The completed solar panel testing shunt regulator.

I designed the Solar Panel Testing Shunt Regulator to function as a variable voltage shunt regulator for measuring the power output of small solar panels.

I wanted to be able to load the output of a solar panel with a variable load to obtain various output voltage levels and measure the corresponding current flow. Repeating current measurements at various voltage levels to characterize a solar panel without having the output voltage level drift.


Inside view of the completed solar panel testing shunt regulator.

The shunt regulator has a two position range switch. A high range where the shunt regulator starts to conduct at about 28 volts at the minimum shunt setting and a low range that the shunt regulator starts to conduct at about 15 volts with the minimum shunt setting.

Both ranges can shunt the solar panel to less than about 1 volt at the maximum shunt setting but the low range has a finer voltage adjustment.

Here are the measured voltage levels at full shunt and the corresponding current levels for this unit.

.25 volt @   500 ma.
.44 volt @ 1055 ma.
.74 volt @ 1750 ma.


Side and inside view of the completed solar panel testing shunt regulator.

Digital meters and solar shunt regulator.
Heat sink and inside view of the completed solar panel testing shunt regulator.


Solar Panel Testing Shunt Regulator
Schematic, Board Drawing and Parts List.

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