How long do solar lights stay ON at night?

how long do solar lights stay on at night

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If you are thinking of installing a solar light at home and wants to know about how long do solar lights stay on at night? than this is the right post for you.

In this post we will look at for how long a solar light can stay on during the night and what are the factors which affect its performance.

Short answer: On an average solar lights stays on for 8-10 hours in the night. But there a several other factors which directly affects the output from the solar lights.

These factors I have discussed in detail below.

1. battery

As we all know that solar lights are powered by rechargeable batteries which are pre-installed in them.

The battery installed in solar lights are AA batteries[1] and their capacity to store energy ranges from 400 mAh to 2750 mAh.

Higher the capacity of the battery means more room to store energy.

solar lights rechargeable battery ni-mh

In solar lights, manufacturers mostly use three types of AA batteries. These are nickel-cadmium(NiCd), Nickel-metalHydride(NiMH) , and Lithium-ion(Li-ion). There range also varies according to their chemical composition.

I have put the data in the form of a table to make it clear for you.

Chemical CompositionRange(mAh)
Nickel-cadmium(NiCd)600-1000
Nickel-metalHydride(NiMH)600-2750
Lithium-ion(Li-ion)600-840

2. Age of solar light, Panels, and battery

The second important factor in the right working of solar light is its age. As we are aware of this fact that every thing in this universe has a life span. So does a solar light!

When the parts of solar light like battery, pv panel starts ageing their work efficiency decreases and consequently the batteries will store less charge.

When less energy will be stored in the batteries than they will work for lesser number of hours.

3. position of solar lights

Third factor that plays an important role in lightening the solar lights is their correct placement.

A rightly placed solar light’s panel will be able to generate more electricity. I have a detailed article where I had talked about the direction of solar lights. You can read that too.

4. dirt on solar panels

This is the biggest factor after the battery one. You may know that air contains various particles like dust with it.

When this air blows through the solar panels, the dust particles embedded in the air starts depositing on the panels.

Gradually if left unnoticed this deposition of dust and other materials will convert into a thick layer. This thick layer of deposition will than obstruct the sunlight to penetrate the photovoltaic cells.

For a matter of fact in a study it is found that the presence of obstructing materials like dirt can reduce the photovoltaic performance by up to 85%[2].

So even if the solar light is installed in outdoor conditions but a layer of dirt is on the panel surface than expect it to perform low in energy generation.

Related: Why are only half of my solar lights working?

5. indoor/outdoor

The placement of solar lights also play a great role in determining how long they will stay on in night.

The solar lights works best if they are placed in outdoor conditions facing the sun. When placed indoors the first thing that will happen is the current will slash to one-third of the outdoor condition.

Less current means less charging. I have talked about it in my post about Can I charge solar lights indoors?.

6. no. of lED lights

The sixth and last factor on my list which can hugely impact the working time of solar lights is the number of LED lights installed in the product.

LED lights are used to actually give light. But if the product will have more LED lights then the capacity of the battery than the battery will drain out fast, even if the battery is of high storage capacity!

how to make solar lights stay on longer?

Now after looking at the factors which can hamper the performance of solar light it is time to know what things can be done to make them stay longer.

There are few things that you can do to make your solar lights stay on longer. These are:

1. install higher capacity battery

Most of the solar lights available in the market has the option for replacing the batteries.

So the first thing you can do is replace your solar light’s battery with a higher mAh one.

But make sure it has the same voltage rating as the previous one. With a higher capacity rechargeable battery you can expect it to work more.

2. place them in right direction

Second thing to do is place the light in the right direction and position.

As I have already talked above, the best positions for solar lights is facing south(north hemisphere) and facing north(southern hemisphere).

So try to place the lights in such places where sun rays can fall on them for maximum time of the day.

3. clean them regularly

Cleaning solar lights is as important as placing them in right position. Left uncleaned can hugely decrease their energy generation capacity.

So make this habit of cleaning them regularly. Fix a day of the week for removing the dust from the solar light’s PV cells.

do solar lights stay on all night? conclusion

Working of solar lights in the night depends upon the level of their charging during the day.

If they receive ample sunlight and have a good capacity battery than they can stay On for whole night. But if they are old their working hours will decrease.

You can check more about solar lights here: solar lights On time

references

  1. https://en.wikipedia.org/wiki/AA_battery
  2. https://www.sciencedirect.com/science/article/pii/S1876610214007425