Wiring Batteries in Series and PV Panels in Parallel – 24V Installation
While most of the domestic PV panels installation are in 12VDC systems, there are cases where we need 24V or additionally 36V, 48V and so on depending on the system requirements.
Moreover, we need to connect the solar panels in parallel while batteries in series due to the system rating and specific environment. For example, If we have 24V solar panels as well as inverter and charge controller while the available (economically) batteries rating is 12V. We then connect the batteries in series to obtain the 24VDC system with all the related equipment related to the 24V system.
In this scenario, we will have to connect the 24V PV panels in parallel while connecting the 12V batteries in series. In this case, we will get the following electrical quantities having different ratings for both series connected batteries and parallel connected solar panels as follows.
Solar Panels in Parallel
The two parallel connected solar panels each have 24VDC, 5Amp and 120W. Current is additive in series connection while voltage is the same in each section. Additionally, Current is different in parallel while voltage is the same in each branch in parallel connection. This way,
Current in Parallel Connected Solar panels
I1 + I2 + I3 …… In
5Amp + 5Amp = 10Amp.
Voltage in Parallel Connected Solar Panels
V1 = V2 = V3 …… = Vn
24V = 24V
Batteries in Series
Similarly, the batteries have inversely connected as compared to the solar panel connection i.e. batteries are connected in series. Suppose the batteries rating are 12V, 100Ah. In this case,
Current in Series Connected Batteries
I1 = I2 = I3 …… In
100Ah = 100Ah
Voltage in Series Connected Batteries
V1 + V2 + V3 …… + Vn
12V + 12V = 24V
Caution: Both the batteries and solar panel must be having the same Ah (Ampere-hour) and voltage levels respectively while connecting them in parallel or series connection. In simple words, Do not connect a 12V battery with a 6 V battery in series or parallel. Similarly, don’t connect the 12V solar panels with 24V solar panels in parallel or series.
Good to Know: Batteries connected in Series will only add up the level of voltage and the Ah capacity remains the same. Alternatively, The battery storage capacity in Ah can be doubled (100Ah + 100Ah = 200Ah) by connecting them in parallel where the voltage level remains same i.e. 12V.
By following the above wiring configuration, we get the desired 24V system for all the solar panel system components.
The following wiring diagram shows that the two 24V, 5A, 120W solar panels connected in parallel will charge the two 12V, 100Ah batteries connected in series through the charge controller. Additional 24VDC load can be directly connected to the charge controller (DC output terminals).
During the normal sunshine/day, the solar panels can feed-up the power supply through an inverter and Auto UPS Wiring to the AC loads. During night/shading, the AC load can be powered-up through batteries (stored energy as backup power) as the batteries are connected to the inverter input as well. The whole process can be done automatically without using changeover/ATS switch or manual ON/OFF operation due to the auto operation of Inverter/UPS.
- A Complete Guide about Solar Panel Installation. Step by Step Procedure with Calculation & Wiring
- How to Design and Install a Solar PV System? With Solved Example
- Blocking Diode and Bypass Diodes in a Solar Panel Junction Box
- Basic Components Needed for Solar Panel System Installation
- How Much Watts Solar Panel You Need for Home Appliances?
- Solar Panel Wiring and Installation Diagrams