4 Signs You May Need to Replace Your Solar Batteries

Solar lights need a rechargeable battery, solar array, controller, and an LED bulb to function properly. Solar batteries store sun-generated power—a solar array or small photovoltaic cell is responsible for capturing sunlight during day light hours, and then the solar energy is converted into electrical energy. A ‘charge controller’ ensures that the batteries do not get overcharged and monitors the amount of light and turn the LED light on and off.

So, how do you know if you need to replace your solar batteries? Check the signs that would prompt you to replace your solar batteries below. 

  1. Solar Lights Turn on Using Regular Batteries

RedEarth Energy explains the importance of having good solar batteries for continuous illumination of your solar lights even during the cloudy days. That is why you have to regularly assess the condition of your solar batteries. You can easily check if the solar rechargeable batteries are faulty by replacing them with normal or regular batteries.

If your solar light doesn’t turn on at night as it is intended to, but it does turn on when you put in regular batteries, it means the issue is not with the bulb or another component of the light, but rather that the solar batteries are faulty or worn out. 

Note: Pay close attention to the solar light’s location, because solar batteries won’t charge properly when they are located in the shady area since they rely on the sun’s energy to charge. 

  1. Illumination Does Not Go Back to Normal After Charging 

After charging the solar batteries, the illumination of the solar lights should go back to normal. If not, you’ll need to replace the solar batteries.

Here’s how to test the solar batteries:

  • Place the solar lights under the sun for a day or two. Remember that solar lights must be exposed to direct sunlight for at least four hours daily to effectively charge the solar batteries.
  • Check if the illumination of the solar lights is back to normal.
  • If the light goes back to normal, it means that your solar panels were not getting enough sunlight, not that there was an issue with the batteries. 
  1. You Did Not Take the Solar Batteries Out

When storing solar lights during winter months, you need to remove the solar batteries to preserve their lives—otherwise, the batteries will die. If you tried testing the solar lights with the old batteries and they still don’t work even after charging them the whole day, you’ll need to replace the old batteries.

Here’s how to replace old solar batteries with a new set:

  • Remove the defective batteries from the solar lights.
  • You need to take the solar light apart if you cannot find a battery cover. Usually, you’ll see screws on the top or bottom of the lights where the batteries are placed.
  • Once you have accessed the solar batteries, you can now remove them and replace with new ones.
  1. You Tried Using the Batteries in Other Solar Lights but They Still Won’t Work

If you don’t have regular batteries, you can test the solar batteries by installing them to working solar lights if you have two or more of them. Make sure to fully charge the solar batteries for several hours in the other solar light before testing. If the other solar light works with the newly charged old solar batteries, then the initial solar light could be faulty. There are other issues that affect the solar power and illumination that solar lights produce, so the batteries are not always the culprits.

Choose the Best Rechargeable Solar Batteries

How many batteries do you need to make your solar garden lights work? Usually, solar lights need one to four batteries to work. The two types of solar batteries commonly used in garden solar lights include: AA size Nickel Metal Hydride (NiMH) 1.2 V /1000 to 2000mA; and AA size Nickel Cadmium (NiCad) 1.2 V / 500 to 900mA.

Check out the following benefits of different rechargeable solar batteries: 

  • Nickel-metal Hydride (NiMH) Batteries: They have up to three time more charging capacity as compared to Nickel-cadmium (NiCd) batteries. So, it means that they last longer and are more reliable. Also, NiMH batteries are better than NiCad because they are more eco-friendly and withstand greater temperatures. Even during cloudy days, NiMH continue to charge and their performance won’t diminish even with partial charges without the sun.
  • Nickel Cadmium (NiCad) Batteries: They are more affordable than NiMH batteries.


Solar battery performance can be affected by how much time you charge the solar batteries, the amount of sunlight available, and the lifespan of the batteries. Testing is required to fully assess if the solar batteries are indeed faulty or just improperly charged.