How to Wire Solar Panels in Series & Batteries in Parallel? 12/24/48V System

Wiring Batteries in Parallel and PV Panels in Series – 12-24-48V Installation

Generally, the 12V system for both solar panels and batteries are very common in residential PV panel installation systems. In more complex and heavy load systems, 24, 36, 48, 72VDC (and so on) are used based on the specific system requirements.

For a 24V DC solar panel system, both the batteries and solar panels may be wired in parallel connection. The same 24VDC system can be achieved by wiring solar panels in parallel and batteries in series in case of the double voltage rated solar panels as compared to the batteries voltage (e.g 24V Panels in Parallel and 12V batteries in Series).

The simple 12VDC system can be achieved by wiring a single 12V solar panel to the 12V battery through a charge controller. In case of multiple units, both batteries and PV panels should be connected in parallel for 12V DC systems.

But the following wiring configuration is a little bit weird and complex as normally. you won’t be able to see these kinds of PV panels configuration but they exist depending on the system needs. We are talking about parallel connected solar panels and series connected batteries.

This wiring can be done for multiple voltages systems when the solar panel voltage rating is half as compared to the batteries (e.g. 6V PV panels and 12V batteries or 12V solar panels and 24V batteries.) As we know that connecting a 12V solar panel directly to the 24V batteries bank is not a smart idea. Now let’s see how we can manage this trouble while bringing the both PV panels and batteries voltage rating in the same level by connecting the solar panels in series and batteries in parallel.

• Related Post: How to Wire Solar Panels in Parallel & Batteries in Series? 24V System

Solar Panels in Series

The two series connected (negative terminal to positive and vice versa) solar panels each have 12V (or 6V or 24V etc), 10A and 120W.  We know that voltage is additive while current is the same in each branch. Note that the voltage is different while current is the same in series connection. This way

Current in Series Connected Solar Panels

I₁ = I₂ = I₃ …… I_n

i.e.

10Amp = 10Amp = 10Amp

Voltage in Series Connected Solar Panels

V₁ + V₂ + V₃ …… + V_n

i.e.

12V + 12V = 24V

• Related Post: How to Wire Solar Panel & Batteries in Series for 24V System

Batteries in Parallel

The batteries have inversely connected as compared to the solar panel connection i.e. batteries are connected in parallel (positive (+ve) terminal to positive (+ve) and negative (-) to negative (-) terminal). Suppose the batteries rating are 24V (or 12V or 48V), 100Ah. In this case,

Current in Parallel Connected Batteries

I₁ + I₂ + I₃ …… + I_n

i.e.

100Ah + 100Ah = 200Ah

Voltage in Parallel Connected Batteries

V₁ = V₂ = V₃ …… = V_n

i.e.

24V = 24V = 24V

Cautions:

• Only the same rated solar panel can be wired up either in series or parallel connection. In other words, 6V pv panel should not be connected with 12 or 24V PV Panel.
• Similarly, only same rated batteries should be connected in series or parallel configuration. This means a 6V battery should not be connected with 12V batteries.

Good to Know:

The series connection of batteries won’t add up the Ah capacity i.e. it will only add up the level of voltage as the current remains the same in series connection. If you want to increase the Ah (Ampere hour) capacity of batteries, you may connect them in parallel where the voltage remains same and Ah capacity of cells increases. Same is the case for series and parallel connected solar panels.

• Related Post: How to Wire Solar Panel & Batteries in Parallel for 12V System

The following wiring diagram shows that two 12V (*6 or 24V), 10A, 120W solar panels are connected in series which are further connected to the two 24V (*6 or 24V) 100Ah parallel connected batteries through solar charge controller and inverter. This way, We get the desired 12V, 24V or 48VDC system.

During the normal sunshine (day time) The solar panels charge the batteries (to store energy as backup power for later use in night/shading) and can power up the 24VDC load as well as 120V/230V AC load through automatic UPS wiring. The whole process is automatically done due to the use of Auto Inverter/UPS without using manual changeover/ATS switch system.

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