I have one 200w 24v panel reading 40v at the bare wire ends before connecting to the mppt. When I securely connect the wires to the mppt and check the voltage at the connection point, I get a reading of .7v does anyone know why this is happening?
asked
100/20 solar connection problem
It might be that the MPPT is clamping down the input- do you have a battery connected? You can use VictronConnect to connect to the MPPT, that might also shed more light on why it does that
@Aaa247, either your PV voltage is reversed or you have a bad MC4 connector. An improperly crimped/connected MC4 connector may show voltage but that will drop to 0v or thereabouts when a load is applied in an attempt to draw current through it.
Thanks Justin, I will check for reversed voltage but how do I check for a bad mc4 connecto?
@Aaa247, glad to hear you got it worked out; to answer your question just for future reference, though, the easiest way to check for a bad MC4 connector is with an IR cam (available pretty cheaply as an attachment for smartphones) or with a handheld non-contact IR thermometer - you can usually pick those up for $20 or so. A bad connection in a DC system, whether in an MC4 connector, a crimp, a loose bolt/nut, or a bad component, will generate heat... so it's relatively simple to work along a line of connections and just look for anything that seems unusually warm. A hot connection is a bad connection!
It was reversed. Thank you guys for all your help and recommendation!
