Do Solar Lights Need Direct Sunlight? (How It Works)

Solar-powered lights work by taking available light and using that to charge the system so they can operate at night or if the power goes down. A wide range of these lights is available in both style and design. But the question is: Do solar lights need direct sunlight to charge them?

Solar lights don’t need sunlight as they can charge using light sources such as incandescent or LED lights, but sunlight is the best option to charge solar lights through the built-in PV panels as it gives them the most efficient charge and will have them run at optimum as well.

Sunlight provides the most intense light source available, but because the solar lights are smaller and don’t require a massive charge to operate like a PV system would, you can use other light sources to charge them  – so let’s take a look at some of those.

How Long Does It Take To Charge Solar Lights Using Sunlight 

Solar lights have small wattages ranging from as little as 1W to about 5W, and so their battery is relatively small and uses relatively little current to run, which is why they can operate for 8 hours or more under full charge.

On average, solar lights would take around 4-6 hours in bright sunlight to fully charge and then deliver 8 hours of operation at night on that charge. Under optimum conditions with clear skies, moderate temperatures, and bright daylight, solar lights will charge up faster than in cloudy or very hot conditions.

If the temperature outside is higher than 77℉, the less efficiently the solar panels will charge, so the optimum charging temperature is 77℉ or lower for solar panels, regardless of their size.

Can Solar Lights Charge Without Direct Sunlight 

Yes, they can. Even when the weather is cloudy or rainy, there is still some level of sunlight that reaches the earth’s surface, and this lower intensity of light will still charge your solar lights, although it will take longer.

Where the weather is really bad, and there is very little sunlight reaching the panels, you may struggle to charge and use your solar lights, so here are some other light source options you can use.

Charging Solar Lights Using Incandescent Bulbs 

Incandescent Bulbs 

Long before LED’s were thought of, Edison’s electric light bulb was the primary source of light in homes and businesses. Incandescent lights provide a good range of light from low to high wattage, and you can use an incandescent light source to charge your solar light.

Firstly, the higher the wattage of the lamp, the better. A 40W incandescent bulb will take twice as long to charge a solar light as a 100W bulb, so if you are going to use an incandescent bulb, try and find one with a high wattage.

The greater the rated wattage of the lamp is, the more light energy it will emit, which will enable your solar lights to charge faster and be ready for use. Remember that incandescent lamps are not that efficient as a lot of their energy is released as heat.

How to do it:

  • Place your solar light underneath the bulb but don’t put it too close as this will heat the solar PV panel, and the hotter it gets, the less effective it will be in absorbing that light and transforming it into electricity.
  • Have your solar light around 10 inches to 20 inches away to maximize the absorption of light and minimize the effect of the emitted heat. Depending on the bulb wattage, it would take about two hours longer to charge using incandescent light than sunlight.

Halogen Lamps Will Also Charge A Solar Light 


The old halogen floodlights or 50W downlighters emit a strong and varied frequency of light that could also be used to charge solar lights. The light intensity and wattage of halogen lights are similar to sunlight, but these lamps also emit heat.

If you will use a halogen light source, make sure that your solar light panel isn’t too close as it will heat up, so place it around that 20” mark away and then leave it to charge.

Give it about 30 minutes and then test how hot the panel is; if it is hot to the touch, move it further away to reduce the heat impact.

Can LED Charge A Solar Light 


As incandescent can charge a solar light, so can LED. Led emits light in the same spectra as the sun from infrared to visible and ultra-violet light. An LED floodlight would be a good start as the light intensity output from that fitting would be adequate for charging the solar light.

You could use any LED light source, from indoor lights to flashlights, and you would need around 10-12 hours to charge your solar light using LED. Of course, it would depend on the LED light source, so a 200W LED floodlight would charge your solar light a lot quicker than a 10W LED floodlight.

Because LED doesn’t emit nearly as much heat as incandescent lamps, you can have the solar light much closer to the light source to effect faster charging. Remember that nothing will charge your solar light better than the sun, but using LED will enable you to charge your solar lights so you can use them.

How To Use Mirrors To Charge Solar Lights 

Another option is to use mirrors to reflect light onto the solar light’s PV panel, which will start to charge the battery in the light. You can reflect sunlight or any other light source to fall onto the solar light’s PV panel.

If your solar lights are under shadows, this could be a good option to add some additional light energy and help to charge them faster.


We have established that you don’t need to have your solar lights in direct sunlight to charge them because the amount of energy they need is not that much, and so you can use artificial light sources to power them if need be.

Remember to keep your solar light panels clean, position them in direct light and away from shadows so they can absorb as much light energy as possible regardless of which light source you use to charge them.

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