How to Test Solar Panels - For Beginners!

guys welcome back to the channel today we will be testing solar panels we'll be using a general purpose multimeter and we'll also be using a specialized solar panel multimeter the purist should love this let's get started okay so these are the three panels we'll be testing these two are identical in make and model one has been used for about eight months and one has been sitting in the garage never used so we're going to see the difference between a fresh panel never used and a panel that's been used for a while the panel over there is a smaller 60 cell panel and we'll be testing that as well and that's used and it's probably about five or ten years old and I purchased all these panels at San Tan solar check them out they got great prices on new and used panels let's quickly go over the stats of our panels the larger panels are 335 watt 72 cell poly panels by risen technology and I got them for 150 each brand new the third panel is a 250 watt Trina solar Santan solar 60 cell poly panel and I got it used for just 45 dollars and I'm guessing it's between 5 and 10 years old last I checked they actually went up in price by twenty dollars since my purchase I love these little panels let's talk about testing first locate the panel specs sticker on the back of your panel here we can see the sticker for the two different panels I will be testing we can see that this is a 335 watt panel by looking at the rated max power value this is in Watts all these values are important but if you are using a regular multimeter you will only be able to measure two of them accurately the open circuit voltage VOC and short circuit current or amps ISC volts open circuit this is the max voltage the panel can produce when not connected or under load open circuit short circuit current ISC this is the largest current the panel will produce when short-circuited for example if we were to connect the ends of the wires from the panels together I means current SC means Short Circuit the voltage at pmax and current at P Max values are the max volts and amps the panel can produce under load when the panel is in use and in perfect conditions we will see these values when using the solar panel multimeter for best results when testing follow these tips be sure to clean your panel before testing do your testing during High Noon when the sun is at its strongest make sure your panel is at the proper orientation and angle for your latitude zip code and time of year there are many websites where you can input your ZIP code to find this information for your area you can download a protractor app for your phone to find the degrees of angle I have linked to one such website as well as the protractor app in the description below I will be using the Frog bro ey800w solar panel multimeter this meter can measure Watts VMP imp and the VOC of your solar panel and display everything neatly in one place we will cover these terms later the ey800w can measure up to 800 watts of solar input this is useful when measuring more than one panel connected in series or measuring very powerful panels over 400 watts there is also a 400 watt version and I just found out a new 1600 watt version as well but a 60 volts Max kind of not useful a multimeter is a general purpose tool for electrical work the multimeter I will be using is a client tools CL 800 digital clamp meter and cost around 130 dollars there is also the cl390 and cost around 90 dollars you can get a basic probe meter for less than fifty dollars the lambdam T28 is a good example these meters are not specifically designed to measure solar panel output accurately as solar panels should be tested under load for this reason I was not going to include using a multimeter to test panels in this video however I realize most people simply want to know if their panels are working or not and are not interested in the electrical minutia a multimeter can certainly do this when using multimeters the a means amps and the V means volts the solid line means direct current the wave or sign line means alternating current the small m means millivolts you will not use millivolts or milliamps when testing solar panels when using a probe only meter no clamp you will swap the positive red lead to the a port to measure amps on this meter 20 amps Max as well as switch the dial to the a position to read amps solar panels produce DC current for volts swap the positive lead to the volts slash ohms port and switch the dial to the V accordingly when using a clamp meter you will use the clamp to read amps Instead This is safer and generally can read a higher number of amps when purchasing a multimeter be sure that it can read a direct current it will either say DC or simply have the solid line you see here some meters can only read AC amps especially with client meters be sure that the Max rated input amps is higher than the short circuit current value of the panel you are testing be sure that the Max rated input voltage is higher than the open circuit or VOC value of your panel that you are testing a 10 amp meter should be able to handle most panels links for these devices are posted below okay so before we actually put the panels in the Sun and test them I want to show how to actually probe the panels properly some panels will have a plug at the top some smaller wattage panels and with some mc4 connectors and versus these ones which have wires coming off the back and you'll just probe the mt4 connectors on the plug the same as these so this one is the positive and this one is negative positive negative all you have to do inside the connectors there's some little pins in there they're called ferals you just insert your probe into the connector and red goes on positive and the negative goes in negative also as a side note if you're using a probe meter when you put the probes because you'll also put the probes for amps and bolts inside of the connectors you will get a bit of a spark so don't be alarmed It's Perfectly Normal don't test this at the end of the cable which goes into your charge controller because you're gonna have a huge number of amps potentially and that's just not the proper way to do it when you're trying to test a single panel all right so our first test is going to be the Trina solar 250 watt panel it's High Noon here in Vegas and it's perfect testing conditions no clouds the panel has been cleaned and it is exactly at 13 degrees tilt angle so let's just verify that with our Pro tracker app you can see we have 13 12 13 degrees anywhere between 12 and 15 degrees is ideal we're going to use the multimeter first and then we're going to use our solar panel multimeter second we're only going to use the multimeter once there's no need to show it for the rest of the panels I have a 10 foot extension cable so that we can read the screens on the machines over here in the in the sun in the shade because you can't see the screens in the Sun okay so whether using a clamp meter or a probe meter when we test the voltage open circuit VOC it's going to be the same we're going to switch it to volts and you're going to have to select the function because right now it's on AC volts switch it over to DC volts there you go and now we can do our test so we're going to plug in the red to the red and the negative to the negative black to Black and we're getting 31.71 volts now this panel has a VOC of 37.6 so it's pretty close all right so next we're going to test the amps this panel has a short circuit current of 8.85 amps so to test the amps you're going to switch it to amps now for a pro meter you're gonna have to move your red lead to the another port to read amps for a clamp meter and we'll just use the clamp but we would still want to switch it to DC and then hold it down to zero to that zero it out make sure your amps are zeroed out so it doesn't give a false reading all right so all we have to do to create a short circuit is plug the cables into each other and that'll create a short circuit and then put your clamp meter on the cable all right so this panel has a short circuit current of 8.85 but we're getting 9 amps so that's kind of interesting it's a little a little higher than uh could be just our meter not exactly calibrated but yeah I shouldn't really ever exceed that rating so that's interesting but uh there it is there's the amps all right so next we're going to use our solar panel multimeter we're just going to connect the mc4 connectors right to the mc4 connectors very simple so red to red black to Black all right so we're just going to do a manual pull 198 Watts VMP voltage max power is 22.57 current to max power is 8.78 and our VOC is 32. so from a 250 watt solar panel we're getting almost 200 Watts which if you account for the cable length it's probably 200 Watts which is not bad for a 5 to 10 year old panel when using the multimeter we saw an ISC of 9 amps and a VOC reading of 31.71 volts but when tested under load using the solar panel meter we only got 200 Watts if you were to try and calculate watts by multiplying these values together we would get 285 Watts which is completely wrong if we multiply the current at P Max by the voltage at P Max found on the sticker we should get exactly 250 Watts these values are when the panel is under load hence pmax or max power this is why panels need to be tested under load all right next up is our 335 watt panel the panel has been cleaned it's at the perfect tilt angle let's just verify that 12 degrees tilt angle is perfect connect up our meter okay we're going to do a manual pull here we go VLC is 40. look at that 300 watts almost from a third from a 335 watt panel we're getting about 300 watts so this is for my new panel purchase new and used for about eight months VMP 30.74 imp 9.54 on this panel we saw an imp greater than the Imp pmax value on the sticker we can see that the panel has a VOC of 45.9 volts when not under load this is due to the voltage drop when the panel is under load the lower the voltage the higher the amps will be and vice versa when under load okay so I'm racing against that we're down to like one inch all right so this is the new risen panel uh 335 watt panel just like the last one but this is brand new never been used in any capacity it's been sitting in the garage Let's test our angle okay it looks like our angle is at 12 degrees which is perfect let's see what we get okay we're gonna do a manual pull here you'll see 43.329 look at that 322. so if I'm a 335 watt panel never used uh we gained 20 watts so you can see when your panels are fresh ly purchased you're gonna get more power and then after I don't know some several months or so it'll decrease by about 10 or so okay here we are at the test array We have basically three strings in parallel so those top three is one string this bottom three right here is another string and that those three up there make up another string and they're all connected in parallel so we're going to use the meters to test the panels when they're in series parallel configuration all right here we are under the solar panels I don't recommend crawling under live solar panels but uh I do it so you don't have to they're currently not connected to the inverter but they are still alive 2000 watts is too much power for the solar panel multimeter to test so we're going to be testing each string individually each string can produce about 650 Watts at Peak power each set of three come into this Branch connector on its own line and this Branch connector is good for 30 amps you don't want to exceed 30 amps on these Branch connectors each line will produce a Max of about 10 amps so like I stated before you don't want a probe at your main lines there's 30 amps right here and if your meter is only good for 20 amps you'll blow up your meter like I said before the panels have to be under load and right now the panels are not connected to the charge controller so when using the multimeter to test a string of panels you'll have to induce the load by other means such as turning on your inverter or charge controller so I'm going to go inside turn on the inverter and turn on a heavy load so we induce a load onto these panels okay so we're pulling about 1500 watts off the panels right now and get our meter set to amps and we're going to test the amps on each string first string is produced in seven point two that's the top string up there second string is producing nine that's almost maxed I think that's this middle string the one I'm under the back string against the wall is producing 6.8 so since we tested each string individually Let's test the main output where all the panels are combined in parallel and see how many amps we get so here's the combiner the fuse and then right here we should have all the amps together see we're reading about 20 amps 22 amps now if you had a probe meter that has a limit of 20 or 10 amps and you were to probe the ends of this cable going to your mppt charge controller you'd actually destroy your meter but a clamp meter can handle much more amps so I always recommend to use a clamp meter handle more amps and it's much more safer when testing multiple panels in series parallel okay so now I disconnected the panels from the inverter so there is no current flowing through these panels we can verify that zero amps so now we're going to use the solar panel multimeter to test these strings individually and this is where this shines because this is even safer than the clamp meter because you don't have to energize your panels in order to test them this already has a load built into it and it can pull its own load so in order to do this we'll have to disconnect the positive for each string never do this when your panels are under load never it even says right on the panels since these are connected in parallel we don't have to disconnect each string on the negative side we can simply plug our meter into the negative main negative and get our reading that way main negative and then we're going to plug our positive into the end of the string on our first string foreign how many volts I think too many volts right these don't handle that many volts 60 volts oh Okay so full transparency here I just destroyed my meter this meter has a voltage of 60 volts Max and three panels together is about 113 volts so this meter is test be mindful of that if you're going to get one of these let's see what we got here and hopefully you can learn something from my Idiocracy nothing noticeable wait wait wait wait yeah she smells okay so yeah look at that that ship is smoked you can see the burn mark on the PCB right there Yep looks like I'll be giving Amazon some more money well it really sucks that I blew up my solar panel multimeter but I have another one on the way already so this meter will cost you about 130 dollars it's actually the same price as a pretty decent multimeter however it is not a replacement to a multimeter if I had to choose between buying a multimeter and a specialized solar panel multimeter I would definitely choose to buy a regular multimeter it'll get far much more use out of this than you would one of these well I hope you found this video useful and if there's anything you think I left out I think I covered everything pretty much let me know in the comments and thanks for watching [Music]

Channel: Nate's DIY Solar

Views: 47,587

Keywords: solar panel testing, solar panel, off-grid, offgrid, off-grid solar, multimeter, EY800W

Id: q4XwpCmEarU

Length: 19min 56sec (1196 seconds)

Published: Tue Jun 06 2023