Runtime graphs from my new lightbox setup

hiuintahs

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I just picked up a new data logging light meter and I have been fascinated with Quickbeam's and Selfbuilt's tests and their ability to test output over time..........so I finally made the plunge. I give them credit for steering me into the milk carton light box setup and graphing the data in Excel.

I tested some of the lights I have and it was fun to see which lights have the most linear output along with efficient drivers. This helps me decide which ones are keepers and which ones I give away or sell.

As for the milk carton lightbox.......I cut off the top and made a lid which I then glued a white piece of poster board to the inside. That way I could get into the box if I needed. I also made the main hole equivalent to the diameter of my biggest light........a Mag D. Then I cut out little white card stock covers with holes to match the various lights I have. That way I could keep all the light in the box and make the test very repeatable.



Also I made a 9v linear power supply to power the meter so I didn't have to worry about going through batteries for the many long runs. These are the Lights that I tested. I'm mostly an AA and AAA Eneloop guy. All lights were tested with freshly charged Eneloops.

Romisen RC-N3 II, XP-G R4
Olight T25T, XP-G R5
iTP SA2, XP-G R5
Streamlight 4AA PP
MiniMag Terralux driver w/ SSC P4
Romisen RC-G2 II, XP-G R4
Zebralight H501
iTP A3 EOS, Q5

I still need to test my Streamlight Microstream and PT EOS P4 modified headlamp. I'll update later. As far as the numbers on the left of the graph, that is the Lux reading from the meter. Not sure how to equate that into lumens. I just use it as a relative comparison.





I found the Olight T25T and iTP SA2 to be the most efficient and linear lights I have. Underneath the graphs I did some calculations to figure out which lights preformed the best. In addition to LED color tint and beam pattern, I've always been interested in the lights that can hold constant output til the batteries are almost used up. I love seeing those straight lines. Basically, efficiency in brightness over the run is the area under the curve. A light that is half as bright should last twice as long right?

Remember when the Streamlight 4AA Propolymer was such a popular light? That was my first LED light. Now that light is near the bottom in performance especially considering the fact that it has 4 batteries. Also of note is the Romisen RC-N3 II, two mode light. The lower setting isn't very efficient at all. And so it makes no sense to even have that function in my opinion. In Low mode, if the brightness was going to be half of HI mode, then I would expect the run time to be at least twice as long as it was on HI. I love the price and the R4 tint though.

It's these characteristics that you'd never Know existed unless you tested against other similar lights.
 

Robin24k

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Nice setup! Just wondering...how did you convert data from the light meter into Excel-friendly format? The text file output is one heck of a pain to process, so I ended up writing a small program to clean up the data for me (remove everything except lux, and convert something like 1.05K to 1050).
 

hiuintahs

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Joined
Sep 12, 2006
Messages
1,840
Location
Utah
Nice setup! Just wondering...how did you convert data from the light meter into Excel-friendly format? The text file output is one heck of a pain to process, so I ended up writing a small program to clean up the data for me (remove everything except lux, and convert something like 1.05K to 1050).

It took me a little research on how to do it because I don't use Excel all the time but this is what I did. This might be what you did too.

I started Excel, then did File - Open and then selected the .txt file. I went with the defaults for bringing it in except one thing. Instead of hitting "finish", I'd hit "next" and I'd move the line over to allow a space in front of the column. I know this doesn't make sense without showing but I could PM you or email you more explicit instructions. I was having the most significant digit dropped from the numbers that were less than 1.00k such as whole numbers like 970 would come in as 70. I have no idea why but that was the fix.

Once all the data from the meter was in a column, I created another column with this equation LEFT(A1,4)*1000. 4 for a number such as 4.29k or 5 for numbers like 11.29k. And then copy that equation all the way to the bottom. That gets the 'K' off of the number (only takes first 4 positions from the left). At the same time I multiply it into a whole number. So now I have a column that looks right but has a built in equation. I then do a copy of this whole column and instead of just pasting it, I do a Edit - Past Special and choose "Values" only. Then I end up with just a column of numbers without any letters or equations.

Hope this helps.
 

Robin24k

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Sep 8, 2009
Messages
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Looks like I didn't miss any option in the HD450 program then. :) Actually, there's no 64-bit driver for it, so I have to use a 32-bit VM to download the data. :crazy: I'm looking forward to the SDL400...the HD450 goes through 9V batteries fairly quickly, and I don't have many of them...

The program I wrote does everything, but it's rather crude. If you want a copy, feel free to PM me. It takes the text file as input and saves a new text file with only numbers, which you can just copy/paste to Excel. Saved me a lot of time and eye strain. :D
 
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