the brightness of a lightbulb is something we have quite a lot of control over now, we can make bulbs to fill a number of brightness desires. However, there are limitations. Even with highly efficient bulbs, or LEDs, being even more efficient, you need electricity to light them, and brighter lights inherently need more electricity, if they’re not significantly more efficient than the dimmer alternative.
lighting fixtures in houses have very little problem with this, capable of tapping into the massive amount of power available through the mains supply, they can in theory use as much as they want. So we then design them to fill the desired brightness we have.
Flashlights/torches, on the other hand, have to deal with power supply limitations, and people expect them to last quite a while, which puts a ceiling on how much power they can consume. If you want to design a flashlight to last, say at minimum 3 hours, then you would take the amount of power your batteries can store, divide that into 3 hours, and that’s how much power you can use per unit of time. This puts a limit on the power your bulb can use, which limits the brightness it can achieve.
as a quick example, lets use some made up numbers and an oversimplified idea of the maths, but say you have a battery that holds 10 units of electricity, and it takes 1 unit to make a small amount of light for 1 hour. you can have a flashlight that makes a small amount of light for 10 hours, or twice as much light for 5, but you can already see that improving the light drastically shortens the lifespan of that battery. to make 3 times as much light, you’re already down to about 3 hours
on the other hand, the light in your house can easily spend 10 units an hour to make quite an extravagant amount of light without issue, because in the grand scheme, 10 units isnt much electricity for the mains to supply.
theyre not.
but for those that are, flashlights are designed to use less power because they have their power source with them. and long-lasting lightweight power is valued over maximizing brightness.
new technology has changed this a bit. more lumens (brightness) per watt (power) with newer technology.
my nightcore headlamp is rated at 190 lumens for 17hr (more like 2-3 hr sadly) on 1800mah*3.7v? = 6watt-hours. your average household bulb is 1000-1600lumens and you can expect 70-100lumens/watt from LEDs. so figure 10-15watts to run such a bulb.
you can get a flashlight that will pump out 1000 lumens or more. it just will need a 10-20wh battery to run for an hour.
https://www.nitecorestore.com/Nitecore-NU32-Headlamp-p/fl-nite-nu32-bk.htm
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