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What Affect the Brightness of A Flashlight?

Nov. 26, 2021

Although lumens directly affect the brightness of a flashlight, this measurement does not fully affect the brightness of the flashlight. Other factors including battery and bulb type may have an impact. FULANG, the manufacturer of powerful flashlights, explains.


The flashlight's run time determines how long it takes for the light output to decrease to 10% of the new battery rating. It is measured in hours. You may notice that the light output may drop slowly or remain constant over time and then drop suddenly. Some models have various light modes, which means the runtime is related to the light mode.

Note that high lumen lights have reduced run times compared to low lumen lights. 

Rechargeable 18650 Flashlight

Rechargeable 18650 Flashlight

Color Rendering Index

The CRI or color rendering index affects the brightness of a flashlight. Cheaper lights have a high color temperature and a very blue tint. However, you will find that some high-end LED flashlights have a lower color temperature and produce an attractive bright "white" light. Flashlights with a CRI of 80-90 are very similar to sunlight. That's why you need to find a device that balances light quality and lumens.

Beam Distance

Beam distance is the distance a flashlight can emit useful light. It is measured in meters. The distance varies with the brightness setting you choose. When evaluating beam distance, you will find that some flashlights provide a wide area of illumination, while others give off small, targeted illumination. Floodlight flashlights are best for close activation, while long range flashlights help illuminate distant objects. 


Adjusting Output

Beware of flashlights that do not have circuit boards or resistors.  These are direct drive flashlights that push all the battery power directly to the LED in an attempt to have the highest lumen levels. They are also the least reliable and least durable.FULANG's flashlights have PC boards and resistors to control the power of the LED, which will allow your flashlight to live a long and happy life. 

Battery Type

The type of battery affects the brightness of the flashlight. Models with disposable batteries are usually less bright, but compact in size. You can find flashlights with common battery sizes such as AA or AAA. 

The best option is to find a high-quality flashlight that has replaceable, rechargeable batteries. The best ones can even be turned off in an emergency with lithium-ion batteries or typical alkaline batteries.

Lamp Type

LED technology is the most advanced technology available today and you can find it in most of the bulbs on the market. However, some of the newer flashlight models now come with krypton or incandescent bulbs. Considering the impact resistance, energy efficiency, run time and brightness options of LED bulbs, they are hard to beat. Incandescent bulbs always last shorter and use more energy.

The color temperature of LEDs differs from various flashlights, which may affect brightness. 

Brightness Levels

Some flashlights have two brightness levels - low and high. However, these devices will only give you a longer battery life at lower settings. There are other flashlights with up to ten brightness levels, some of which allow continuous variation. All of these affect the brightness and runtime of the flashlight. 


What Affect the Brightness of A Flashlight?cid=4

When looking for a bright flashlight, be sure to check other factors, as all of them can affect the brightness of the flashlight as well. If you want longevity, durability and quality, stick with FULANG, a well-known brand that develops and designs its own flashlights and keeps them honest. Get a quote now by sending us an email message.

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