Category: Solar

What is LiFePo4 Batteries

by blogadminSolarLeave a Comment on What is LiFePo4 Batteries
Table Of Contents−

Introduction

Sure, here’s the continuation of the article:

Introduction

LiFePo4 Batteries have gained significant popularity in recent years due to their exceptional performance and reliability. In this comprehensive blog, we will delve into the various aspects of LiFePo4 batteries, including their overview, advantages, disadvantages, applications, charging and discharging characteristics, comparison with other battery technologies, safety considerations, and maintenance and care. So, let’s get started!

Overview of LiFePo4 Batteries

LiFePo4, which stands for Lithium Iron Phosphate, is a type of rechargeable battery that belongs to the lithium-ion family. These batteries are known for their high energy density, long cycle life, and impressive thermal stability. LiFePo4 batteries have become a preferred choice for various applications, ranging from electric vehicles and renewable energy storage to portable devices and marine applications.

Advantages of LiFePo4 Batteries

One of the key advantages of LiFePo4 batteries is their enhanced safety compared to other lithium-ion batteries. They have a lower risk of thermal runaway, making them less prone to overheating or catching fire. Additionally, LiFePo4 batteries offer a longer lifespan, with a typical cycle life of 2000 to 5000 cycles, depending on the depth of discharge.

Disadvantages of LiFePo4 Batteries

While LiFePo4 batteries have many advantages, it’s important to consider their limitations as well. One of the main disadvantages is their comparatively lower energy density when compared to other lithium-ion battery chemistries. This means that LiFePo4 batteries may have a larger physical size and weight for a given energy capacity. However, advancements in technology are continuously improving the energy density of LiFePo4 batteries.

Applications of LiFePo4 Batteries

LiFePo4 batteries find applications in a wide range of industries. They are extensively used in electric vehicles (EVs) due to their high power density, fast charging capabilities, and long cycle life. These batteries are also utilized in renewable energy systems, such as solar and wind power storage, as they provide reliable and efficient energy storage solutions. Additionally, LiFePo4 batteries are commonly used in portable devices, like laptops and smartphones, as well as in marine applications for powering boats and yachts.

Charging and Discharging Characteristics

LiFePo4 batteries have unique charging and discharging characteristics. They can be charged at higher currents, allowing for faster charging times. Moreover, LiFePo4 batteries exhibit a relatively flat discharge curve, providing a stable voltage output throughout most of their discharge cycle. This makes them ideal for applications where a consistent power supply is required.

Comparison with Other Battery Technologies

When comparing LiFePo4 batteries with other battery technologies, such as lithium cobalt oxide (LiCoO2) or lithium manganese oxide (LiMn2O4), several factors come into play. LiFePo4 batteries offer better thermal stability, improved safety, and a longer lifespan. However, they have a lower energy density, as mentioned earlier. The choice of battery technology depends on the specific requirements of the application, considering factors like energy density, power output, and safety considerations.

Safety Considerations with LiFePo4 Batteries

LiFePo4 batteries are considered safer than other lithium-ion batteries due to their intrinsic chemical stability and resistance to thermal runaway. However, it is essential to handle and use them according to the manufacturer’s guidelines to ensure optimal safety. This includes using appropriate charging equipment, avoiding overcharging or over-discharging, and protecting the batteries from extreme temperatures.

Maintenance and Care of LiFePo4 Batteries

To maximize the lifespan and performance of LiFePo4 batteries, proper maintenance and care are crucial. It is recommended to store LiFePo4 batteries in a cool and dry environment, away from direct sunlight and moisture. Regularly checking the battery’s voltage and capacity can help monitor its health. Additionally, following the manufacturer’s instructions for charging and discharging can prolong the battery’s lifespan.

Conclusion

In conclusion, LiFePo4 batteries offer a range of advantages that make them a popular choice for various applications. Their safety, long cycle life, and compatibility with different industries make them a reliable energy storage solution. However, it’s important to consider their energy density limitations and follow proper maintenance practices to ensure optimal performance and longevity.

With this comprehensive overview, you now have a solid understanding of LiFePo4 batteries and their significance in today’s energy landscape. Whether you’re considering them for your electric vehicle or renewable energy system, LiFePo4 batteries are a promising technology that continues to revolutionize the way we harness and store energy.

How to make 12V 18650 battery pack for solar system

by blogadminSolarLeave a Comment on How to make 12V 18650 battery pack for solar system
Table Of Contents−

Introduction

Welcome to our comprehensive guide on how to make a 12V 18650 battery pack for a solar system. In this article, we will walk you through the step-by-step process of creating your own battery pack using 18650 batteries. Whether you are a DIY enthusiast or someone looking to power your off-grid solar setup, this guide will provide you with all the necessary information to get started.

Understanding the 18650 battery

Before we dive into the construction process, let’s take a moment to understand what exactly an 18650 battery is. The 18650 battery is a type of rechargeable lithium-ion battery commonly used in various electronic devices. It is known for its high energy density, long cycle life, and excellent performance. These characteristics make it an ideal choice for building a reliable and efficient battery pack for solar systems.

Choosing the right components for the battery pack

Now that we have a basic understanding of 18650 batteries, let’s discuss the components you will need to assemble your battery pack. Apart from the 18650 batteries themselves, you will require a battery holder or a battery case, nickel strips for interconnecting the batteries, and a battery management system (BMS) to ensure safe charging and discharging.

Preparing the 18650 batteries for the pack

Before we start assembling the battery pack, it’s essential to properly prepare the 18650 batteries. Begin by checking the voltage of each battery using a multimeter to ensure they are all at a similar level. Next, remove any protective wrapping or insulation from the batteries, being cautious not to damage the cells. This step will allow for better heat dissipation during operation.

Soldering the battery cells together

Now comes the critical step of soldering the battery cells together to form the pack. Start by aligning the batteries in a series or parallel configuration, depending on your desired voltage and capacity. Use nickel strips to connect the positive and negative terminals of the batteries, ensuring secure and reliable connections. Take necessary precautions while soldering to prevent overheating the cells.

Adding a battery management system (BMS)

A crucial aspect of any battery pack is the inclusion of a battery management system (BMS) to protect the cells from overcharging, overdischarging, and excessive current. The BMS monitors and balances the individual cell voltages, ensuring the overall health and longevity of the battery pack. It is recommended to choose a BMS that is compatible with your battery configuration and solar system requirements.

Connecting the battery pack to the solar system

With the battery pack assembled and the BMS in place, it’s time to connect it to your solar system. Ensure you have the necessary cables and connectors to establish the connection between the battery pack, solar panels, charge controller, and inverter. Follow the manufacturer’s guidelines and wiring diagrams to ensure a proper and safe connection.

Testing and troubleshooting the battery pack

Once all the connections are made, it’s crucial to test the battery pack and troubleshoot any potential issues. Use a multimeter to verify the voltage, check for any abnormal temperature rise during charging or discharging, and monitor the performance of the solar system. If any problems arise, refer to the manufacturer’s instructions or seek professional assistance.

Safety precautions and considerations

When working with batteries and solar systems, safety should be a top priority. Always wear protective gear, such as gloves and safety glasses, when handling batteries and while soldering. Ensure proper ventilation in the area where you are working and keep flammable materials away. Follow all safety guidelines provided by the battery and solar system manufacturers to avoid accidents or damage.

Conclusion

In conclusion, building your own 12V 18650 battery pack for a solar system is an achievable and rewarding project. By following the steps outlined in this guide and taking necessary safety precautions, you can create a reliable and efficient energy storage solution for your off-grid or backup power needs. Remember to regularly monitor and maintain your battery pack to ensure optimal performance and longevity. Happy solar system battery pack building!

And with that, we’ve reached the end of our comprehensive guide on making a 12V 18650 battery pack for a solar system. We hope you found this article helpful and informative. If you have any further questions or need additional assistance, feel free to reach out. Happy DIY-ing!

Growatt Inverter Client App – Java Client

by blogadminSolarLeave a Comment on Growatt Inverter Client App – Java Client

Java Client for the Growatt Inverter

This Java application currently supports 3 main actions.

A1) Notify when the grid voltage is 0v (i.e. Power cut)

A2) Change power input priority (SUB / SBU)

A3) Change battery charging priority (Solar Only / Solar Priority)

A1) Notify when the grid voltage is 0v (i.e. Power cut).

Currently, the Growatt mobile app does not have any notification mechanism to alert when the grid power goes away. This app uses an ugly hack to achieve that up to some level.

The application keeps polling (once every 5 minutes) the Growatt cloud and checks if the Grid voltage is 0v. If it is, it fires a configured Gmail webhook which sends a chat message to the user. Since the Datalogger only uploads data once every 5 minutes, we can’t get an accuracy higher than 5 minites even if we change the app to run more frequently.

This will also send a power status chat every day at 7 AM to let you know that the app is running properly.

Note: Please don’t use this action unless you really need it, as this introduces considerable traffic to the Growatt cloud.

A2) Change power input priority (SUB / SBU)

This can be used to change power input priority of the inverter automatically, based on a time schedule.

This is written as a test case so that it can be automated using a Git Action workflow. Have a look at the Github workflow files in this repo.

A3) Change battery charging priority (Solar Only / Solar Priority)

This can be used to change the battery charging priority of the inverter automatically.

This is also written as a test case.

How to run?

  1. Configure authentication details in the Configurations.java file.
  2. To run #A1, build the repo and simply run the main method of the Monitor.java class.
  3. To run #A2 manually, you can use the below command.
mvn clean install -P change-settings -Dtest="MonitorTest#testOutputChangeToSUB"

or

mvn clean install -P change-settings -Dtest="MonitorTest#testOutputChangeToSBU"

To automate #A2, create a private git clone of this repo (as you’re configuring your credentials in step 1). Change cron jobs based on your requirement.

  1. To run #A3 manually, you can use the below command.
mvn clean install -P change-settings -Dtest="MonitorTest#testChargingChangeToSolarOnly"

or

mvn clean install -P change-settings -Dtest="MonitorTest#testChargingChangeToSolarPriority"

 

Special Thanks to bhathiya/growatt-inverter-client

Sako Isun Inverter USB Driver + Monitoring

by blogadminLinux / SolarLeave a Comment on Sako Isun Inverter USB Driver + Monitoring

This is an Solar inverter monitoring and controlling system for hybrid inverters, Following are the main components in the system.

  • Solar Inverter driver program to communicate with USB serial port (Python)
  • Python Flask based REST API to expose the data
  • ReactJS based web portal (PWA) for monitoring and controlling the inverter

Tested Solar inverters

Currently we have tested this on Sako Isun 3KW.

Supported compute devices

  • Raspberry pi
  • Orange pi
  • Any Unix device

Hardware setup

  • Use the USB cable provided with the inverter or any appropriate USB cable
  • Connect the USB cable to any of the supported device
  • Install the pre-requisite mentioned in the following install steps
  • Run the tools/check-inverter.py script to connection between inverter and the compute device
  • For any issues check the Troubleshoot section

How it works

Most of the Hybrid(Chinees) inverters comes with the following Serial interface

Bus 001 Device 002: ID 0665:5161 Cypress Semiconductor USB to Serial

For this VendorID and ProductID there are several UPS and inverter devices using this serial com device. But this device had no drivers for Raspberry pi, So when the inverter is connected to a Raspberry pi(or similar) compute device , it detects as a USB block storage device

/dev/usb/hiddev0

not as a USB serial communication device.

i:e

/dev/ttyS0 or /dev/USB0

To establish communication between the inverter and the compute device we had to use pyUSB approach described in here. For the basic working principles of Inverter – Compute device (Raspberry pi) communication check the above article.

Another important piece of the puzzle was to find out the communication protocol. This document from a random generous Czech inverter site.

Without this, Decoding the values sent from inverter was a challenge

and the meanings of

  • QPIGS: Device general status parameters inquiry

and

  • QMOD: Device Mode inquiry

were like greek!

Once the communication is established it’s was just a matter of routing the data to client application (React app) to present the data.

We use Flask to implement REST API and ReactJS, MUI , React Query in the UIs.

Install

Most of the Raspberry pi & Orange Pi variations doesn’t come with pip pre-installed, Hence we have to run this

  • sudo apt-get install python3-pip

Install the Python USB communication library

  • python3 -m pip install pyusb

This is required for the following crc16 library

  • sudo apt-get install python3-dev

CRC16 is used to generate the 2 byte CRC, CRC is a way of detecting accidental changes in data storage or transmission

| Note: This only works upto python 3.9 versions, If you have a latest version of Python 3.10+, This will not work

  • python3 -m pip install crc16

Add a Udev rule as shown below, This is required to allow communicating with the USB device for none-sudoers users. Example file is given in

references/99-knnect.rules

in this repo

  • sudo vim /etc/udev/rules.d/99-.rules

Restart the Udev admin to apply the changes

  • sudo udevadm control –reload-rules && sudo udevadm trigger

Accessing from anyway

Currently this only support monitoring through the local network, If you want to monitor or control the device through internet, Then you need to expose the APIs through Choreo (It’s free) like API proxy service or Buy a Blynk subscription and publish data to blynk.

Troubleshoot

  • Use
sudo lsusb

to check whether the Serial Communication device has been detected by the operating system if so it show show as

Bus 001 Device 002: ID 0665:5161 Cypress Semiconductor USB to Serial

in the output of lsusb command

Special Thanks To (tmkasun/solar-hybrid-inverter-monitor)

Difference Between MPPT and PWM Charge Controller

by blogadminSolarLeave a Comment on Difference Between MPPT and PWM Charge Controller

 

MPPT Solar Charge Controller

 PWM Solar Charge Controller

1. What they do

The PWM controller is in essence a switch that connects a solar array to a battery. The result is that the voltage of the array will be pulled down to near that of the battery.

The MPPT controller is more sophisticated (and more expensive): it will adjust its input voltage to harvest the maximum power from the solar array and then transform this power to supply the varying voltage requirement, of the battery plus load. Thus, it essentially decouples the array and battery voltages so that there can be, for example, a 12 volt battery on one side of the MPPT charge controller and a large number of cells wired in series to produce 36 volts on the other.

As array size increases, cable length will increase. The option to wire more panels in series and thereby decrease the cable cross sectional area with a resultant drop in cost, is a compelling reason to install an MPPT controller as soon as the array power exceeds a few hundred Watts (12 V battery), or several 100s of Watts (24 V or 48 V battery).

PWM

The PWM charge controller is a good low cost solution for small systems only, when solar cell temperature is moderate to high (between 45°C and 75°C).

MPPT

To fully exploit the potential of the MPPT controller, the array voltage should be substantially higher than the battery voltage. The MPPT controller is the solution of choice for higher power systems (because of the lowest overall system cost due to smaller cable cross sectional areas). The MPPT controller will also harvest substantially more power when the solar cell temperature is low (below 45°C), or very high (above 75°C), or when irradiance is very low.

  • Charging Method
    The difference between the PWM controller and the MPPT solar controller is that they charge differently. The PWM is charged in a three-stage charging mode. MPPT is the maximum power tracking technology, and the charging efficiency can be increased to about 30%.
  • Voltage
    When the MPPT solar controller is used, the charging efficiency is more obvious when the high-voltage solar panel is used to charge the low-voltage battery. If the voltage of the solar energy and the battery are the same, for example, it is 12V, then the difference between the practical PWM and the MPPT controller is not very big.
  • Power
    If the power of the solar panel is small, it is more appropriate to select a PWM controller. Relatively speaking, if the power of the solar panel is large, MPPT is selected.Solar controllers, because the cost of MPPT solar controllers is high, if your solar panel power is small, it is a waste of MPPT controller.