MK4+ Hybrid Charge Controller User Manual
2
2. Performance Description
PWM Stepless Load-Dump Mode:
When a wind generator system is producing more power than the battery can
accept, most typical marine wind generator systems simply hit a set-point, and
divert all of their energy to a resistive load, and the battery stops charging
completely.
These crude systems haven’t changed since the 70s, and simply
consist of a voltage-sensi
tive switch and a resistive “diversion load”.
However, when using such a system, the battery never really gets a full charge;
leaving the battery in a partial state-of-charge (PSOC), which is horrible for
battery life. While the battery itself still could have accepted some of that
available power (and reached a full state-of-charge), it was instead wasted
completely. Even with a staged load-dump system, where there are multiple
resistive elements switched sequentially, it can only be divided into five to six
stages, so the effect is still some PSOC. The MK4+ charge controller uses
Pulse Width Modulation (PWM) to create a step-less load-dump mode. In other
words, the controller can dump residual power by dividing it into thousands of
stages. So, it can still dump residual or excess power while effectively
charging battery banks to a full state-of-charge. Charging batteries to their
maximum capacity maintains their overall charge capacity and significantly
preserves battery life.
