Solar Lights – Panel Battery/Direct Current

Some solar-powered lights come as an integrated unit with a small solar panel to charge the internal battery in the light. If the battery in a solar panel light dies, can it be powered without a battery?

Another question people often ask is whether light can be connected directly to a solar panel.

We will take a look at the following topics to answer these frequently asked solar questions.

  • Do solar panel lights need a battery?
  • Why do solar panel lights need a battery?
  • Can you connect a light directly to a solar panel without a battery?
  • How to connect a light to a solar panel.

Many people mistakenly think that electricity generated by a solar panel can be used directly from the panel itself. After all, if the panel is generating power, why can’t we use it. Solar panel power is “dirty” power that must be cleaned before we can use it effectively.

Solar lights on grass

Can A Solar Panel Light Work Without A Battery?

Solar power lights cannot be used without a battery to store the electricity generated during the day by the solar panel for use at night. Without a battery, there is no means to store the energy for later use once the sun has gone down.

Solar panel lights are most often in the format of outdoor lights, such as garden lights or security lights mounted on the exterior walls of your home.

These lights have a solar panel built into the construction of the light, which takes energy from the sun during the day. These lights also have a rechargeable battery built into the unit.

The energy from the solar panel charges the battery to restore it to full charge during daylight hours.

These solar panel lights generally have a day/night sensor built into their electronics, which allows the light to detect when night falls and automatically turn on the light.

Why Do Solar Lights Need A Battery?

Solar lights are intended to be illuminated at night when they provide a useful function of lighting up dark areas of your property or around your home. The battery stores the daytime solar energy for use at night to power the light.

Generally speaking, the time of day that the lights are most useful is in the dark hours of the night. At these times of day, there is no sunshine to activate the photovoltaic cells of the solar panel and generate electricity.

Consequently, for the lights to operate in the dark of night, the electricity generated must be stored somehow to power the lights once the sun is no longer in the sky.

Battery Storage

The best way to achieve this energy storage is with a battery. The solar panel in the light slowly charges the internal battery throughout the day.

Generally, a minimum of 6-hours of sunlight is required to fully charge the battery.

The reason the recharging process takes so long is due to the small size of the solar panel built into the structure of the light.

A larger panel will charge the battery faster, which is why some solar panel lights are being manufactured with a separate solar panel.

This type of construction allows the solar panel to be larger because its size is not limited by the physical size of the light. These solar panel lights will charge much faster in good sunlight conditions.

What Happens If The Battery In Your Solar Light Dies?

If the battery in your solar panel light dies, you will need to replace the batteries in the light with an appropriate rechargeable battery to replace the defective battery.

The light cannot function without the storage capability of the battery.

Rechargeable batteries have a limited duty cycle and will eventually deteriorate to the point that they need to be replaced. The constant depletion of the battery’s charge and the recharging of the battery takes its toll on the chemical composition of the battery.

Its efficiency at receiving a full charge and holding that charge will slowly diminish.

You will know that the battery in your solar panel light is near the end of its useable life when it takes longer to charge, and when the light comes on, the battery does not last the night, and the light goes out.

The light will also have a diminished brightness with a battery that is not operating at full capacity.

Batterries

Most solar panel lights have a battery compartment at the back of the light to replace the defective batteries. The size of the batteries in the light will depend on the size of the light.

Most garden solar lights will use rechargeable batteries in the AA or AAA size range.

Some solar panel lights require a screwdriver to open the battery compartment. Open the battery bay, remove the defective batteries with new rechargeable batteries of the appropriate size.

Do not use normal batteries in a solar panel light! These batteries are not intended to be recharged, and they could cause a fire or explode if you put them in a solar panel light.

Solar light in a garden with the sun shining

Can The Light Be Powered Directly From The Solar Panel?

A light cannot be powered directly from a solar panel. The voltage from the solar panel is not stable enough to power the light effectively.

As the voltage fluctuates, the light will dim and get brighter, and if the solar panel generates a spike, the light can be damaged.

Solar panels do not generate clean power. The energy level fluctuates with the amount of light the panel receives. If a cloud passes in front of the sun or a shadow falls on the solar panel, the panel’s energy output will drop.

Power Drops

As the sun becomes higher in the sky, the solar panel will generate a large amount of energy, and as the sun begins to set, the amount of energy the panel produces will drop.

This fluctuating energy makes it impractical to attach a light directly to a solar panel. Another device is required between the light and the solar panel to clean up the dirty energy produced by the panel.

How To Connect A Light To A Solar Panel Without A Battery

There is no efficient way to connect a light to a solar panel. However, it can be done with a DC-DC converter to clean up the panel’s energy output.

Once the voltage generated by the panel drops below the required input from the converter, the light will go out.

A DC-DC converter is a device that takes s DC voltage and outputs a constant DC output voltage.

For example, a DC-DC converter with a 48-volt input to 12-volt output will clean up the 48-volt input from minor fluctuations and deliver a constant 12-volts output.

The disadvantage with a DC-DC converter is that once the input voltage drops below the rated input of the unit, it cuts off the output power, and the light will go out.

References

General Solar Panel FAQ

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