DIY 800Wh Battery Pack: Mastering Spot Welding with Copper Connectors

0:00 Full Function Demonstration 1:09 Teardown and modification of 800W pure sine wave UPS, expanding the battery compartment size 4:47 Reassembly of the modified UPS outdoor power chassis 7:50 Installation and fixing of 24V 100W AC charging module 11:36 Reinstall the inverter main board and control board, adjust the original layout 13:05 Assembly of 7P7S 31.5Ah battery pack 21:15 Installation of 50A Bluetooth protection board 27:40 Installation of PD fast charging module 30:00 Complete machine display and 800W power burn-in test For this DIY outdoor power supply project, I built a brand-new portable power station with a decommissioned UPS chassis, suitable for camping, fishing and emergency backup power scenarios. I adopted a 31Ah 24V ternary lithium battery, abandoning bulky LiFePO4 batteries and traditional lead-acid batteries, which makes the unit lighter and the structure more compact. The unit is equipped with a built-in mains charging module, eliminating the need for a heavy external charger. It features a rich range of ports: PD 3.0 Type-C output, standard USB-A output, a top-mounted wireless charging module, a 24V DC direct output port, and an 800W AC mains socket. Direct power supply for DC appliances is more power-saving and efficient. The total cost of all components is kept within $100. Parts Cost Breakdown: 49pcs 21700 battery cells: approx. $64.29 Decommissioned UPS chassis from computer rooms: $0 Copper busbars, wires, terminals, Anderson connectors and main power switch: approx. $21.43 PD fast charging module: approx. $7.14 Wireless charging module: approx. $7.14