Every off-grid (battery-based) renewable energy system requires a charge controller. A solar charge controller keeps your batteries from overcharging by opening the circuit between the batteries and the solar PV array when it senses the battery voltage reaches a set point. As battery voltage drops, the solar charge controller turns back on, ready to defend your batteries again – and greatly increasing their lives. A wind or hydro charge controller works much the same, except instead of opening the circuit, it diverts excess power to another load (called a diversion load).
Real Goods offers off-grid charge controllers with the latest technologies like pulse width modulation (PWM controllers) and maximum power point tracking (MPPT charge controllers) from top brands like OutBack, Morningstar, MidNite, and more.