Troubleshooting Solar Panels

Video Transcript
If you don’t think you’re getting the right amount of power from your solar panels, or you’re getting no power at all, I’m gonna go over a couple of different tests in order to make sure your panels are operating correctly. This is Mike with RPS Solar Pumps. While this is gonna apply directly to our panels, it also applies to all solar panels on the market. I’ll show you a couple of tests and things to look out for when setting up your panels to make sure they’re operating correctly. By far the most common cause of low power output of your solar panel is an obstruction or other shadow on your array. The way most solar panels are wired are that all the cells are wired in series. So here we have a little edge corner protector that comes for shipping on our panel. We want to make sure these are all removed. Right here it’s blocking about 25% of one of the cells this will actually current limit all of the other cells are in series so blocking 25% of one cell can cause a loss of around 25 percent of power across the entire array so for this hundred watt panel it’s only gonna help put around 75 watts so we want to make sure any corner protectors are removed and make sure there’s no shadows on it we have a great video about shadowing and cleaning your panels linked in the description below this shows real-time power output in how a small shadow affects output of the entire solar array okay so you removed all the obstructions or any shadows on your array and you still either aren’t getting any power or you’re getting low power for this I’m gonna go over the other tests we want to perform you want to do these tests on nice sunny days it’s gonna make troubleshooting much easier as you can see here we have our panel and full Sun on it you’re gonna need a multimeter for some of these tests one like this is harder to do current but also does the voltage measurements very well I prefer a multimeter like this this is a clamp-on style multimeter we can clamp this over our wire in order to measure current plus we can test voltages using our two probes I’m gonna go over a couple of those measurements right now with the panel the first measurement we want to do is just called open circuit voltage of our solar panel that is the voltage that the solar panel is putting out under no it’s called VOC or voltage open circuit so we’re going to take our multimeter here and we’re gonna set it to v4 volts in this case it defaults to AC voltage we’re going to use the function button and switch it over to DC volts from here we can take our probes and we can put them down into our mc4 connectors in order to make contact with the terminals it really doesn’t matter which one we connect to which will either get a positive or negative voltage depending on which one we connect in here you can see full Sun we’re getting 21.5 volts that’s a good reading for this type of panel on the back you’ll see specs of all your panels so you should be able to match up the measurement vo see that we’re getting here to the spec on the back your panel to make sure it’s outputting the right voltage you’re getting a strange low voltage and you’re in full Sun and there’s no shadows on it that can be a sign of electrical connection problem I’m going to go over what things to look for when you think you might have an electrical connection problem so that is our voltage measurement called vo C voltage open circuit the next measurement we’re gonna do is our current measurement that’s also called ISC that’s current short-circuit what we’re gonna do is we’re gonna short the two connections together and then do a current measurement with our clamp on meter in order to detect what short-circuit current we have again this spec should be on the back of your panel for this hundred watt panel we’re looking for right around 5 amps or so so I’m going to take my meter again and this time I’m gonna set it to a 4 amps it also might say Aye which stands for current usually there’s a couple of different ranges when they use the lower range which is 60 / 600 amps I don’t need to use the thousand amp we won’t be that high so again it defaults to AC and for this specific meter I need to push the function button to bring it to DC current from here I’m going to short out my two connections this won’t damage the panels they are okay to be shorted together in order to get our ISC current short-circuit measurement you do want to be a little careful if you have a very large high-voltage array it can be a little bit dangerous in order to do this connection but for a hundred volt is no problem doing this in opening and closing this connection so I short them together and then I’m gonna use their clamp on meter in order to detect the current so right now we’re getting right around five point five amps or so and that’s great that matches up exactly with what the back of our panel says so that matches up to what the back of our panel says this is a very good sign all the electrical connections are good and our solar panel is putting out the right power so those are two different measurements vo C and ISC but unfortunately they’re both imperfect for testing solar panels because we’re not actually testing it under load we’re testing it under full current and we’re making sure we have full voltage out of here but we are not testing is the panel under full maximum power conditions unfortunately that test is a little bit harder and require specialized equipment so you’re not going to be able to do it out in the field but with these two measurements we can basically troubleshoot most of our panel issues in order to determine if we have a problem so let’s say we did our voltage measurement and we’re getting low voltage or we did our is see our current measurement and we’re getting low current as long as we test it on a nice sunny day we can use those measurements and say we probably need to do some mechanical troubleshooting of our solar panel the first and most common issue we want to check for is a loose connector so the way these mc4 connectors are manufactured is the internal contact is either crimped or soldered to our wire and then insert into the connector and it needs to be fully inserted and locked in place what happens sometimes is the terminal is not fully inserted into our mc4 connector so when they’re plugged together they don’t make full contact sometimes they’ll even make partial contact which makes troubleshooting a little bit more tricky it means we can get our voltage measurement but we might not get full current on a current measurement cuz it’s unable to conduct all the current through there so to make sure our terminals are fully seated inside of MC 4 we’re going to want to remove or loosen up the back gland sometimes these can be on a little tight and you’re gonna need some wrenches in order to get it loose so here we unscrew and loosen up the back waterproofing gland and now we can give it a good pull and tug to see if it’s fully seated in there if you can pull on your MC 4 and it pops out then that means it probably wasn’t fully seated and you want to really push it in tight sometimes you hear a click and you’ll see that it’s nice and fully seated inside our MC 4 connector so we’ll want to do this to both of the terminals plus you’ll want to check any other connections in your system that can include your extension wire so if you’ve checked your MC fours and they’re all fully seated and you’re still not getting the full voltage or your full current there’s another thing you want to check on the back of all the panels is what’s called a junction box you can see here I’ve already removed it so we can see what’s inside so here our wires are coming in to our terminal strip there’s three different connection methods that are used here one is a soldered connection second one is a crimp down connection and a third is a clamping connection with the screw you’re also gonna see our diodes here we can talk about those dials do in another video but what you’re gonna want to check is you’re gonna want to make sure these screws are fully tightened down if you have screws if you have a crimp connection you’re gonna want to
make sure it’s tightly crimped around your wire and then you have a secure connection we can see here both of them are fully seated sometimes if they’re screws these can vibrate and rattle loose shipping or they just weren’t fully tightened in the first place same with the crimps if the crimping tool was slightly worn out they might not be getting great crimps on it and you might have a slightly loose connection in that case you can take your pliers and you can crimp it and fully crimp it down what’s even better is you have a soldering iron you can go in there and reefs are the wire to make sure you have a nice good connection to your panel this is not as common of an issue as loose MC4s but it still does happen from time to time and the good part is if you can find this and fix it it’ll save you from having a ship your panel back and getting a replacement those are the most common issues we see with solar panels that either have low output or no output the solar panels are very simple just consists of the solar cells connected on series and our wires bringing the power out under very rare circumstances you can go look very closely at your panel and see if something happened with say the soldering of the busbars and interconnects from cell to cell very rarely they’ll be a manufacturing defects with shorted out this edge of the cell or shorted out other parts of the panel which are causing no power output unfortunately there’s no fix for those and you’re gonna have to swap out your solar panels but otherwise with these few simple steps you’re gonna be able to diagnose and troubleshoot any solar panel or low power output issue so that’s troubleshooting your panels this is Mike with RPS solar pumps all we do here at RPS solar pumps is solar water pumping if you need to pump water whether it’s from a well an above ground source or anywhere else give us a call we can get you set up with a system today.