Lesson 2.1 — Panels, Batteries, Controllers, Inverters
Four components make an off-grid system. The panel harvests. The charge controller protects the battery — PWM (cheap, panel voltage must match battery) or MPPT (10–30% more harvest, flexible voltages). The battery stores — flooded lead-acid (cheap, needs water top-ups), AGM (sealed), or LiFePO4 (lighter, 80–90% usable, longer life, needs a BMS). The inverter converts to 230 V AC — pure sine wave for motors, fridges and electronics; modified sine only for simple resistive loads.
Key points
- MPPT harvests 10–30% more than PWM
- Pure sine inverter for anything with a motor or electronics
- LiFePO4: more usable capacity and cycles than lead-acid
- Match controller amp rating to panel Isc × 1.25