DIY COB LED Calculator

guod

guod

Well-Known Member
tomate said:
Now when I hit the Calculate button, I get an error telling me I have to enter numbers in the input text fields.
But all the input fields are filled.
Click to expand...
maybe the problem...
Java uses point instead of comma for fractions
0.7 instead of 0,7
 
coreywebster

coreywebster

Well-Known Member
oh dear, where did all my lovely efficiency go to.. If these calculations are correct I have just lost 8-10%. I thought they were more efficient than Cree. Down to 42% @ 1400mA, seems that's the difference between 90cri and 80 cri. The 90s are 42.39%
Sheeeet
 
bggrass

bggrass

Well-Known Member
guod said:
maybe the problem...
Java uses point instead of comma for fractions
0.7 instead of 0,7
Click to expand...
I just looked at the error he gets, it's definitely an outdated java version.

There is no decimal point when you enter amps. It takes the value in miliamps mA.
 
tomate

tomate

Well-Known Member
Still no luck. Updated to jre 8 update 102. Used always points for fractions.
The old calculator is still working.

citicalc.jpg
 
bggrass

bggrass

Well-Known Member
coreywebster said:
oh dear, where did all my lovely efficiency go to.. If these calculations are correct I have just lost 8-10%. I thought they were more efficient than Cree. Down to 42% @ 1400mA, seems that's the difference between 90cri and 80 cri. The 90s are 42.39%
Sheeeet
Click to expand...
I would take the cree estimates with a grain of salt. When I tried to pull out the formulas for cree, on their cree pct tool, the lumens that I got were about 20 lumens per watt lower. Check it out for yourself for the cree cob you are looking at and you'll see that the lm/w on the efficiency spreadsheets and the ones on the website are different. I'm not sure how Supra pulled those numbers back then or what he accounted for... Just by looking at the difference, cree and citizen are probably very close in efficiency. We are using different data when comparing...
 
bggrass

bggrass

Well-Known Member
Look at the lumens per watt of the cobs you are comparing on the cree tool and the citizen at the same Tj and amperage. If the lumens per watt are close on both, then they are supposedly equivalent... supposedly

If we run them through the same formulas they should output an equivalent result.
 
muleface

muleface

Well-Known Member
Im still not getting how to calculate efficiency. if I wanted to run 12 cxb3590's would something like a HLG-240h-c1750A be my best bet? I am thinking it would take 3 of them but they would be pretty much at their volts limit, if not slightly over. 143v.
 
muleface

muleface

Well-Known Member
captainmorgan said:
53% efficient, 4 COBs per driver at 142 v with HLG240H-C1750
Click to expand...
how did you get that number? also, do you have any suggestions for running 12 of these COBs? a different driver or is the one I am talking about a good choice? thanks for your quick response.
 
linky

linky

Well-Known Member
The Enter drive efficiency in % for total wattage field, what is that exactly and what is the answer for 3590's 3500k CD bin 36v?
 
ruwtz

ruwtz

Well-Known Member
linky said:
The Enter drive efficiency in % for total wattage field, what is that exactly and what is the answer for 3590's 3500k CD bin 36v?
Click to expand...
Driver efficiency rating, specific to your chosen driver.

Meanwells are something like 94 or 96% efficient, can't remember which.

This caught me out too.
 
bggrass

bggrass

Well-Known Member
mr. Amsterdam said:
Yes i also need help, i have this same problem with Java 102 update.
Click to expand...
Sorry I don't have a solution. Seems to be some single cases and it seems to happen to users outside US. It's beyond my knowledge. Someone posted earlier that they had to change their settings and language on their OS. I'm not sure how that gets connected. Try running it on your phone...

I thought you were wondering what number to put in the Tj field. For the most part, people around here use 50, as in 50*C.
 
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