I have a MPPT 100/30 Smart Solar charge controller. I tested the panel and connected it and it worked fine. I then disconnected it so I could mount it on the vehicle roof. After mounting it and reconnecting the panel to the charge controller, it only shows low voltage varying between 2-13v no higher I have tested all the wiring and connections the whole way from the panel through and it’s always showing 16v or greater depending on where the sun is. But as soon as I screw into the terminals in the controller the voltage drops back below 13v.
Picture of the solar display when I tested the panel before mounting and now currently.
Straight line from the 250w panel on roof to anderson plug connection on back of 12v system box, straight from that anderson into the solar controller. Have taken readings at solar panel,anderson connection and wire ends before going into controller all well above 18v but as soon as connected to controller terminals, shows a massive drop.
It looks like a metal frame, the devices are mounted to, right?
What is the voltage reading when u use a voltmeter on the screw terminals?
Does the readings of the mppt and voltmeter correspond?
Just unscrew/isolate the mppt from the mounting surface and check whats happens.
BTW: 16V is not enough, the voltage of the panels must be at least 5V above Battery voltage for the MPPT to start.
In general a significant voltage drop of the panels is to be expected, because that‘s the way MPPTs are working. They are shifting voltage/current to the point where the power is maxed out.
What are the specs of your panel? Do you have two identical panels to use them in series to double the voltage?
