Quick Solar Panel Troubleshooter - How to Check for Problems on Your Solar Panel
There you are, the sun is shining when you get up, but as you walk outside, your solar panel monitor is showing really low output - whats going on?
There are a few simple things you can run through to troubleshoot your solar system. Let's assume that your array has been operating properly for some time. Also that this power drop has gotten worse in a short time or quite suddenly. Before you start, remember that your array produces electricity so take proper care of your safety, if you're not confident, get a professional to assist. If you have more than one array and they are connected in parallel, the system will push out much more power(amperage) than a series connected system. Please take care and throw the cut out switch or remove the battery terminals before you go poking around, and remember that shorting your battery terminals is extremely dangerous. So - respect electricity!
If your solar array is a commercial "off the shelf" system, it may be best to pick up the phone, they should have all the diagnostic suggestions you need. However, if your array is a DIY Solar Panel project then lets make start. We will also assume that you have checked the obvious, like someone hasn't ripped one of the array output leads out with a ladder or something, there are no bullet holes through your array and no pile of leaves on the panel face in autumn. The fall is beautiful but "deadly" with leaves, especially if you are out in the woods. Do the panel a favour, and clean the protective surface from dust.
Now, this sounds obvious, but disconnect the array from your controllers and simply check that current is flowing at the panels output lead. If it's operating properly and power is good, check your controller system. Normally solar cells and arrays are extremely reliable and stand up to weather extremes and even hail if properly constructed. However, there are a few things to keep an eye out for.
Checking the array with a Selective Shading Test
With the panel disconnected, monitor the output with a voltmeter or test load. Before you start by ripping the panel apart, we can locate a faulty cell or wiring section without with a sneaky trick, shade at least 4 cells. Shading just a few cells should drop the arrays output to less than half. If it does not, then the cells in that area of the panel is not working properly. Have a close look at these wiring junctions and tab connections, also look at the wiring of the nearby in-series cells. Any sign of corrosion may be the source of your power problem. This needs to be quickly corrected before you damage cells by overheating.
Over-Heating Problems
This is especially so in hotter climates and locations. Sometimes, the voltage coming out of the system drops during the hottest part of the day and is due to the cells operating outside their optimum temperature range. A typical 12V PV cell is designed to work at about 17 - 18V at 25C. So, you should still get about 12V when efficiency falls at higher temperatures. If your "drop" is worse, then its very likely there is a weak PV cell or poor connections somewhere in the array. With the cover still sealed, check the array output by cooling the array, either shade it for a while or pour water over the array. Disconnect the panel from the system and check the open voltage on your output lead, once cool, your voltage should return to normal. If it is below 18 volts, look for a faulty cell by shading each in turn while watching power output with a voltmeter or test load.
Faulty Connections & Soldering
Over time, oxidation and corrosion can affect electrical metal connections, especially if any moisture gets into the panel. If you live close to the sea, salt air can soon corrode metal and aluminum. Screws can loosen, metal can warp, and electrical resistance can build up. The warping and twisting of a wooden panel container can break connections or even crack a cell. Replace all corroded or oxidized metal parts and connections, rewire the cell tabs if needed. Look for damaged wiring and replace it.
Damaged Blocking Diode
Most PV arrays use a blocking diode to prevent your array from discharging your batteries at night. If you find that your batteries are drained even when there is good sun and nobody has been "hogging" the power, the chances are you have a faulty diode that is allowing power to drain backwards out of your batteries. Occasionally, a diode can short out. Replace the diode, or if in a remote location, remove the diode from the circuit - BUT, remember to disconnect the array at night until you can get a replacement or you will drain your batteries. If you need a quick diagnostic for this, feel free to visit our Solar DIY Info website for instructions of diode testing. Good luck and may your panel keep converting.
There are a few simple things you can run through to troubleshoot your solar system. Let's assume that your array has been operating properly for some time. Also that this power drop has gotten worse in a short time or quite suddenly. Before you start, remember that your array produces electricity so take proper care of your safety, if you're not confident, get a professional to assist. If you have more than one array and they are connected in parallel, the system will push out much more power(amperage) than a series connected system. Please take care and throw the cut out switch or remove the battery terminals before you go poking around, and remember that shorting your battery terminals is extremely dangerous. So - respect electricity!
If your solar array is a commercial "off the shelf" system, it may be best to pick up the phone, they should have all the diagnostic suggestions you need. However, if your array is a DIY Solar Panel project then lets make start. We will also assume that you have checked the obvious, like someone hasn't ripped one of the array output leads out with a ladder or something, there are no bullet holes through your array and no pile of leaves on the panel face in autumn. The fall is beautiful but "deadly" with leaves, especially if you are out in the woods. Do the panel a favour, and clean the protective surface from dust.
Now, this sounds obvious, but disconnect the array from your controllers and simply check that current is flowing at the panels output lead. If it's operating properly and power is good, check your controller system. Normally solar cells and arrays are extremely reliable and stand up to weather extremes and even hail if properly constructed. However, there are a few things to keep an eye out for.
Checking the array with a Selective Shading Test
With the panel disconnected, monitor the output with a voltmeter or test load. Before you start by ripping the panel apart, we can locate a faulty cell or wiring section without with a sneaky trick, shade at least 4 cells. Shading just a few cells should drop the arrays output to less than half. If it does not, then the cells in that area of the panel is not working properly. Have a close look at these wiring junctions and tab connections, also look at the wiring of the nearby in-series cells. Any sign of corrosion may be the source of your power problem. This needs to be quickly corrected before you damage cells by overheating.
Over-Heating Problems
This is especially so in hotter climates and locations. Sometimes, the voltage coming out of the system drops during the hottest part of the day and is due to the cells operating outside their optimum temperature range. A typical 12V PV cell is designed to work at about 17 - 18V at 25C. So, you should still get about 12V when efficiency falls at higher temperatures. If your "drop" is worse, then its very likely there is a weak PV cell or poor connections somewhere in the array. With the cover still sealed, check the array output by cooling the array, either shade it for a while or pour water over the array. Disconnect the panel from the system and check the open voltage on your output lead, once cool, your voltage should return to normal. If it is below 18 volts, look for a faulty cell by shading each in turn while watching power output with a voltmeter or test load.
Faulty Connections & Soldering
Over time, oxidation and corrosion can affect electrical metal connections, especially if any moisture gets into the panel. If you live close to the sea, salt air can soon corrode metal and aluminum. Screws can loosen, metal can warp, and electrical resistance can build up. The warping and twisting of a wooden panel container can break connections or even crack a cell. Replace all corroded or oxidized metal parts and connections, rewire the cell tabs if needed. Look for damaged wiring and replace it.
Damaged Blocking Diode
Most PV arrays use a blocking diode to prevent your array from discharging your batteries at night. If you find that your batteries are drained even when there is good sun and nobody has been "hogging" the power, the chances are you have a faulty diode that is allowing power to drain backwards out of your batteries. Occasionally, a diode can short out. Replace the diode, or if in a remote location, remove the diode from the circuit - BUT, remember to disconnect the array at night until you can get a replacement or you will drain your batteries. If you need a quick diagnostic for this, feel free to visit our Solar DIY Info website for instructions of diode testing. Good luck and may your panel keep converting.
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