Solar Charge Controller Keeps Blinking/ Flashing: Reasons and Fixes

Let’s say ‘curious you’ are inspecting the brand new solar-powered system you just installed. You come across your trusty Solar Charge Controller. But you begin to witness a bunch of lights flashing or blinking here and there. What’s happening? Solar Charge Controller blinking can indicate either normal processes happening or something went wrong.

If a warning light is blinking on the Solar Charge Controller, it may be due to faulty wiring, battery over-charging or under-charging, or equipment failure. So you have to make sure your system is properly wired, your equipment is up to date, and your battery is being charged properly.

So how do you make sure what is happening and take the necessary steps? Fear not, I will walk you through the process and provide you with all the crucial info. Without further ado let’s delve into the topic.

Solar Charge Controller Icons and Meaning

Let’s deal with the basics. Here we will learn about what most of the lights in your Solar Charge Controllers mean.

  • Panel Icon: As usual this oftentimes indicates the connection of your system with the Panel. If something goes wrong here you have to put the blame on the Panel Wiring or other pieces of equipment. When the charge controller gets power from the panel, this icon starts to flash and it stays stable and lit up. This means your system is Good!
  • Battery Icon: Simply like the previous point, this shows you the status of the Battery. If you face a problem here, your battery might be in danger. Depending on your Charge Controller, the Battery Icon flashing fast usually means your battery is fully charged. The opposite slow flashing means your battery is losing power. 
  • Load Icon: This is the load you put on your PV system. This icon lets you know if it’s big, small, or perfect. Depending on the Charge Controller, Light Blinking here means Overloading and Short-circuit. 

All of these may vary depending on the type of Solar Charge Controller you have. The key point here is the basic introduction. In the next two sections, we will learn in detail the reasons for the Solar Charge Controller Blinking / Flashing and what necessary steps to take in case of a problem.

Reasons for Solar Charge Controller Blinking

In this section, I have attached some of the most common reasons for Flashing/Blinking in Solar Charge Controllers.

Wrong Wiring

The classic issue. Wrong wiring is the single most common issue of many problems related to Solar Panels. First of all, if your panel is properly wired the charge controller would detect stable power input from the Solar Panel. The panel icon should stay stable. If it’s unstable, this icon will flash to warn you. If this is the case, it’s time to properly wire your system and troubleshoot issues with equipment.

Battery is Overcharged

Don’t you hate it your battery gets more energy than it can handle. This overcharging will cause damage to your battery. When overcharging occurs the battery icon would flash to alert you. In this case, It’d be a good idea to stop charging for now.

Battery is Undercharged

Just the opposite situation of the previous one. Similarly to Overcharging, Undercharging will also damage your battery. The charge controller will flash to alert you. One of the main reasons for undercharging is the lack of sunlight in the panel. So the fix would be to make sure the panel produces enough energy.

Indicating the Process of Bulk, Float, or Equalization Charging

Bulk, Float, and Equalization Charging are normal processes. Depending on the model of your Charge Controller, blinking may indicate one of these processes may be ongoing. No need to be scared since this is all-natural. 

Note: Any Blinking that is meant to alert will be different from regular blinking. (I.e. Red Light Blinking almost always means something is wrong with your system)

Faulty Equipments

Using old, worn-out, or faulty equipment is a surefire way to get problems. If you have problems isolating the problem correctly by trying out all of the above steps, the issue might be some random unknown faulty equipment.  

Fixes for Solar Charge Controller Battery Blinking

It’s time to fix all the issues we encountered. I’ll be listing all the necessary steps you should take. 

Fixing Wiring

  • Step 1: Turn off the whole system. (You don’t want to get electrocuted? Do you?)
  • Step 2: Check the wiring between your panel, charge controller, and battery. See any damaged wire? Fix or Replace them ASAP! Make sure you have connected the terminals properly (Hint: Consult your Instruction Manual for Help)
  • Step 3: Are your connectors loosely connected? Make sure the connectors are connected tightly. 
    Step 4: Check the Junction Box of the Solar Panel. Check the solders, and make sure there is no broken circuit.
  • Step 5: If your problem persists it’s highly recommended to get in touch with an expert and let the expert wire your whole solar-powered system

Fixing Battery Overcharging

One easy way to fix this issue is to put a regulator between the solar panels and the controller. It would control voltage and current and prevent overcharging. Another thing is to check if your battery is compatible with your solar panel PV system, and Solar Charge Controller. Incompatibility can cause Overcharging, so be sure to use compatible batteries.

Fixing Battery Undercharging

First thing first, go check if your panel is receiving enough sunlight. You don’t want low power coming into your panel due to some random tree obstructing sunlight. Then make sure your solar panel is clean, otherwise, dust will contribute to low power production which will lead to Undercharging. Also, be sure to use a good solar panel and a good battery because bad equipment always causes problems.

Replace Bad Equipment

It’s highly recommended that you replace old and rusty equipment with new up-to-date ones. Things like broken panels, old models of charge-controller, batteries in bad condition, etc. should be replaced. It’d fix a lot of issues, especially the Solar Charge Controller blinking and flashing due to some malfunction.

Take Help from a Professional

Is the problem still persisting, even after trying all this fix? It’s highly recommended to call up a professional. A professional helping you on the spot can easily troubleshoot problems. Problems tend to differ from person to person. A professional is way better in this case compared to a generalized guide.


A Solar Charge Controller flashing or blinking can easily seem intimidating to a newcomer. But with proper knowledge of the Charge Controller, a lot of things will be clear. (Pro-tip: Always read the Instruction Manual for proper knowledge)

Overall, Charge Controller Blinking means a natural process is happening most of the time. But if the Blinking is different (i.e. Red Light is a big indication of trouble), it is mostly due to Faulty Wiring, Battery being Over or Undercharged, or Bad Equipment. After identifying the problem, you have to take the necessary steps.