Planning to get a solar panel system and the installer asks parallel or series. Now that is confusing, and what does this even have to do with a simple solar panel connection? Yeah, this happens, and you are not alone to think this way. However, it is not as complex as it seems and understanding connecting solar panels in series vs parallel is quite easy. All you need to do is to remember the connection pattern and its effect. And if you wonder do solar panels charge faster in series or parallel, then find out with us.
What is a Circuit?
Before you move ahead with a series and parallel connection, it is better to understand the basics of the circuit. A simple path followed by electrons to flow through is an electronic circuit. A battery, wire, and bulb circuit are one of the simplest. Electrons moving through a circuit create voltage and the difference in the charge between two points is measured in volts and current. The rate of charge flowing through the circuit is measured in amps. The electrical properties of electrical components in a circuit affect the flow of current.
How Connecting Solar Panels in Series Vs Parallel Differs?
Solar panels are made from silicon-made monocrystalline or polycrystalline solar cells. Solar panels differ in size, voltage, and output. Thus, the main difference faced in series or parallel arrangement is voltage and output.
1. Series Solar Panel Wiring
a) Voltage and Amps
For wiring solar panels in series, the positive terminal on one panel is connected to the negative terminal on the second one. The same pattern continues throughout the whole series. The overall voltage of the panel will be the sum of the voltages of all interconnected panels. The total current will be the output current of one panel.
For example, 3 panels with 18 volts and 6 amps are wired in series. The output voltage will be 54, which is the sum of 3 panels (18+18+18), but the output current will be 6 for the entire series.
b) Best Applicable
Solar panels wired in series are best for unshaded. Since panels are connected in a series, their overall voltage is dependent on each other. If a panel or a part of a panel is shaded, it will bring down the power output of the entire system.
Series connection is best if you need a low ampere system and to calculate this multiply current by voltage. Higher voltage means lower ampere and this series will work well with less expensive wires. Also, it is easier to use.
For a series of solar panels, you need a Maximum Power Point Tracking (MPPT) charge controller to regulate the voltage and current traveling from solar panels to the battery bank. With a Maximum Power Point Tracking charge controller, there will not be any power loss while maintaining the voltage.
Also Read: Can You Connect Inverters in Series?
2. Parallel Solar Panel Wiring
a) Voltage and Amps
All positive terminals on each panel are interconnected and the same is done for negative terminals. It means positive is connected with positive and negative with negative. The sum of amperes of all panels is the resulting current in such wiring. The total voltage of a single panel is the total voltage for the entire series.
For example, 3 solar panels of 18 volts and 6 amps each wired parallel will have 18 amps total output current (6+6+6) with 18 volts as its output voltage. There is a major difference between connecting solar panels in series vs parallel.
b) Best Applicable
Parallel-wired solar panels work independently; thus, they are best for mixed light condition requirements. Partly shaded solar panels or panels will not affect the overall output of the series.
Also, this wiring is ideal when a low-voltage system with Pulse Width Modulation (PWM) charge controller is preferred.
Output charging current is increased if the nominal battery charging voltage matches with panel output voltage.
What are Solar Panel Series Vs Parallel Pros and Cons?
To understand the solar panel series vs parallel pros and cons, let’s first start by understanding the pros of series and parallel.
Pros of Series
- Lesser cables are required.
- Does not necessarily require thick cables.
- With the temperature of solar panels exceeding 25° Celsius, there is a drop in voltage. This drop increases with an increase in temperature but with multiple solar panels in series, a drop in voltage can be managed.
Pros of Parallel
- Does not deal with high voltages hence it is safe to handle.
- Either a Maximum Power Point Tracking (MPPT) or Pulse Width Modulation (PWM) solar controller can be used. A good pulse width modulation solar controller at an affordable price will also be sufficient.
- Mixed solar panels can be used
- The system does not need special cooling as the pulse width modulation solar controller does not produce excessive heat.
Now let’s learn about the cons of the solar panel series vs parallel.
Cons of Series
- The bypass diode and blocking diode are required for each panel to maintain a balance between panels.
- Due to heat generated by the MPPT controller, the voltage needs to be altered to suit the voltage of the RV.
- Needs expensive MPPT installation because a cheaper MPPT and a pulse width modulation (PWM) solar controller would not work.
- Series solar panels carry higher voltages; thus, it is dangerous.
- Without the same Voltage Maximum Power (VMP) and Open-circuit Voltage (Voc) ratings solar power harvesting will be the lowest Voltage Maximum Power (VMP) and Open-circuit Voltage (Voc) for all available panels in the series.
Cons of Parallel
- Multiple solar panels may not supply combined voltage to charge the battery because the connection combines amps.
- Thick cables in large quantities are needed. In connecting solar panels in series vs parallel you need to consider the pros and cons of both.
Do Solar Panels Charge Faster in Series or Parallel?
Wiring parallel or in series depends on whether you want to increase current or voltage. Current is additive in a series wiring whereas voltage is additive in parallel wiring of the solar system. Therefore, solar panels wired in series will charge batteries faster in comparison to the ones wired parallel.
Also See: Multi Busbar Technology in Solar Panels
Does Solar Wattage Increase in Parallel or Series?
Wattage is the amount of power consumed by a device and is measured in watts. To determine wattage, you can multiply current by voltage. For example, you have 2 devices, and each has the same voltage but different currents. Thus, devices with a higher current will consume more wattage.
Theoretically, it should increase in parallel wiring because if you connect two devices with the same voltage and different currents, more watts will be consumed.
Do I Need Diodes for Solar Panels in Parallel?
A diode is a 2-terminal electronic component that primarily conducts current in one direction. Also, its resistance is low in one direction and high in another. In a parallel connection, blocking diodes should be used in each parallel-connected branch. A bypass diode is required due to the following reasons:
- One panel does not drive a current in the forward direction to another panel.
- When one panel is shaded, the open-circuit voltage of unshaded panels exceeds the open-circuit voltage of shaded panels. In such situations, a fraction of the current runs back into the dimmer panel.
- If panels are run-closed circuits and near to maximum power point, for both panels in connection, the operating voltage is lower than the open circuit voltage, thus forward-moving current needs to be suppressed.
Therefore, blocking diodes is generally recommended so that batteries do not discharge over panels. Although the charge controller handles such situations efficiently, to avoid imbalance between panels, the diode should be installed.
Also Read: A Guide to Solar Panel Dimensions
Do I Need Diodes for Solar Panels in Series?
Understand diodes as they are important in connecting solar panels in series vs parallel. Diodes are required for maintaining voltage balance between panels. For a series of solar panels, a bypass diode is preferred. This faulty panel is bypassed, and an alternative path is provided for the current to flow. With this continuity of power, production is maintained.
What is Mixed Panel Size in Series Vs Parallel?
Technically, using mixed solar panel sizes is possible in either type of connection. But there are ups and downs in each connection regarding mixed panels. Take a look.
1. Series Solar Panel Connection
Using mixed panel sizes in series connection means loss of output produced by big panels as it is greater than the output of smaller panels. At times when big panels push through the bypass diode there will be no contribution from smaller panels.
2. Parallel Solar Panel Connection
However, using mixed-wattage panels in a parallel connection results in full solar energy harvest according to the capacity of each panel. This is possible with a pulse width modulation solar controller.
Also Read: How Many Volts Does a Solar Panel Produce?
What is the Best Way to Connect Two Solar Panels?
Once you understand the difference between parallel and series solar panel wiring, you can determine which is best for you. It all depends on the application and voltage you require for powering the house and appliances.
However, parallel wiring is considered better for several electrical appliances as it allows the continuous operation of panels. Functioning is not hindered even when one or a part of any solar panel is shaded or not working properly.
But sometimes to run your inverter certain voltage requirements need to be met. In such a situation, a critical balance of ampere and voltage should be achieved to ensure solar panels perform to their best capability. Therefore, a solar installer will guide you and install a hybrid wired system for balanced output.
Well, connecting solar panels in series vs parallel depends on the application, location, and type of power you need. However, this is an important decision when installing the solar panel system. Do solar panels charge faster in series or parallel? The answer to this is parallel because this type of connection is not hindered by any malfunctioning panel and its current is added from all panels.
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