This charger, 20A 1-8S balance charger: https://www.amazon.com/ISDT-Touchscreen-Battery-Charger-Discharger/dp/B0823DGJXS?th=1 8S balance leads (no, you don't need 10, and you'd only use 5 of the 9 wires for 4S): https://www.amazon.com/JST-XH-Balance-Extention-RC-Battery/dp/B085W1T31S?th=1...
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