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Hi everyone ... I thought that when I put a tarp over the panels and some weights to hold it in place that I would not measure any PV at the MPPT, however, it's still almost full strength. Am I misunderstanding PV here or is there potentially something wrong? TYIA!
Without a load it takes surprisingly little light to get a voltage on the panel. Are you measuring the voltage open circuit, or is the voltage being measured by the MPPT? Maybe your tarp isn't opaque enough. You could check the charge current with the tarp on and the system hooked up. You'll probably see a low, but non-zero charging current if the tarp is just letting too much light through. Check the voltage at night and see if it's much lower as you would expect.
Disconnect the wires and measure the voltage on the PV and also the MPPT terminals. Open Circuit Voltage with essentially 0 amps is not "full strength". As soon as you apply a load to the PV wire, then you will see the voltage drop towards zero volts.
Do not disconnect the panels while you have voltage. It will cause arcing, damage connections.
When the MPPT draws a load, voltage at panels drops rapidly. Net result is that in optimising power output, MPPT reduces panel voltage, but not by a huge amount. So think of it in separate parts. A part to maximise power from panels and a part to apply a charge curve to the batteries by dropping the voltage and controlling charge current.
