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Why Do Solar Lights Need Batteries? [Are They Necessary?]

Tim Carter
Written by Tim Carter Last Updated: June 12, 2022

You can purchase solar lights in different shapes and sizes, and one of their advantages is that they don’t need to be plugged into a socket because they generate power from the sunlight via solar photovoltaic cells (solar panels). Yet, they need batteries to work when you need them to work – from dusk till dawn. But why do solar lights need batteries?

Solar panels cannot make electricity without direct sunlight, but solar lights need a source of power to work at night. Solar panels create electricity during the day and store it in batteries that your solar lights use to light up your gardens, porches, entrances, driveways, and so forth.

Is it possible to create energy from the moonlight using solar panels? Do we really need batteries?

Solar panels can convert moonlight into electricity.

However, enough electricity cannot be generated from solar cells during the full moon because of the limited amount of energy available.

A solar panel that generates 3450 W at noon might only produce 10 W during a full moon.

In other words, moonlight cannot generate enough power to keep your lights running for the whole night, so solar lights need sun’s energy to charge.

Table of Contents

Why Do Solar Lights Need Batteries?

Sunlight reaches the earth and falls onto solar panels. Solar panels then turn the light of the sun into electricity that you can use immediately or store in batteries for later use.

To store energy, your solar-powered lights need rechargeable batteries. So, when it’s time for them to light up your garden, patio, or entrance, they will shine by consuming the energy stored in the batteries.

Therefore, solar panels cannot generate the power of the sun during the night, and your lights still need a power source.

Related: Do Solar Panels Work With Moonlight? [Or They Need Direct Sunlight?]

How Do Solar Lights Work?

Let’s see how do solar garden lights work.

You might have noticed that your solar lights have a small solar panel, most likely on the top of the unit. This is because solar panels need maximum exposure to direct sunlight.

This small panel on your lights is a tiny version of large solar panels you can see on house roofs.

All solar panels have photovoltaic cells (PV cells) housed between semi-conductors. A solar panel works only as sunlight (photons) hits its surface and starts a physical process that creates electricity.

Now, if you are using a large solar panel or a whole solar system, you can use that electricity instantly to power your gadgets and appliances. But normally you wouldn’t need lights turned on throughout the day, especially in your garden or your porch.

We need lights when it’s getting dark and throughout the night. And solar panels cannot generate electricity without the power of the sun.

So, instead of having your lights plugged into a wall socket to shine, you will have them illuminating your area by consuming the power stored in the rechargeable batteries.

What Type of Batteries Do Solar Lights Use?

The batteries within solar garden lights are always rechargeable.

Normally, solar-powered garden lights use either lithium-ion batteries (installed in high-end solar garden lights such as security lights), nickel-cadmium (NiCd) rechargeable batteries, or nickel-metal hydride (NiMH) rechargeable batteries.

When night comes, a sensor tells the solar light to switch on, and then they use the energy stored in the batteries.

Do I Need To Change the Batteries in Solar Lights?

Commonly, outdoor solar lights stop functioning because rechargeable batteries inside them have simply worn out.

So replacing old rechargeable batteries in your solar lights every year or two is a great idea.

You need rechargeable batteries in your solar lights, as the solar panel converts the sunlight into power to charge the batteries, which power the light.

Almost all garden solar lights use low-capacity rechargeable batteries. More recently, solar lights will use 1.2V NiMH (Nickel Metal Hydride) batteries. These newer NiMH batteries replace the old-style NiCd ones.

What Batteries Should I Use in My Garden Solar Lights?

There are different sizes (AA, AAA) and capacities of rechargeable 1.2V NiCd and 1.2V NiMH batteries.

There are a few other, less popular, and harder-to-find sizes and capacities.

Before you purchase new rechargeable batteries for your solar lights, check out which someone originally installed ones and buy ones with the same voltage and similar capacity.

What Are the Best Replacement Batteries for Garden Solar Lights?

It’s important that you replace the batteries you take out of the solar lights with the same voltage and similar capacity.

You can check the capacity of your old batteries (in a mAh rating) and replace them with a different mAh capacity, as long as they are the same voltage.

Also, don’t replace old batteries with a much higher battery capacity.

Can You Use Regular Batteries In Solar Lights?

Standard alkaline batteries are not the greatest choice for solar lights.

Standard alkaline batteries may be used in solar lights when absolutely necessary, but since they can’t be recharged, standard batteries might cause a lot of problems and damage your lights.

As a result, having extra NiMH and NiCd batteries on hand is a good idea.

The first thing you’ll want to consider is the size of the battery.

Solar lights come in a variety of sizes, so it’s important to choose a battery that will fit properly in your light. The most common size for solar lights is AA, so that’s a good place to start.

Once you’ve determined the size of the battery you need, it’s time to think about capacity.

A higher capacity battery will last longer before needing to be replaced, so it’s a good idea to choose one with a high mAh rating. This will ensure that your solar lights stay shining brightly for as long as possible.

You can look at the capacity of your old batteries (in a mAh rating) and replace them with another mAh capacity, but they have to be the same voltage.

Final Thoughts

In conclusion, solar garden lights need batteries to work during the night because solar panels cannot produce electricity without direct sunlight.

During the day, solar panels generate electricity and store it in batteries.

Just as with any other gadget or appliance, your solar lights need a source of power to work.

In this case, this source of power comes from a rechargeable battery.


Tim Carter
Tim Carter

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