Quote:
Originally Posted by Sailorman Ed
I understand how a 110v charger tapers off when the LiPO4 battery is full but how does it work with a solar controller? The solar panel is still putting out power. How does the MPPT controller handle this? What happens to the solar panel amps when the battery is full? It doesn't hurt the panel to do nothing under full sun?
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Only one person actually answered the question.
See the attachment below for a typical solar panel power-voltage curve. The
power output by a panel will depend on the voltage that it is held at. For example, if you attached that panel to a 12V battery directly (hence holding it at 12V), it will be well down its curve and will only produce ~150W.
In normal operation, the
MPPT controllers will vary the voltage up and down to find the highest power output point (i.e. the peak of that curve). When the battery is full (or nearing full) and less power is required, the MPPT controller will increase the voltage past the MPP, which will reduce the amount of power the panel is making (i.e. pushing further to the right on the curve). When no power is demanded, the MPPT allows the panel to go open circuit. In this circumstance it will be at its maximum possible voltage, but zero
current, so zero power.
Panels are ok with being run like this.