- 3 -
controller judges that the battery is full and goes straight to the floating charge. If the battery voltage
is lower than the “ascension back charge voltage”, the charging process should be MPPT,
(equalizing charge), improving charge and floating charge. And a improving charge happens during
every charge. Charging curve as follows:
Picture 3 Charging curve
A. MPPT charge
The stage for rapid charging.
The controller will be MPPT charging to provide the biggest solar power to the battery till the
battery charging voltage is up to “ascension back charge voltage”. When the battery voltage reaches
improving charge voltage, controller turns to improving charge.
B. Improving charge
When the battery voltage reaches improving charging voltage, the controller will be converted to
constant voltage charging mode. In this process, the controller will not be MPPT charging and the
charging current will decline gradually over time. Under the condition of improving charge time up
to the set time (1, 2, 3 hours), the controller will convert into floating charge. And when the battery
voltage is less than “ascension back charge voltage”, the controller will be improving charge again.
C. Floating charge
Controller will be improving charge again. When improving charge is finished, the controller will
reduce the charging current in order to reduce the battery voltage and keep it matched with the
floating charge voltage. During Floating charge stage, there is very weak battery charging, which can