The terms Series and Parallel are quite common in the solar and battery backup industry. However, we often find that our clients are not always perfectly clear on what these terms mean or how they affect their configuration. Today we will be going over the definitions, differences, and relevance to power storage and production, when discussing Series and Parallel circuits.
Both solar panels and batteries are commonly configured in Parallel. The basic rules of this type of connection are as follows:
1. The Circuit has two or more paths for current to flow through.
2. The Voltage remains the same across each component in the circuit.
3. If one of the paths is broken, current will continue to flow in all other paths.
4. The sum of the currents through each path is equal to the total current of the originating source.
This type of configuration is most common in small, off-grid systems. When connecting in parallel, the amps of the various sources will increase, while the voltage remains the same. For example, (1) 12V - 50 Ah Battery tied in parallel to another (1) 12V - 50 Amp battery, will result in a 12V 100 Ah Storage Bank.
When connecting solar panels in parallel, the high amperage production can prove to be an issue when working with many panels. Therefore, parallel connections are more common amongst smaller, off-grid systems. Transferring many amps across a vast distance can prove difficult, and may require a thicker gauge cable, to ensure loss of power in transit is minimal.
Series connections are quite common as well and are typically utilized amongst larger off-grid panel arrays, when traveling further distances and with MPPT Charge controllers. Lets go over the basic rules of series connections:
1. The same current flows through each part of a series circuit.
2. Voltage applied to a series circuit is equal to the sum of the individual voltage drops.
3. If the circuit is broken at any connection, no current will flow.
The main benefit of a series connection is long distance connections. By connecting in series, the voltage will increase, while the amperage remains the same. This allows for optimal placement of panels in relation to southern solar exposure.
The main drawback to series when discussing solar panels, is shade or coverage issues. When one panel, even in a string of 10 panels is shaded, it will affect the entire arrays power production.
Often times for compatibility purposes, a solar array will be set up in a Series-Parallel configuration. This will allow for proper connection with the input requirements of the systems charge controller. The most common factor here is typically input voltage.
When performing a series-parallel connection, you are simply paralleling 2 or more equal strings together. This is demonstrated in the diagram below. There is no particular benefit to this type of configuration, it is simply performed to match input requirements of the charge controller/inverter being used.
If you have any questions on Series, Parallel or Series-Parallel connections, please leave us a comment! We hope you found this topic informative. As always, we are just a phone call away (877-548-3387) and are happy to offer our expertise on all of your Solar needs!