Series Solar Panel Connections
When we connect the solar panels in series the output voltage is increased . To apply the series connection method, it is a better practice that all the solar panels should have equal power ratings and be the same type.
For wiring, the solar panels in-series connection goes as follows:
- The positive terminal of the first panel is connected to the negative terminal of the second panel
- The positive terminal of the second panel is connected to the negative terminal of the third panel and so on.
In the end, we have the positive terminal of the last panel connected to the negative terminal of the first panel .
For example, we have four solar panels each has 72 Watts output:
- Panel #1: 12 V and 6 Amps, 72 Watts
- Panel #2: 12 V and 6 Amps, 72 Watts
- Panel #3: 12 V and 6 Amps, 72 Watts
- Panel #4: 12 V and 6 Amps, 72 Watts
This is the maximum output of the panel when the sun fully shines.
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How To Connect Two Solar Panels To One Battery
Connecting two solar panels to one battery with one charge controller is easy. This article will explain how you do it, including schematics.
First of all, you should know this:
You will damage the battery when you connect your solar panels directly to your battery . You need a device that measures the state of charge of your battery and charges it accordingly, just like a car battery charger.
The device we are going to use is called a charge controller. Like the word says, it will control the charging of your battery.
Purpose of a charge controller:
- Stop the charging when the battery is full
- Adjust the charging voltage and current
How Do Solar Panels Wired In Series Compare To Solar Panels Wired In Parallel
A charge controller is a determining factor when it comes to solar panel wiring. Maximum Power Point Tracking charge controllers are for wiring solar panels in a series, where Pulse Width Modulation charge controllers are used to wire solar panels in parallel.
To understand how wiring in series works in comparison to how parallel wiring works, lets think for a moment about how Christmas lights used to work.
If a bulb burned out, came loose from its socket or broke, the entire string wouldnt light up. This was because the lights were wired in a series. You would have to locate the problem bulb and replace it or reseat it to get the string of lights to work again.
Today, most Christmas lights feature a form of parallel wiring that allows for strings of lights to stay lit even when there is one troublemaker in the string.
Circuits wired in series work the same way for solar panels. If there is a problem with the connection of one panel in a series, the entire circuit fails. Meanwhile, one defective panel or loose wire in a parallel circuit will not impact the production of the rest of the solar panels.
In practice, how solar panels are wired today depends on the type of inverter that is being used.
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Series / Parallel Wiring
Watts – Since we connected four groups of four panels together in series and parallel, this solar system will output 1008w of power per hour maximum . This is a great amount of power.
Battery – With four groups of four panels and batteries wired in series and parallel, your battery capacity is at 420 amp hours – so your battery can store/spend 420 amps total in the period of one hour. This is a great storage capacity.
Amps – With four groups of four panels/batteries wired in series and in parallel, your amps are at 14 amps which means you’ll be able to charge your battery bank faster and take better advantage of available daylight hours.
Volts – With four groups of four panels/batteries wired in series and in parallel, your panels’ volts are at 72 volts and your battery bank’s volts are at 48 volts which means you’ll be able to power up to 48 volt appliances.
This 16-panel series / parallel arrangement adds some balance to your solar system by bringing the volts and amps up to an acceptable level while providing enough power, charge speed, and storage capacity to handle most energy needs. You can now begin to enjoy some real energy independence.
But what if you want to power 120 volt appliances? Then you’ll need to add some stress to your 16 panel/battery solar system by wiring it only in series.
Solar Panel Wiring Usage And Limitations
Watts – The reason why this arrangement is limited is that with only one panel, you can only produce up to 63 watts per hour maximum .
Battery – With only one battery, you can only store one battery worth of power. Since your battery can store 105 amp hours worth of energy, you’ll have to spread those amp hours out according to the amp rating of your appliance for as long as you can. If you stick to small appliances with small power loads you should be able to get some minimal energy savings with this system in optimal sunlight.
That might seem great but if you started adding more appliances and power loads, you would likely run out quickly. Also for the health and life span of your battery, you should try to never discharge your batteries more than 30% empty. As a result, this limits your available power even more.
Amps – Furthermore, your system would only have 3.5 amps so you would be producing power or charging your battery kind of slow.
Volts – And with only 18 volts and 12 volts , you would only be able to charge appliances with a lower voltage rating, like 12 volt but not 24 volt or higher.
But don’t get too discouraged, this solar arrangement is still useful and practical, as long as you don’t expect too much out of it.
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How Many And What Sized Solar Panels Are Required To Charge 2 Batteries
To charge two batteries, you may technically utilize any size solar panel. However, the smaller it is, the longer it takes to charge.
With an average of 5 hours of sun and 450 watts per day, it will take a 100-watt solar panel 6 days to charge two 200ah batteries.
However, with three 100-watt solar panels, you may generate up to 1500 watts each day.
A 300-watt solar array can charge the batteries in two days, even if the daily output is just 1200 watts.
This is predicated on the premise that the batteries are completely depleted. The depth discharge rate of most deep cycle batteries is 50%. It will take less time to recharge the batteries if you do not entirely deplete them.
In the end, one solar panel can charge two batteries, but more panels or a single enormous one will make a significant difference.
If you want your batteries to charge quickly, invest in a large solar panel or many smaller ones that are connected together.
Keep in mind that solar panels and batteries are only two parts of the puzzle. A charge controller is also required to prevent the batteries from being overcharged.
Why Do I Need An Electrical Wiring Diagram
A wiring diagram is a visual representation of the system. It will show you where each wire connects to and from, such as what goes into your inverter and then comes out of your solar panel. A wiring diagram will also show you where to wire the DC disconnect . This is a very important part of your solar system. If something happens with one of your solar modules, it is very important that you can disconnect the power from your batteries and prevent a fire.
If you would like to know if we can install solar and put thousands of dollars in your pocket for doing it, use the form below to submit your electric bill for a no cost, no obligation evaluation.
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Batteries Made Of Lead
In the field of solar batteries, lead-acid batteries are tried and reliable technology. For a long time, these deep-cycle batteries have been used to store energy since the 1800s, in fact. And its because of their dependability that theyve been able to stay in business.
Floating lead-acid batteries and sealed lead-acid batteries are the two primary kinds of lead-acid batteries.
Solar Panels In Series
In a series connection, the NEGATIVE output cable of the first panel is connected to the POSITIVE output cable of the second panel. Then the NEGATIVE output cable of the second panel is connected to the POSITIVE cable of the third panel. And so on, for however many solar panels you have.
Finally, the POSITIVE cable of the first panel and the NEGATIVE cable of the last panel are connected to the solar charge controller.
* Solar fuses are technically required in this wiring example, but are excluded here for simplicity.
In a parallel connection, the POSITIVE output cables from all the solar panels get joined together using a branch connector. The same is done for all the NEGATIVE output cables.
The branch connectors take all the positive and negative cables and output a single POSITIVE and NEGATIVE line, which then gets connected to the solar charge controller.
For simplicity sake, the above diagram does not include solar fuses. We talk more about that below.
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Wiring Solar Panels In Parallel
When wiring solar panels in parallel, you will want to make sure that the current levels of each panel match. If one panel has a higher current than the others, it could damage the other panels.
To connect solar panels in parallel, connect the positive terminals of all the panels together and do the same with the negative terminals. Make sure that there is no electrical current running through them.
Identify The Positive And Negative Cables On The Solar Panels
There are two ways to identify the positive and negative cables on your solar panels.
The easiest way is to look at the cables themselves and see if theyre already marked. For instance, my solar panels both had plus and minus tags attached to the positive and negative cables.
If yours dont, there may also be small plus and minus signs on the MC4 connectors or the junction box.
If your panels give no indication which cables are which, use a multimeter to measure each panels open circuit voltage . If the voltage is positive, the positive multimeter probe is touching the positive cable. If the voltage is negative, the positive probe is touching the negative cable.
Tip: If youre worried about forgetting which cables are which, mark the positive cable on each panel with some tape.
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Connect The Cables To The Y Branch Connectors
These are Y branch connectors:
Theyre used for wiring 2 solar panels in parallel. Youll need to get a pair to complete these steps.
Connect the 2 positive solar panel cables to the compatible Y connector. This will likely be the FFM connector.
Then connect the 2 negative solar panel cables to the other Y connector. This will likely be the MMF connector.
Note: If using MC4 inline fuses, connect them between the each positive cable and the Y connector.
Done! The 2 solar panels are now wired in parallel.
Need to wire more than 2 solar panels in parallel? Simple just get the right size branch connector.
For example, if wiring 3 solar panels in parallel, use a pair of 3 to 1 branch connectors.
And if wiring 4 solar panels in parallel, use 4 to 1 branch connectors.
Note: When wiring solar panels in series, I showed you how to confirm that they were correctly wired by checking the open circuit voltage of the 2-panel string with a multimeter. Technically, you could check that your panels are properly connected in parallel by measuring the strings short circuit current . BUT, many multimeters have a 10 amp current limit, and, in many cases, two solar panels wired in parallel have a combined short circuit current that is greater than 10 amps.
Connecting Solar Panels Together In Parallel
The next method we will look at of connecting solar panels together is whats known as Parallel Wiring. Connecting solar panels together in parallel is used to boost the total system current and is the reverse of the series connection. For parallel connected solar panels you connect all the positive terminals together and all of the negative terminals together until you are left with a single positive and negative connection to attach to your regulator and batteries.
When you connect solar panels together in parallel, the total voltage output remains the same as it would for a single panel, but the output current becomes the sum of the output of each panel as shown.
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How Do Solar Panels Connected To The Mains
Solar panels can be connected to the mains in two ways: through a grid-tie inverter or a battery bank. With a grid tie inverter, the solar modules are connected directly to the electrical grid and used to send power back and forth as needed. With a battery bank, the solar panels charge batteries that then provide power to the homes electrical system.
Series Connection Of Solar Panels And Batteries With Automatic Ups System 24v Installation
In this solar panel wiring installation tutorial, we will show how to wire two solar panels and batteries in series with automatic UPS/Inverter for 120V-230V AC load, battery charging and direct DC load from the charge controller.
PV panels and batteries are available in the range of 12-23-36V etc. The most common is the 12V system. Obviously, the series connection is less common for solar panel and batteries installation as the system will only increase the level of voltage which is only applicable in a 24V inverter system. In other words, additional load cant be fed up by this system as well as the battery charging process will be slow as compared to the parallel connection. This is due to the same amperage capacity in series connection for both batteries and PV panels.
Most solar panels and batteries come in 2/24/36V etc. If you want to add extra capacity to the system, you will have to wire the system in parallel configuration. Suppose a single battery powers up a ceiling fan for 6 hours. The same fan can be powered up for 12 hours by two batteries connected in parallel. In addition, The two parallel connected solar panels will charge the batteries quickly and power up extra load.
V1 + V2 + V3+ Vn
i.e.
12V + 12V = 24V.
While the Ampere hour of battery as well as current in solar panels remains same
I1 = I2 = I3In
5A = 5A = 5A
100Ah = 100Ah = 100Ah
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Connect The Positive Cable Of The First Solar Panel To The Negative Cable Of The Second
This step takes all of 10 seconds. Heres a video showing you how to do it:
Thats it!
Your two solar panels are now wired in series.
If you want, you can confirm theyre correctly wired in series by taking the panels outside and using a multimeter to measure the strings open circuit voltage. It should be close to the sum of the 2 panels open circuit voltages.
For instance, each of my panels has an open circuit voltage of 22.6 V. The sum of these is 45.2 V . So I expect the open circuit voltage of the 2-panel string to be close to this.
Indeed, when I took it outside and measured its open circuit voltage, I got a reading of 38.7 V . Thats in the ballpark of 45.2 V, so I know my 2 panels are properly connected in series.
Want to wire 3 or more solar panels in series?
Easy. Just connect the positive cable of the third solar panel to the negative cable of your 2-panel string. You can string together as many panels as you want like this.
Voltage And Amps In Parallel
To wire solar panels in parallel, connect all of the positive terminals on each panel together and then do the same for the negative terminals. The resulting current will be the sum of all of the panel amperages in the parallel array. However, the total voltage will be equal to the output voltage of a single panel.
For example, in the graphic above, we have three 18-volt, 6-amp panels wired in parallel. The output current is 18 amps , yet the output voltage is still 18 volts.
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Wiring Solar Panels & Batteries In Series
There are two ways in which you can wire solar panels and batteries- series or parallel. In a series connection, the voltage of all the batteries is added together, while in a parallel connection, the current of all the batteries is added together. When wiring solar panels and batteries in a series-parallel connection, it is important to remember that if one battery dies, the whole system will go down.
In order to wire solar panels and batteries in a series-parallel connection, you will need the following:
- Battery charge controller
You can also wire solar panels and batteries in a series-parallel connection, which is useful if you want to increase your battery capacity without adding more batteries.
In this type of wiring, you wire the panels in parallel and then connect them to a single battery or power source in series. This type of connection allows you to use fewer batteries than you would if the panels were wired in parallel.
