A Dual‑Battery Load Sharing System supplies a DC load from two batteries in parallel (or main + backup) while preventing reverse current and over‑discharge. Using ideal‑diode OR‑ing (MOSFETs) or power diodes, plus a current‑share controller, the system automatically balances current, prioritizes the healthier/primary battery, and seamlessly hands over to the backup if voltage drops. It’s perfect for solar + grid/alternator hybrids, robotics, UPS carts, e‑bikes, and field instruments where uninterrupted power is critical.

Parts Used:

1. Batteries (2x) – Lead‑acid / Li‑ion / LiFePO₄ packs (with individual BMS for lithium)
2. Ideal‑Diode OR‑ing Modules (Back‑to‑Back MOSFETs) or Schottky Diodes
3. Current‑Share / Balancer Controller (active current balancing IC or DC bus shunt + MCU)
4. DC Bus Shunt(s) / Hall Current Sensors – for current measurement & protection
5. DC‑DC Converter (buck/boost) – regulated output to the load
6. Charge Sources (optional) – Solar charge controller / Alternator / AC charger
7. Protection – Input fuses, TVS diode, reverse‑polarity & over‑current protection
8. Relay/Solid‑State Switch (optional) – priority selection or maintenance isolate
9. Wiring, Busbars, Connectors – low‑resistance interconnects; voltmeter/ammeter display