- 50%

http://www.light-reviews.com/fenix_p3d_ce_q5/

When im looking at the figures in this review for battery life, and they say something like 5 hours to 50%, what exactly are they refering too? 5 hours until the batteries are half used? 5 hours till the brightness is half of that mode? 5 hours till the battery indicator comes on, and then you can choose a lower level? I mean if i see 5 hours, does that mean after the 5 hours of that mode, that i can put it on a lower mode, and have hours more light using the other half of the battery power?

I find this a little confusing. I am trying to figure this all out and remember it, so i know if i put new batteries in, it will last THIS long, or it will last THIS long, and then i have to turn the power down, onto THAT mode, and it will last quite a while more.

Anyone help me with this lieelt dilemma?

light output from 100% down to 50%
on high its gonna eat up your battery voltage and the light level will drop faster :thumbsup:

The 50% measurement isn't the best way to measure runtime, a graph is much better.
Some lights are 2 hours to 50% then another 5 mins until nearly 0%. Others hit 50% quicker and steadily continue to dim like direct driven lights.

TONY M said:

The 50% measurement isn't the best way to measure runtime, a graph is much better.
Some lights are 2 hours to 50% then another 5 mins until nearly 0%. Others hit 50% quicker and steadily continue to dim like direct driven lights.

Click to expand...

This is all because the power is regulated, right?

torpeau said:

This is all because the power is regulated, right?

Click to expand...

Righto...years ago on CPF there was a debate about the best way to measure run time...the vote was that would be 1/2 100%.

That standard stuck and remains I believe the best way to measure...but it`s true...does not always tell the rest of the story. Just the brighter half...many folks don`t care that much about the tail. At 1/2 they are changing/charging the batt...me too.

I dont like non regulated lights. If i buy a mag, and the lumens drop off and drop off and drop off, then whats the point in quoting lumens at all? its worthless. I love regulation, becuase you get what you pay for.

I looked at the graphs (which i forgot to do) and it all makes much more sense now. Also with me using AW RCR the drop off is very quick, compared to primaries.

techwg said:

I dont like non regulated lights. If i buy a mag, and the lumens drop off and drop off and drop off, then whats the point in quoting lumens at all? its worthless. I love regulation, becuase you get what you pay for.

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Before CPF, I thought those (non-regulated) LED lights I bought from catalogs were cool because I didn't know any better. Now I give them away or leave them somewhere in public so someone else can use them.

yea, to me its a big con. Just because a light has 60 lumens for the first 5 mins before going down in steady steps, should not give you the right to market a light as 60 lumens. At least tell people "60 lumens for about the first 10 mins, then it spirals down and down from then for the next 1 hour and then is dead."

I bet they would not sell as many, but then they have to sell them. If i want 60 lumens, god damn it i need 60 lumens, not 45. If i want low power i will CHOOSE to set my light to low power or use a low power light. I can guarentee that my LED lights are pretty much constent, and fluctuate only minimally, and stay in the same area. I just hate non regulated lights, hate them with a cap F. Maybe you can tell

Problem is that without seeing a graph, you cannot know how good the regulator is. These are many cheap lights advertised as regulated, but with a lame slope in their graph.

IIRC, 50% is used because that is where the decrease is brightness first becomes visually noticeable. Because of the logrhythmic way our eyes perceive light we do not readily notice a gradual 20% or 30% decrease vs a 20 or 30% jump. I could be wrong but remember reading that somewhere.