Solar Energy Hackers

How to Choose the Best Solar Lights in 2020

how to choose the best solar lights

Thinking of switching to solar lights? Need to learn more about solar lights and how to choose the best one in the market?

If you answered yes to all these questions, then you better pay attention.

As you probably know, the process of choosing and comparing products can be really overwhelming, especially if you are new to the whole solar powered lights market.

However, we are here to make your life much easier. In this article, we will teach you all the insider tips that you need to know in order to pick the best solar lights out there.

So without further ado, let’s jump right into it.

1. Type of Bulb

There are more than 20 bulb types available in the market nowadays. However, the most common types are: Incandescent lights, Compact Fluorescent lights (CFLs), and LED lights.

Although both of them are great, LEDs are much popular because of how energy-efficient they are.

All of them come in various shapes, colors, and sizes that will suit all your needs.

Here is a quick comparison table between LEDs, Compact fluorescent lights (CFLs), and Incandescent lights:

Light Emitting Diodes (LEDs)Compact Fluorescent Lights (CFLs)Incandescent Lights
Use 75% less energy than incandescent lights
Use 70% less energy than incandescent lights
Not energy efficient
Last up to 25 yearsLast up to 10 years and contain traces of mercury.
So you need to properly dispose of them
Last about a year
High initial cost
Medium initial costLow initial cost
Don’t get hot to the touchDon’t get hot to the touchCan get really hot
Comparison table between LEDs, CFLs, and Incandescent Lights

2. Bulb Size

Choosing the right bulb size is really important. There are various sizes and each size has different uses. 

For example, if you are using solar string lights, you need your bulbs to be small and bright (C3:C5). On the other hand, if you are using solar spotlights, then you should opt for bigger bulbs (C7:C9).

Note: Make sure to choose solar lights with easily replaceable bulbs.

3. Solar Panel Type

As mentioned before, solar lights contain small solar panels. However, not all panels are alike.

There are various solar panels with different efficiency and life span. 

As a general role, the best solar panels should have:

  1. High conversion efficiency
  2. Sturdy shield cover
  3. Long life span and warranty

Here are the most common types of solar panels:

A. Monocrystalline Solar Panels (Mono-SI)

With a conversion rate of up to 23.54%, which makes it the highest performance solar panel on the market nowadays.

Monocrystalline solar panels are made of quality silicone and well known for their efficient usage of space.

Though having a great conversion rate, the production of Monocrystalline panels results in a huge amount of waste contributing to a high cost per unit production.

Key Features

  • Conversion Rate: Up to 23.54%
  • High cost

B. Polycrystalline Solar Panels (p-Si)

Despite polycrystalline solar panels are also made from silicon, they are not as efficient as the monocrystalline ones.

The reason for that is polycrystalline solar panels contain impurities in the crystal, which highly reduces it’s efficiency to around 8%.

However, unlike monocrystalline, the production of polycrystalline panels releases a low amount of waste and consumes less raw materials and energy resulting in a fairly low cost per unit production.

However, in addition to low efficiency, one of the drawbacks of this type is it requires more space compared to the monocrystalline ones.

Key Features

  • Conversion rate: Up to 16.5%
  • Low cost

C. Thin-Film Amorphous Silicon Solar Panels (A-SI)

This type is produced by arranging thin-film solar panels in layers, which allows it to work in even the lowest sunlight conditions.

The downsides of this type are: it occupies a lot of space, and have pretty low performance.

Key Features

  • Conversion rate: Up to 10%
  • Portable and flexible
  • Lightweight
  • Low cost

4. Battery Type

Battery type is a very important factor to consider before buying a solar light.

You need to always opt for higher quality batteries, as they will last longer, have low maintenance, and made of durable materials.

There are many types of solar batteries, however, the most commonly used types in the solar powered lights industry are lithium-ion batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and lead-acid batteries.

Here are the most common types of solar lights’ batteries: 

A. Lithium-ion batteries

They are small, lightweight and most importantly, they have a very low self-discharge percentage. In other words, you can store them for months and they won’t lose their charge.

The average lithium-ion battery has a charge/discharge efficiency of 85% and can last for 500-1000 charge cycles.

Further, they resist the memory effect, which means that they won’t lose their charging ability over time and this is very important, especially for solar lights as in some cloudy days you won’t be able to fully recharge the battery.

The only downside to the Lithium-ion batteries is they tend to be pretty expensive in comparison to the other types. 

Key features

  • 500-1000 charge cycles
  • Can be fully charged in 2-4 hours
  • 10% self discharge a month
  • No maintenance required

B. Nickel-cadmium batteries

The second item in this list is the Nickel-cadmium batteries. Sadly, this type suffers from the memory effect, and this is why they don’t last as long as the Lithium-ion ones.

Don’t get me wrong, nickel-cadmium is still a very good option as they can provide up to 1500 charge cycles before they lose their capacity.

Moreover, they are much cheaper than the lithium-ion batteries and tend to be 2-3 times less expensive making them a great choice for people with limited budgets.

Key features

  • Up to 1500 charge cycles
  • Can be fully charged within an hour
  • 20% self-discharge a month
  • Require maintenance once every 1-2 months

C. Nickel metal hydrid batteries

The nickel-metal hydride battery is another amazing option that can provide 300-500 charge cycles with a charge/discharge efficiency of roughly 75%.

Although this type tends to be heavier and has a high self-discharge ratio, they are quite cheap and can be recycled.

Key features

  • 300-500 charge cycles
  • Can be fully charged in 2-4 hours
  • 30% self-discharge a month
  • Require maintenance once every 2-3 months

5. Battery Capacity

Battery capacity is measured in terms of mAH and as a general rule, the higher mAH your battery has, the longer it will last. However, it will also take longer to get fully charged.

Having a high capacity battery is a must, especially in winters when the days are shorter and .

It’s important to mention that the solar light running time highly depends on the operating voltage.

For example, a branch of string solar lamps with 30 LEDs will drain the battery much faster than a branch with only 10 LEDs

6. Runtime Vs Charge time

This gives you an idea of the solar light efficiency. The best solar lights are the ones that have a high Runtime/Charge time ratio (>1).

In other words, they should have a short charging time compared to the runtime.

For example, the average solar light will fully charge within 6-8 hours and can offer 10-12 hours of light. This means the average solar light will have a Runtime/Charge time ratio of 1.5.

7. Brightness

Brightness is measured in lumens which is the illumination capacity of the bulb.

Solar bulbs are available in various lighting intensities from huge playing fields floodlights to small shade lights. Therefore, you need to know exactly how much lumens you need.  

The number of lumens you need varies depending on:

  1. The area you wish to illuminate
  2. Coverage Distance
  3. How bright you want this area to be (high-intensity light or more vivid and smooth one)

Here is a small cheat sheet for the type of light and the suitable number of lumens:

  • Step lights: 12:100 lumens
  • Wall lights: 50:200 lumens
  • Landscape lights: 50:300 lumens
  • Path lights: 100:250 lumens
  • Pool lights: 200:400 lumens
  • Motion sensor lights: 300:700 lumens
  • Flood lights: 800+ lumens
  • Small garden (50 m^2): 1600 lumens
  • Medium garden (150 m^2): 2800 lumens
  • Street lights: 5000+ lumens

Note: The brightness of the light can vary depending on the amount of sunlight it gets during the day. For example, the solar light will appear to be less bright on gloomy days than it’s on sunny summer days.

8. Durability and Weatherproof

Your solar lights are meant to stay outdoors. Therefore, you need to make sure your solar powered lights are made of high-quality materials in order to withstand the toughest weather conditions.

Choose solar lights that are made of stainless steel, ABS plastic, and cast aluminum.

In addition to the high-quality materials, your solar lights must be water and weatherproof. So it’s important to check the IP rating of each product.

The IP rating or the Ingress Protection rating is an international standard that defines the sealing effectiveness of electrical devices.

Here is a cheat sheet of the most common IP ratings and the water protection they provide:

  • IPX0: No water protection
  • IPX1: Dripping water
  • IPX2: Vertically dripping water
  • IPX3: Sprays up to 60°
  • IPX4: Splashing water (In any direction)
  • IPX5: Water jets
  • IPX6: Powerful water jets
  • IPX7: Up to 3 feet (1 meter) immerse
  • IPX8: Over 3 feet (1 meter) immerse

9.  Lighting Modes 

In case you don’t know what lighting modes are, you can check this quick video to have a better understanding

The best solar lights should have multiple lighting modes, as it allows you to customize the lights to suit your needs.

For example, you can use the dim mode for more calm and soothing lighting and switch to the flash mode for more intense illumination.

Note: Choose solar lights with an automatic on/off function, which allows the lights to turn on and off automatically depending on how dark it is using the sensors as we mentioned before.

10. Colors

Solar lights are available in a wide variety of colors and opting for multi-color solar lights is always a good choice. 

The multi-colored lights are always fun to watch and can be used for different designs to decorate your home.

For example, if you are looking for a dramatic effect, you can go with single-colored strings to illuminate large areas. 

Further, you can also use both white and colored lights to create attractive and complex designs that will catch the eyes.

11. Remote Control

To be honest with you, having a remote control is more of a luxury than it’s a necessity.

Don’t get me wrong, it’s great to have a remote, as it allows you to change: colors, modes, or even turn on/off the lights without leaving your place.

However, you don’t always need it and if you have as many remotes as I do (32 BTW) you can find it really overwhelming.

12. Warranty

Warranty is another very important factor and it’s not recommended to buy a product with no warranty.

Think of this, if the manufacturers themselves don’t trust the product enough to give you at least a 1-year warranty, then why should you trust it?

13. Cost Vs Quality

There is a wide variety of solar lights and the price may vary depending on their features, such as light intensity, materials, runtime Vs charge time, battery capacity, etc.

The best solar lights are not the most expensive ones, in fact, some companies tend to overprice their products to trick the customers into thinking that this product must be perfect.

What we want you to do is to look for the best quality for price product and never exceed your budget.

Last Words

As promised, we provided you with a full definitive guide on how to choose the best solar lights on the market.

In the end, we really hope you enjoyed this article and stay tuned for more awesome solar tips and tricks from Solar Energy Hackers.

Do you find this guide helpful? Do you have any questions or ideas to make this guide even more helpful?

Please, let us know your thoughts in the comment section below.

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