XSeries-forum

I gather the 25W is a bit of "Marketing" speak. They are apparently 12.5W each. I was thinking I should change the yellow bulbs in my Angel Eyes, but undecided which kit to get 

[quote="X5LeMans"]
I gather the 25W is a bit of "Marketing" speak. They are apparently 12.5W each. I was thinking I should change the yellow bulbs in my Angel Eyes, but undecided which kit to get 
[/quote]

Tbh probably just go with whatever is cost effective as they are pretty much all of a similar brightness.

[quote="X5LeMans"]
I gather the 25W is a bit of "Marketing" speak. They are apparently 12.5W each. I was thinking I should change the yellow bulbs in my Angel Eyes, but undecided which kit to get 
[/quote]

Some sellers claim that there 25w's are 12.5w per unit, where as others, claim theirs are 25w per unit. I only paid £40 for these, but most sellers are selling these £60'ish.

Big question is are you impressed by them, even if they are 12.5watt each side  that's still 25% more power (and hopefully more brightness) than a 10w led kit And probably a fair bit nicer looking than the standard yellow look!.

Time for a bit of maths & physics....no I won't I'll just tell you the answer.

To double the number of lumens of a light source you need to quadruple the output level of that source.  That does not mean adding more lamps because they are the same 'apparent brightness' it means quadrupling each source.

Think about a 40W std lightbulb and then a 100W bulb...more than twice the power, but not double the light output.  Doubling the light power actually gives you the square root of 2 in terms of an increase, 1.414 times.  To double it you need the square root of 4 - hence 4 times the light power needed.  Sorry, that was a maths bit.. :-[

Richard

Richard..

Yeah.. That's like audio systems then, it generally takes a 10x increase in watts, to double the loudness (all things being equal.. which with audio it usually isn't.

I'm guessing the formula behind audio loudness isn't a gazillion miles away from the same as light lumens V watts, when comparing comparable technologies.

IE cant compare incandescent with LED directly, and then I guess the colour temperature also affects the perceived brightness as well.

Graham

They look the same as my 5W hids4u.

Nice one Richard...... :blink: