5 Solar charge controller problems (What Causes Them?)

In a typical solar system, power from the solar panels is fed to the batteries via a solar charge controller. However, this does not always work out.

If you see that solar power is not reaching your battery, it could be a sign that there is an issue with the wiring. This could indicate that there is an issue with the solar charge controller. This is likely to be the case if the system is relatively new.

To understand if there is a problem with the solar charge controller, you need to understand the most common problems that face these devices to make a correct diagnosis.

How Do I Know If My Solar Charge Controller Is Bad?

To conduct a full diagnosis, you will need a multimeter to test the entire solar system. That means you will test the solar controller, battery, solar panels, and other components.

To do this you will have to disconnect the solar panel from the system and measure the voltage output as the sun shines. If the sun is shining, there should be output panels.

If there is no voltage, it could be a sign of dirty panels.  Besides that, it could be a sign of problems with the rectifier diode.

Additionally, you need to measure the battery bank voltage. If the battery terminal voltage is less than 20% of the nominal voltage, it is a sign that you need an extra charger to charge the battery bank.

You will also need to measure the terminal output voltage of the solar charge controller and check whether the output is within the manufacturer’s range.

If out does not reach this range, it is a sign that the charge controller has problems.  You can try to fix the issue by replacing the charge regulator.

You will also have to check the solar batteries. Measure the battery capacity to ensure that the battery voltage is not too high or too low.

How Do You Reset A Solar Charge Controller?

Solar charge controllers protect the battery bank from damage by excess voltage. However, things could go wrong.

When this happens, it can be frustrating when you are unable to utilize your solar system to power your home. To deal with this issue, one of the steps you can take is to reset the solar panel charge controller.

To reset an MPPT solar charge controller, you only need to take a few simple steps. Most solar charge controllers come with four buttons.

To reset the device, simply hold all four buttons at once for 15 seconds, and it will reset. If that does not work, you can perform a hard reset.

This will entail disconnecting all four wires at the back of the solar charge controller. After that, wait for 20 minutes and reconnect the battery wires first and then the solar panel wires.

Why Is The Charge Controller Not Charging?

If a solar controller suddenly stops sending power to the batteries, it might be because of a few issues. We have a guide on why your solar charge controller is not charging the battery. Some of the common causes are:

Direct Charge Protection Point Voltage

Direct charge or rapid charge is a fast charge process that can be experienced by a solar system.

When the battery is charged with a high current and high voltage when the battery capacity is low. There is a control point known as the overcharge protection point.

When this point is reached, the charge controller cuts off the power supply to the battery to avoid overcharging the battery bank.

Equal Charge Control Point Voltage

Once the direct charging is done, the battery remains statically set by the charge controller for a time. When it falls to the recovery voltage state, it will enter an equal charge state. This takes a few minutes to equalize power in the battery.

Floating Charge

The floating charge, or trickle charge, is used to keep the battery charge since it will slowly discharge over time. It is a highly scientific process that involves lowering the charging current to prevent excessive outgassing because of overcharging.

Over-Discharge Protection Voltage

This is used to protect the battery from discharging below its stated value by the battery manufacturers.

Both the MPPT solar charger controller and the PWM solar controller have this protection. If you have long-term demand for solar power, an MPPT solar controller is the best option.

Check the Batteries for Issues

Sometimes, the problem is not with the solar controller but with the battery bank itself. Some of the common issues with batteries are:

Low Battery Capacity

Sometimes, the battery capacity may be too low to store enough solar charge. If that is the case, then you need to consider expanding the size of your battery bank.

Old Battery

In some cases, an old battery is unable to handle the demands of storing solar charge. While a battery can last up to 10 years, you need to check it often and consider finding a replacement after around 3 years if you notice a significant drop in performance.

Short Circuit

During the installation process, the battery may experience a short circuit. When that happens, the damaged battery will need to be replaced since its capacity will be affected.

Low Battery Capacity

When the battery bank has been left uncharged for a long time, it is hard to charge it using a solar system. To charge it, you might need to charge it using a high current.

It can then be returned to the battery bank to continue charging as normal. To improve the performance of the battery bank, consider adding a battery balancer.

Faulty Battery

If a battery in the battery bank is damaged, it will keep the entire pack from achieving full capacity. It is important to test batteries individually and replace any that have been damaged.

5 Common Problems with a solar Charge Controller

In general, the main problems of a solar charge controller are:

1. Low Battery Voltage

When the battery voltage is low, the controller turns off. To fix these issues, use an AC charger that will charge the battery to fill it up.

2. Load Output is Over-Current

When the load output is over-current, the charge controller switches off the load.

The solution is to decrease the load and use the minus button to turn on the load or the load will be automatically switched back on after 20 minutes.

3. Load Output short Circuit

When there is a load output short circuit, the controller switches off the load. The solution is to remove the short circuit failure of the load and use the minus button to turn on the load.

4. Battery Voltage is Too High

When the battery voltage is too high, the charge controller will switch off the load. The solution in this instance is to check whether the battery connection cable is loose.

You can also check whether the battery capacity is too small, and also check if there is another charger connected to the battery.

5. Output Current from Solar Panels Exceed Rated Current

When the solar panel output current exceeds the stated current, the charge controller will shut down. If that happens, you should check whether the solar panel array is overpowered. You can then decrease the connected panels, and the charge controller will begin charging.

Final Thoughts

Solar system owners should carefully examine their solar charge controller. A solar system only consists of solar panels, batteries, and the solar charge controller as its core components.

For you to enjoy the full benefits of solar charge, it is important to understand how all of these components work. It will help you monitor the solar system and make a prompt diagnosis before an issue gets worse.

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