New project started again, one by one, endless.... This one is a 3S 18650 battery pack for QRP radio operation. I would like to build a compact rechargeable battery pack that can provide a practical field power source for small HF/VHF QRP radios. The pack uses three 18650 lithium cells in series, giving a full-charge voltage of about 12.6 V, which matches the external DC input range of many portable radios. The target output is 12.6 V / 5 A max, enough for most QRP transceivers during receive and moderate-power transmit operation. It is intended for radios such as FT-817/818-style portable rigs, IC-705-type setups with suitable input limits, small CW transceivers, and other field radios that can accept a 3S lithium pack voltage. The board includes the battery holder, protection circuit, charging input, power switching, status indication, and output connector area in one module. T Main design goals: - 3S 18650 battery pack - 12.6 V fully charged output - 5 A maximum output target - Suitable for QRP radio field operation - Built-in protection and charging circuit - Compact PCB module - Clear power and charge indicators - Practical output connector for radio useNew project started again, one by one, endless.... This one is a 3S 18650 battery pack for QRP radio operation. I would like to build a compact rechargeable battery pack that can provide a practical field power source for small HF/VHF QRP radios. The pack uses three 18650 lithium cells in series, giving a full-charge voltage of about 12.6 V, which matches the external DC input range of many portable radios. The target output is 12.6 V / 5 A max, enough for most QRP transceivers during receive and moderate-power transmit operation. It is intended for radios such as FT-817/818-style portable rigs, IC-705-type setups with suitable input limits, small CW transceivers, and other field radios that can accept a 3S lithium pack voltage. The board includes the battery holder, protection circuit, charging input, power switching, status indication, and output connector area in one module. T Main design goals:New project started again, one by one, endless.... This one is a 3S 18650 battery pack for QRP radio operation. I would like to build a compact rechargeable battery pack that can provide a practical field power source for small HF/VHF QRP radios. The pack uses three 18650 lithium cells in series, giving a full-charge voltage of about 12.6 V, which matches the external DC input range of many portable radios. The target output is 12.6 V / 5 A max, enough for most QRP transceivers during receive and moderate-power transmit operation. It is intended for radios such as FT-817/818-style portable rigs, IC-705-type setups with suitable input limits, small CW transceivers, and other field radios that can accept a 3S lithium pack voltage. The board includes the battery holder, protection circuit, charging input, power switching, status indication, and output connector area in one module. Main design goals: - 3S 18650 battery pack - 12.6 V fully charged output - 5 A maximum output target - Suitable for QRP radio field operation - Built-in protection and charging circuit - Compact PCB module - Clear power and charge indicators - Practical output connector for radio use - 3S 18650 battery pack - 12.6 V fully charged output - 5 A maximum output target - Suitable for QRP radio field operation - Built-in protection and charging circuit - Compact PCB module - Clear power and charge indicators - Practical output connector for radio use