Most solar inverters nowadays come with built-in solar charge controllers, whose primary function in on-grid and off-grid solar power systems is to charge batteries that are attached to the system. These solar charge controllers within the solar inverter ensure that the connected batteries are not damaged through overcharging, and also protect the battery from discharging back into the solar panes during low sunlight. Sometimes the problem may arise in any of the components of the solar system that don’t charge the batteries. This article will cover troubleshooting these problems.
How to Troubleshoot Battery Charging Problems in a Solar System
There are many techniques to determine whether or not the solar panel is properly charging the batteries including inspecting battery, solar panel, solar charge controller, and wiring. All these techniques have been covered in detail as follows:
1. Inspecting Batteries
First, check and determine if your battery is properly connected. If the battery has internal or external corrosion, it may hinder the charging process. Battery connections may also arise if the cables connecting the solar panels to the battery connections are unfastened. Moreover, troubleshoot any of the below three common issues found in battery:
a. Over Discharged Battery
If the battery is fully drained, it must be recharged before the solar charge controller can start charging it. This may be accomplished by connecting the battery to a boost charger via mains or a generator. In boost charging a boost voltage (slightly higher than float voltage) is applied temporarily to the battery to regain its charge status.
b. Faulty Battery
A solar battery that is damaged or broken cannot be recharged. Furthermore, charging the whole battery string will also fail if even one of the batteries is compromised. The best approach to troubleshooting this problem is to locate and replace the damaged battery immediately.
c. Weak Battery
Check whether the design of the battery capacity is appropriate; if the capacity is insufficient, the run time will be short. Also, if the battery comes to an end-of-life then its performance will go down. Check the manufacturer’s datasheet for the number of cycles and calculate the battery’s end-of-life. Moreover, short circuits during the installation process will also weaken its charge-retaining capacity. In all three of the above cases, the battery should be replaced with a new one.
2. Checking Solar Panels
If the solar panels are not generating enough power, then they will not charge the batteries. Therefore, it is necessary to regularly check solar panels for any defects or damages and also make sure their voltages are within the required ranges. Below are the common solar panel faults that can hinder the charging process with their troubleshooting techniques.
a. Dust, Dirt & Snow on Solar Panels
Solar panels are dependent on sunlight absorption through their surface. The air quality can affect this absorption. In the summer season usually, dust and dirt deposit & in the winter season particularly snow accumulates on the surface of solar panels. The output power producing ability of solar panels significantly reduces if dirt or snow gathers on its surface. Therefore, regularly clean the solar panel’s surface to ensure that they are operating at peak efficiency.
b. Voltage of Solar Panels
Solar panel’s output voltage is an important factor in charging the batteries. Three types of voltages should be considered for checking the performance of each panel:
- Nominal Voltage
- Voltage at Open Circuit (VOC)
- Voltage at Maximum Power (VMP)
Open circuit voltage is measured across each solar panel when no load is connected. Maximum power voltage is measured across each solar panel when the load is connected and is operating at its peak rating. To check the voltage connect a multimeter with the solar panel’s output pins and point them towards the sun. The multimeter’s reading should match the standard voltages of 12V & 24V solar panels as shown in the table below. If the voltage does not match, then panel replacement is required. Always refer to the manufacturer’s datasheet for specific voltages:
|
# of Cells in Series |
Nominal Voltage |
VOC Typical |
VMP Typical |
|---|---|---|---|
|
72 |
24 |
42 |
35 |
|
36 |
12 |
21 |
17 |
c. Fault In Solar Panels
Although most reputable brand solar panels come with 25 years of warranty which corresponds to their durability and long life. However, sometimes they may get some faults that can be examined physically. When a solar panel is partially covered with shadow or darkness, hotspots appear in the shadowed or darkened part. Due to hotspots temperature in the shadowed part becomes higher than the other part of the panel that receives full sunlight and can damage the cells. Moreover, cracks can also appear in the solar panel which accelerates the decay and lowers its lifespan.
Both hotspots and cracks lower the overall efficiency of solar panels and don’t deliver the desired power, thus battery charging issues arise. This problem can be easily resolved by physically inspecting the solar panels regularly. Remove any shadow or change the placement of the solar panel for direct sun exposure, this will resolve hotspot problems. Moreover, for cracks issues, contact the solar panel manufacturer for warranty claims to replace them.
3. Checking Solar Charge Controller
A malfunctioning solar charge controller might potentially prevent the battery from being charged. The modern solar charge controllers come built-in within the solar inverter package. Whether built-in or separate, solar charge controllers can be fixed easily. Pulse width modulation (PWM) and Maximum power point tracking (MPPT) are two popular types of solar charge controllers available. They are equipped with various error display options. If a malfunction is identified, the device will begin beeping or flashing lights on the front panel.
Follow these steps to check and troubleshoot solar charge controller problems:
- First, confirm the amount of current and voltage coming from the solar panels on the LCD panel.
- Then, calculate the amount of current and voltage required by the batteries installed.
- If the displayed current and voltage doesn’t matched the batteries requirement, then the solar charge controller circuit has a fault and needs to be replaced.
Conclusion
Batteries are a great way to store charge in the solar system that can be utilized in case of power shutdown. Sometimes, the solar panels are not able to charge batteries and this problem can arise anywhere in the solar system. This article has covered all the technical problems with solar panels not charging batteries. Their effective troubleshooting techniques have been given in detail. Hope that your troubleshooting skills will enhance after reading this article. Nevertheless, it is highly recommended to read the manufacturer’s user manual of all components before doing any troubleshooting task and contact your solar service provider for further technical assistance if the problem persists.
