Zebralight H501 Part 2

Egsise · May 8, 2009

Moderation: Comment removed. rule violation.

Pic from http://www.kuvaboxi.fi/julkinen/2b7o2+vesa-lampputesteja-2009.html

wapkil · May 8, 2009

I don't know what happened here but I remember that there used to be a post somewhere informing that the measurements in the picture in the post above represent the difference in lumens output (taken with some sphere?). Do I remember correctly? I tried to look at the site linked in the post but I don't understand a word in any Finno-Ugric language.

Does anyone know how it was measured? In comparison to the ZL specifications these results look surprising...

kwieto · May 9, 2009

It was telling about "Lightbox"

In my opinion, the results posted above are less surprising than Zebralight specification, in fact.

Compare, according to the specifications:

For LOW: H50 = 2.6lm/3,5days | H501 = 3.3lm/3,5days. H501/H50 = 26.9% increase of efficiency.
For MID: H50 = 13lm/19h | H501 = 18lm/19h. H501/H50 = 38,5% increase of efficiency.
For HI: H50 = 66lm/2.3h | H501 = 96lm/2.3h. H501/H50 = 45,5% increase of efficiency.

I really don't belive that light which is 45,5% more efficient in Maximum mode, in minimum mode gets only c.a. a half of that efficiency.
And I still don't belive that they increased the light output that much without shortening battery runtime.
And if they did, the driver efficiency in H50 would be only c.a. 60% or less (??)

The measurements posted above looks more realistic.

LOW: H501/H50 = 16% improvement
MID: H501/H50 = 0% improvement
HI: H501/H50 = 8% improvement

Except this 0% on MID level, looks more "real" than in the specifications from the Zebralight.

Maybe someone could measure and compare the current for both lamps?

I still think that most of the "improvement" in H501 is because of the different optics. If the difference was in the driver, that would mean, that the H50 driver is VERY poor.

vee73 · May 9, 2009

I have measured all of the lamps in this lightbox:
http://www.youtube.com/watch?v=EHeqP3BZSuY

http://www.kuvaboxi.fi/mediaobjects/orig/pub/2009/05/08/8143010478550159287orig.jpg

davidt1 · May 10, 2009

vee73 said:
I have measured all of the lamps in this lightbox:
http://www.youtube.com/watch?v=EHeqP3BZSuY

http://www.kuvaboxi.fi/mediaobjects/orig/pub/2009/05/08/8143010478550159287orig.jpg

Thanks. In the picture the H501 seems brighter in all modes.

kwieto · May 10, 2009

davidt1 said:
Thanks. In the picture the H501 seems brighter in all modes.

But it is normal when you have narrower angle.
The diameter of a circle enlightened by H501 is c.a. half of that given by H50.
If you have more concentrated light, it will look brighter even if it produces the same ammount of light (lumens) in fact.

wapkil · May 10, 2009

kwieto said:
It was telling about "Lightbox"

(...)

I really don't belive that light which is 45,5% more efficient in Maximum mode, in minimum mode gets only c.a. a half of that efficiency.
And I still don't belive that they increased the light output that much without shortening battery runtime.

As we recently saw, such efficiency jumps sometimes happen.

kwieto said:
And if they did, the driver efficiency in H50 would be only c.a. 60% or less (??)

In my previous approximation I estimated it even lower - at the 50% level.

When compared e.g. to the Fenix LD10 specification, the H501 numbers don't seem impossible. I know that Fenix gives LED lumens and ZL quotes OTF. I also expected that the runtime can be a little bit lower and the 96 lumen output may be achievable only on the fresh battery. Still, if the difference between the H501 and the H50 were so low, well within the results of the emitter variation, the specification would be simply false.

wapkil · May 10, 2009

vee73 said:
I have measured all of the lamps in this lightbox:
http://www.youtube.com/watch?v=EHeqP3BZSuY

http://www.kuvaboxi.fi/mediaobjects/orig/pub/2009/05/08/8143010478550159287orig.jpg

Thanks for the measurements. Do you think it may be possible that the measurement results in your lightbox may to some degree depend on the beam angle? Maybe you have measurements for other lights for which we know the lumen output (e.g. measured here)?

vee73 · May 10, 2009

Angle does not much seem to affect the measurement result. Hardly any other measurement results are comparable to my measurements. Because there are so many factors. box size, and how well the surface reflects light.
This link has all my lightbox measured lamps:
http://www.kuvaboxi.fi/julkinen/2b7o2+vesa-lampputesteja-2009.html

I also tested the batteries with the help lightbox:
http://www.kuvaboxi.fi/julkinen/2bkam+vesa-aaa-paristotesti.html

kwieto · May 10, 2009

wapkil said:
As we recently saw, such efficiency jumps sometimes happen.

OK, but it was PRE production model.
I belive that some PRE release can contain bugs, but efficiency of production model on the level of 50%... there are plenty of cheap, more efficient drivers on the market.

And I don't know why, according to the specifications, improvement on LOW would be only 26,9%, when on HI it would be 45,5% (69% better on HI) ?

Usually the more current is given to the driver, the less efficient it is (?)

According to the measurements: I think that if no big mistake was done and the measurements were done in the same conditions, you can use results at least to compare tested devices.
It is no matter if it was 800 lux or 820 or 790. More important is that the difference for HI was 8%, far less than declared by the producer.

wapkil · May 10, 2009

vee73 said:
Angle does not much seem to affect the measurement result. Hardly any other measurement results are comparable to my measurements. Because there are so many factors. box size, and how well the surface reflects light.
This link has all my lightbox measured lamps:
http://www.kuvaboxi.fi/julkinen/2b7o2+vesa-lampputesteja-2009.html

Thanks once again. I asked about other measurements to have an idea how the lux readings in your lightbox roughly relate to the lumen output. When looking at your measurements I noticed that you have them for an LD20 light. In MrGman's measurements L2D (which should have the same output) measured 145 lumens. That's ~12 times less than 1745 (lux) number you got. This 12 divider when applied to your H50 measurements gives ~66.7 lumens - almost exactly 66 lumens from the ZL specification. The numbers don't always much so closely but it seems that this 12 times divider for your measurements should be within around 10% range of the real lumen output. This would mean that the H501 in your measurements gave 70-80 lumens.

Of course this is still only a speculation based on a single measured sample but the conclusions seems to be rather unpleasant for ZebraLight. I hope someone with another sample will be able to take measurements and compare the results.

wapkil · May 10, 2009

kwieto said:
And I don't know why, according to the specifications, improvement on LOW would be only 26,9%, when on HI it would be 45,5% (69% better on HI) ?

Usually the more current is given to the driver, the less efficient it is (?)

I think it's not that simple. IIRC the drivers have their peak efficiency somewhere in the middle of the normal operating range and they are much less efficient for both high and low currents. To get 3.3 OTF lumens from current regulated driver you need less than 20mA. That's quite low and, as far as I know, that's also the level where the LEDs start to be inefficient.

That's one of the reasons I thought the specification may be correct. The numbers were high but didn't seem impossible. It's too bad that the vee73's measurements results seem to disagree with my theory :whistle:

JB5 · May 12, 2009

My dog just ate my H501 headband and the glow headband mount. I emailed Zebralight to see if its possible to get a new one. I hope so cuz i have been using this light so much and now I can't. Just glad he didn't swallow the light as well.

LowBat · May 13, 2009

JB5 said:
My dog just ate my H501 headband and the glow headband mount. I emailed Zebralight to see if its possible to get a new one. I hope so cuz i have been using this light so much and now I can't. Just glad he didn't swallow the light as well.

While it sounds comical like saying my dog ate my homework, I just hope your dog doesn't develop any complications. That's a lot of material to pass through a dog (big or small) and the headband hopefully won't get tangled or snagged before it has a chance to be passed. You are probably already keeping a close eye on your dog in case he starts to look sick. You may also want to call a vet and ask for advise. I hope everything comes out ok... literally.

JB5 · May 13, 2009

LowBat said:
While it sounds comical like saying my dog ate my homework, I just hope your dog doesn't develop any complications. That's a lot of material to pass through a dog (big or small) and the headband hopefully won't get tangled or snagged before it has a chance to be passed. You are probably already keeping a close eye on your dog in case he starts to look sick. You may also want to call a vet and ask for advise. I hope everything comes out ok... literally.

Fortunatly everything came to pass. And I have a new headband in route. This is not the first time he has done something like this. We have been lucky to not have any complications...I think the fact that he is such a large dogs helps in this regard.
thanks for the concern lowbat.

Flying Turtle · May 13, 2009

Good to know the dog is fine, and that replacements are available. Sounds like the light itself could be in danger if left within reach. Now that would be a true torture test. :laughing:

Geoff

jhc37013 · May 13, 2009

I got my first Zebralight today, the 501. I am so impressed by the light weight and how comfortable it is. Thanks to all for all your pics and reviews. This is probably become my favorite all around headlamp.

LowBat · May 14, 2009

jhc37013 said:
I got my first Zebralight today, the 501. I am so impressed by the light weight and how comfortable it is. Thanks to all for all your pics and reviews. This is probably become my favorite all around headlamp.

Welcome to the club. These are really great lights, and I don't even use the headband. My H501 lives on my backpack shoulder strap like an anglehead flashlight. I can tap it on for map reading or leave it running to see the trail. When at camp I either stick a push pin at arms reach up on a tree truck and hang the H501 upside down, or use a small plastic Niteize S-hook and attach the H501 to a tree branch. Either way mounting the Zebralight above your head eliminates any glare and makes for a nice little area light. Small, lightweight, single AA cell, and very versatile, you just can't go wrong with a Zebralight.

davidt1 · May 14, 2009

Suggestions for a better H501

I like my H501, but it could be better. So here are some suggestions for the next version of this light.

1. Put the on/off switch on the tail end. This Tank007 shows a good example.

2. Redesign the clip. It's too bulky the way it is. The clip should be longer and starts at the end of the light so that no part of the light hangs out when it is clipped to a pocket. Notice how I have the clip all the up very close to the top of the light. You don't want the light to get snagged by something and falls out. With the on/off switch on the other end, perhaps the clip can be screwed on top of the LED housing.

Don't just be content with what you have. Make it better every time.

xucchini · May 14, 2009

Ordered an H501 a week or two ago.

Just waiting now... :)

Zebralight H501 Part 2

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