Measure your project
Designing and assembling your own solar projects can be fun, educating and even profitable. But how can you keep track of your solar output. It might be very handy to get some stuff that keeps track of your actual PV-panel output and you battery charge. When set-ups get bigger usually the charge controller can show you this information, but just in case we’ll introduce some gadgets.
A small panelmeter can show you the battery-level and voltage in one quick view, just put it somewhere easy accessable. Meters like this are available in many variations and voltages depending on your set-up.
Measure the PV-panel output
It’s easy to measure the output voltage of your panels with a multi meter, but to measure the current you would have to interrupt the line from the panels to the controller. Luckily special double meters are available.
The installation of the combined volt- and ampere-meter is a bit more complicated. One of the lines from the panel to the charger has to be interrupted to put the shunt in. The shunt will be able to handle large amounts of current, depending on the shunt size upto 200 Amps, but in most cases 0-50A seems adecuate.
The function of this is easy. The shunt is just a “resistor”, the more current that flows through it, the more voltage wil be measured by the panelmeter on the shunt. Most shunts are 75mV (milliVolt) so it influences the yield hardly.
In a working set-up the controller just shows the batteries are over 75% charged, but on the meter we can read that the panel output is 29.4V (24V set-up)and 9.6A current is going to the batteries.
Schematics on how-to connect these meters can be found in the PDF
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