Connecting Multiple Solar Panels

There are 3 ways to connect solar panels; parallel, series, and a combination of parallel and series. The first way I am going to talk about is parallel because this is probably the most common way that panels will be connected. For this example I am showing you connecting panels that are for a 12 volt system.  This is how the panels that I have built in my other instructables are connected, and feed my solar charge controller.

In this first image there are 3 solar panels.  If you look at the arrows along the white and red lines they are showing the direction of flow. The white line is the negative connection, all 3 panel negative wires are just simply tied together and to the wire that runs back to the negative connection on the charge controller.

The red line is the positive connection to the panels.  You will see a symbol that looks like a triangle pointing down at a horizontal line.  That symbol is for a diode, also known as a blocking diode.  What this diode is doing is only allowing the positive electrons to flow in only one direction. When looking at this symbol the triangle points in the direction of flow, when looking at the diode in your hand there should be a colored line around one end of it.  This line represents the line in the symbol that the triangle is pointing to.  The non-colored end would be the “in” side, and the end with the colored line around it would be the “out” side. By installing these diodes on each panel it stops the electrons from going back into other panels. Diodes also use up a small amount of voltage, so don't go crazy and put to many in or you will to low to use.

If you look below the panel to the left you can follow the red arrows from the panel down and make a right turn to the diode. Then they continue through the diode and down the line to the end where they would be connected to a solar charge controller.

Step 1:

In this next step you can see that the left panel is covered, let’s say that a tree was blocking the sun from this panel.  If you look below this panel at the red line you will see that there are no arrows coming from the panel to the right hand bend. And if you look to the right of the diode symbol you can see that the arrows have changed direction from the previous step.  This is how the diode works.  The diode is stopping the electrons from pushing their way back to the panel that is not producing power.  If this diode was not in place then the panel not producing could be damaged.  Also you would be losing some efficiency from the other panels because they would be letting power flow through the nonproducing panel as the electrons are trying to reach the negative side of the panel.
Hi <br>I am setting up a solar array and would like a little information if you peeps could help here is the equipment i have at the moment <br>15 x 315w lg neon2.<br>1 x outback flex 80.<br>1 x victro 5kw 48v.<br>Now i was thinking of putting it like this<br>5x3 in series thus getting around 99v but only 9 odd amp per three panels.<br>My question is .<br>I will be using normal 4mm cable with mc4 connectors for each array of 3.will i have to step up the cable size when they are joined together say 6mm or even 10mm as the total amp at max is around 45amp is it not <br>? Or am i missing something here.TIA
<p>hi there</p><p>I have a 6000W 48V inverter with 60A (MPPT)charge controller. I have 16 275W (21V) mono solar panels. What is the best way to connect these panels in an array to get maximum efficiency. (how many in series , how many in parallel?) I tried 4 series, and 4 parallel, but the amps from the charger is very low (aprox 14amp)</p><p>kind regards</p><p>Christo</p>
<p>You have the best configuration.</p><p>With your configuration, 4 x 4 you should be seeing 84V @ 52 Amps or 4,360 Watts DC. Most likely there is a problem.</p><p>Disclaimer</p><p>Warning before doing the following testing wear rubber gloves suited to protect from getting a electrical shark. Any voltage over 40v will give you a shark. Always connect the panels LAST, after connecting everything else.</p><p>This is not for the faint hearted. Since most solar arrays are install on the roof or high places, you should be wearing a secured harness, to protect from falling. It maybe best to get professional help.. I take NO responsibility for any harm caused in preforming the following trouble shooting. Again I stress get help from a professional. To proceed, the risk is your's and your's alone. </p><p>The best way to test any part of a high current solar panel array is to use a resistive load. There are good resistive loads that can be purchased, and used with an ampere meter, for more accurate indications. </p><p>A cheap resistive load test can be constructed using 4 x 250 w @120vac incandescent light bulbs (don't use fluorescent) wired in PARALLEL forming a 1000 watt load. Connect this load to one of the 4 panels set in series. 84v @ 13 amp supplies about 1,093 watts, with strong sun. Might use 3 X 250, if the sun isn&rsquo;t that strong where the panel output is reduced.</p><p>Only apply this load to sections that are broken down to 800 to 1,200 watts. As in this case each section of 4 panels in series, supply about 1,100 watts. Each section must be completely disconnected from the rest of the array. For tests over 1000 watts, only connect for a very short period, less then 1 second, as bulbs may be damaged.</p><p>Follow through the system, checking next the output of the charge controller and the output of the inverter. At the inverter output the supply is regulated to 120 vac, bulb damage isn&rsquo;t a concern. </p><p>As you, descend from the panels to the charger to the final output side of the inverter, there will be slight dimming due to losses in each. </p>
<p>can you tell me please about</p><p> controlled diod so i will purchase</p>
<p>i have a bunch of 3-6 v solar panels ( yard accent lights that have been thrown out due to batteries being dead.) im trying to figure out the best way to chain them all together and make a 12v array it is understood that i might have to use a couple different methods to do this. the first step im looking for is to make the panels all equal 12v that would be a parallel connection if im understanding this correctly then i would need toput them into a series to pump up the amperage? also im currious if i were to use one of the charge controling chips from said light would that work?</p>
<p> I would not recommend making an array with cells that have different ratings. The current output of a series connection will be limited by the cell with the lowest current rating. You would need to include suitable bypass diodes between each cell to prevent overheating (and possible damage) and even then your panel will not be very efficient working in that way. </p><p>Answering your question: NO. To increase the output current you'd add cells in parallel (voltage remains the same or an average of all cell's voltages if they are different) , to increase the voltage you'd add cells in series ( the current again, would be limited by the cell with the lowest current rating). I'm attaching an example . </p>
<p>Assuming that each panel was rated at 5V and 0.5 amps</p>
What if I have 24v system how am I to connect
Dear sir Is it possible to connect more than different voltage solar panel and the ability, for example, 30-volt 250-watt and 250-watt 37 Volt
<p>Sir i have two solar panels 150W with same amp and voltage as you can see in the below picture. And I have a UPS, Sir i wnat to coonect these two plates with ups so which method should I chose SERIES OR PARALLEL</p>
<p>Glad to see that the person directing ALL THESE PEOPLE to connect their solar panels together knows all about the 'POSITIVE ELECTRONS'. Them pesky positive electrons, always trying to travel a direction they ain't supposed 'ta!</p><p>And darn those diodes, because they 'use up a small amount of voltage', because, you know, that's totally a thing that can be used up. Learn some basic electrical engineering before you write an article that will be used by countless people in potentially dangerous situations.</p>
<p>Agreed. The theory from what I read seems right, but as soon as I got to 'positive electrons' it's obvious anyone who has not actually studied this just became confused, or got the wrong idea of the way the system works and could very well cross-connect something later and cause damage or wounds. <br>Teach correctly or stay out of the way, we're dealing with something that literally kills thousands every year, and this is far from the first link I've clicked on while looking for references. </p>
<p>if you want to charge 2(double Battery )then see series and if single then see parallel circuit</p>
<p>Hello <br>I need to known how many combination are possible for solar plates.I have 3 solar plates of 150 Watts,12 volts and 8 amperes,Which combination is best for using with a ups battery of 180 amps? I have liquid battery. I am from Pakistan. My email id is bilalengineer313@gmail.com</p>
<p>Do i need the blocking diodes if im using a charge controller?</p>
<p>dear sir,please tell me some advantage and disadvantage of connecting two dc- dc converter (boost circuit) in series? what is its effect if we connect two boost converters in series and feed there output to delta inverter ( 5kw)??</p>
Dear sir, i have gone through, the article its very useful, can you explain the consequences if we use different wattage panels, what kind of connections we would prefer. I have three 20 watts panels and four 10 watts panels
<p>What type of circuit would you need to build in order to be able to switch the panels from series to parallel? I'm going to have 2 100 watt 12 volt panels. I'm planning to add an AC inverter to supply power to the house which requires them to be in a series for 24 volts. But, I already use one panel with a 12 volt back up battery system that I want to keep as-is, which means I'll need to be able to switch them to parallel to provide 12 volts to the charge controller/batteries.</p>
<p>if you are going to add an inverter why not just add a 12v inverter? i hope you are not planning on running your entire home on 200 watts because you will not be able to do much with only 200 watts. is this a grid tied inverter? i have a grid tie inverter in my solar setup. i have a controller that when my battery bank is full it switches my incoming solar power to my grid tie inverter so it helps reduce my electric bill, but only by a few dollars a year because i only have a small amount of panels.</p>
<p>Thanks for the reply,</p><p>Let me explain.</p><p>I just wanted to do this because a lot of the decent grid tie inverters take a minimum of 24 volts, where-as, my battery backup (Twin 6 volt golf cart batteries at 180 amp storage) the panels charge is 12 volts. (question about this below).</p><p>And yeah, like you, I just wanted to feed a little AC into the house to offset some of the power used by say a window AC unit. I already have the panels for the backup so I figured why not also offset the cost a little by using the power when my batteries are charged (As a backup this is almost all the time).</p><p>The main problem is - there doesn't seem to be a very reliable grid tie inverter available which suits my needs. Doesn't make much sense to buy an inverter that is going to blow up in two years, replacing it costs more than the 125-150 watts I'm going to pulling off of it here and there. Buying a grid inverter that costs $300 doesn't make sense because it will take 10 years (if it lasts that long) to break even. This system is also too small to go through the exhaustive work of hard installing something that outputs 240 volts to a specialized panel.</p><p>One final weird question about the backup system. Up to now, every blue moon when the system has been running (only 400 watts), I've ran extension cords to various things to run them. * If I disconnect my home from the grid at the panel box during an outage by throwing the main disconnect, could I possibly run the inverter into an electrical outlet and therefore not require extention cords? * Or does turning off the main panel switch also disconnect the outlet circuits? I'm trying to get away from requiring extension cords.</p><p>Obviously, if I could do this the backup would be completely removed before the grid is reconnected by turning the panel back on and I would need to disconnect items like the refrigerator, furnace etc.</p><p>Hope that explains things a bit.</p>
<p>How you can DO IT YOURSELF :</p><p>1. Go to http://inplix.com </p><p>2. Search for your solution </p><p>3. Think a little bit </p><p>4. Prepare your screwdriver :)</p><p>4. Build your own tool</p><p>5. Enjoy Free energy for rest of your life</p>
dear sir, I have lived off grid over 10 years. I have run into a situation that no one, including me ,can seem to figure out. Would you be interested in hearing my solar / wind dilemma
<p>Hi,</p><p>Thanks for the clear explanation.<br>I was wondering, I don't use a lot of diodes and I have some IN4001, IN4002 and IN4003 diodes lying around (I think the only difference is the voltage). Are these sufficient?</p><p>Thanks!</p>
<p>Hi</p><p>I have a 5W PV Solar Power Panel 12V Battery Charger Boat Marine, 5Watt Trickle Charge CAR and 12V KIT Offer ISTA-BREEZE&reg; i-500 Small WIND GENERATOR + Charge Controller.</p><p>Will this be sufficient to run 15 to 20 KwH household per day?</p>
<p>no. you need a lot more generation and storage before you even come close to your power needs. if you are using 20 KwH per day then you need to be producing more than that amount and store it so you have power at night. </p>
<p>my GTI has MPPT function. Is there any lost when some of panel is shaded if I dont have diode in panel</p>
<p>depending on the quality of the MPPT it may have a diode internally. you would have to do some research to know for sure.</p>
<p>So what is the advantage of putting them in parallel?</p>
<p>putting them in parallel lets you keep the voltage the same and increase the amperage. if you have a 12v system, and two 12v panels that produce 1 amp in series you will have 24v at 1 amp. if you put those panels in parallel you would get 12v at 2 amps. amperage is what pushes power into a battery or powers a system of some kind. </p>
<p>Bypass diode serves the similar purpose to blocking diode. It protects the shadowed cell from reverse current </p>
Thanks for the info. Would you spec a certain size diode for a 12v system? I'm sure that would depend on the total amps, correct?
<p>The diode will drop about .6 volts. Multiply this times the maximum current from the panel to get the wattage dissipated by the diode. So if you have 10 amps from the panel, it would be 6 watts for the diode. Then the diode should be rated for the maximum panel output voltage.</p>
Thank you for writing up a very clear and concise summary of connecting together solar panels. <br> <br>I'm sure many will find this helpful.

About This Instructable


104 favorites


Bio: I have been an industrial electrician for almost 10 years. This is why many of my projects are electrical related. I am working on a ... More »
More by kalefranklin: Screens for Sifting or Drying Garden Sink Compost Barrel, 3 stage
Add instructable to: