DIY COB LED Calculator
- Thread starter bggrass
- Start date
bggrass
Well-Known Member
It's working now.
>>
I think I can definitely make a Cree COB calculator that will take as an input any amperage, instead of dealing with the preset ones. It will take a good amount of time as it will be quite tedious to input all the points for all the different cree cobs and bins that are in the calculator.
>>
I am not sure whether it would be worth it figuring out some crazy formula that will work with any amperage entered.
You could alternatively also feed the program known data that we know or that others have estimated, say, for the CXB3590s like shown here:
For me that would be MORE than sufficient.
Right now the calc doesn't have some important data, like (jn my case) with a 1750mA driver, I am especially interested in the 875mA values since I get 875mA when I connect 2x light fixtures in parallel. And 875mA are also the lowest setting I can dim the driver to. For such LEDs where we have data this could be done with EXTERNAL (CSV) files that have lines with amperage and lumens. The tool could then read in those data from those files. Then your tool wouldn't need to bother about calculating the values. And people could calculate them (or measure them) and then make those external files for each type of LED. You also wouldn't need to re-code the tool every time there are new LEDs, simply use such external files with the data? Just my $0.02
** If the values are not linear anyway (which I assume), there won't be a "one-fits all" formula anyway
I think I can definitely make a Cree COB calculator that will take as an input any amperage, instead of dealing with the preset ones. It will take a good amount of time as it will be quite tedious to input all the points for all the different cree cobs and bins that are in the calculator.
>>
I am not sure whether it would be worth it figuring out some crazy formula that will work with any amperage entered.
You could alternatively also feed the program known data that we know or that others have estimated, say, for the CXB3590s like shown here:
For me that would be MORE than sufficient.
Right now the calc doesn't have some important data, like (jn my case) with a 1750mA driver, I am especially interested in the 875mA values since I get 875mA when I connect 2x light fixtures in parallel. And 875mA are also the lowest setting I can dim the driver to. For such LEDs where we have data this could be done with EXTERNAL (CSV) files that have lines with amperage and lumens. The tool could then read in those data from those files. Then your tool wouldn't need to bother about calculating the values. And people could calculate them (or measure them) and then make those external files for each type of LED. You also wouldn't need to re-code the tool every time there are new LEDs, simply use such external files with the data? Just my $0.02
** If the values are not linear anyway (which I assume), there won't be a "one-fits all" formula anyway
bggrass
Well-Known Member
There is no one fits all formula. I hear you on the .875A, but you don't have that value on the spreadsheet you posted. I can add a calculation for all of the above crees at .875A if you know what numbers to use at that amperage for lm/w, voltage and efficiency.
As of the rest of your ideas, they are good, but tedious is right, and I only have so much time...
As of the rest of your ideas, they are good, but tedious is right, and I only have so much time...
sanjuan
Well-Known Member
Edit: the working link is in bggrass' sig: https://www.dropbox.com/s/csny22u6yrpptaj/DIYCOBLEDCalculator.jar?dl=0.
coreywebster
Well-Known Member
Hey all
I have downloaded the dropbox link and downloaded the latest java but for the life of me can't get it to open with java. It doesn't give me the option even if I select choose a program from list ect. There doesn't seem to be a way to get it to open it. I have tried navigating to where java is installed and tried a few of the icons but none seem to open it. What am I missing?
If anyone can suggest where I'm going wrong. I'm running windows 10
If I navigate to the java folder I have a folder labelled jre.1.8.0_91 within that I have a bin folder and lib folder from there I'm a bit lost.
Would appreciate someone pointing out the my obvious error.
Cheers
C.W
I have downloaded the dropbox link and downloaded the latest java but for the life of me can't get it to open with java. It doesn't give me the option even if I select choose a program from list ect. There doesn't seem to be a way to get it to open it. I have tried navigating to where java is installed and tried a few of the icons but none seem to open it. What am I missing?
If anyone can suggest where I'm going wrong. I'm running windows 10
If I navigate to the java folder I have a folder labelled jre.1.8.0_91 within that I have a bin folder and lib folder from there I'm a bit lost.
Would appreciate someone pointing out the my obvious error.
Cheers
C.W
bggrass
Well-Known Member
Download the file and double click it. It should run. If it doesn't, go to oracle's website and install java for consumers on your pc and then double click on the file again.
http://www.java.com/en/download/
http://www.java.com/en/download/
coreywebster
Well-Known Member
Cheers. Yeah I have done both those things. I have no idea why it wouldnt open. Should it open with a browser with java running on that browser. I have been trying to open directly with java.
I will keep trying with it.
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coreywebster
Well-Known Member
Thanks for responding. I literally just figured it out.
I have WinRAR installed so the download showed as a WinRAR icon, I automatically assumed I had to extract the files and run the program within. But clearly it didn't need extracting just running with java. I have just this second opened it correctly.
I appreciate you trying to help. Even More so for putting this little tool together in the first place.
Bravo old bean Bravo.
coreywebster
Well-Known Member
bggrass
Well-Known Member
I have no idea. I just added them because someone asked. The numbers are from this table:
http://rollitup.org/t/cob-efficiency-spreadsheets.865238/page-21#post-12686218
ruwtz
Well-Known Member
Props to @bggrass & co for doing this - great work. I've been getting into cob research this past couple of days for the first time and you've given me a start with some solid numbers that I can use in costing/efficiency analysis, which I have to do to convince myself to spend the cash.
If you don't mind I'd like to share what I got out of this:
For a 3.5x7ft flood table veg room only (total 24sqft) assuming no other source as i'm ditching these MarsII panels.
Speccing out CXB3590 36v 5000k + 4.6 profile heatsink
8 of these at 700ma gives me 262vf, 305w at the wall, 122par/watts, a ppfd of 244 and 74% cob efficiency.
Now obviously you amazing people have made sure the calculator is correct, so does this sound like a good setup for my veg table? I was thinking a 6ft bar with 2 rows of 4 so each cob covers 3sqft and dimmable so I can max out 244ppfd by the end of veg.
Do you think this is enough???
If you don't mind I'd like to share what I got out of this:
For a 3.5x7ft flood table veg room only (total 24sqft) assuming no other source as i'm ditching these MarsII panels.
Speccing out CXB3590 36v 5000k + 4.6 profile heatsink
8 of these at 700ma gives me 262vf, 305w at the wall, 122par/watts, a ppfd of 244 and 74% cob efficiency.
Now obviously you amazing people have made sure the calculator is correct, so does this sound like a good setup for my veg table? I was thinking a 6ft bar with 2 rows of 4 so each cob covers 3sqft and dimmable so I can max out 244ppfd by the end of veg.
Do you think this is enough???
klx
Well-Known Member
Wall watts is less - 8 of these at 700ma gives me 262vf, 194w at the wall, 122par/watts, a ppfd of 244 and 74% cob efficiency. In reality it will be probably about 8% more.
Personally I would get bigger drivers (1400mA) so you have the option of more grunt, then dim them if you want to but if you are SURE you will not need more then it is nice to be able to fit 8 cobs on the one driver.
How much is electricity where you are? If its cheap you could use less cobs at higher current easily for veg. If its expensive then 74% is pretty sweet.
Personally I would get bigger drivers (1400mA) so you have the option of more grunt, then dim them if you want to but if you are SURE you will not need more then it is nice to be able to fit 8 cobs on the one driver.
How much is electricity where you are? If its cheap you could use less cobs at higher current easily for veg. If its expensive then 74% is pretty sweet.
ruwtz
Well-Known Member
Interesting. I just ran it again and i'm still seeing 305w at the wall.
But yes agreed 1.4a is going to suit me better and can be dimmable. I'm chatting to Dan at Timber and i'll probably be happy to take a couple of their 200w kits, but I would like to get this watts calculation right before I do!
ruwtz
Well-Known Member
Ah ok, nice one! This improves things a lot!
I misread that box as the desired target efficiency of the system. I didn't realize driver efficiency could be so variable. Noob.
Ok I think I'm ready to step into this and go with cob. It's far too exciting in the proof to ignore. Thanks everyone for your help.
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coreywebster
Well-Known Member
ruwtz
Well-Known Member
Ordered two of the 200w kits from Timber Grow together with a pair of bar mounts. Spec'd out the 5000k DB bins for veg only.
I know I could have built this for myself but time is limited now and in any case Timber are very competitive for the work put in. Very good price I feel for basically plug & play. Dan over there has been excellent and speedy, and i'd recommend anyone to talk to him if you're considering cob for the first time like me.
I know I could have built this for myself but time is limited now and in any case Timber are very competitive for the work put in. Very good price I feel for basically plug & play. Dan over there has been excellent and speedy, and i'd recommend anyone to talk to him if you're considering cob for the first time like me.
