal-Computer-Screws-Standoffs-Set-Assortment-Kit-for-Mother-B-S4L6/113049800409 https://www.ebay.com/itm/2-Pcs-125V-6A-On-On-2-Way-SPDT-3-Terminals-Toggle-Switch-Car-Dash-Metal-12V/332159521261 https://www.ebay.com/itm/Adjustable-DC-DC-Power-Supply-Buck-Converter-Step-down-Voltage-Module-DC-6V-32V/142476764473 ...