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LED homebuilt light/Seneye readings

tubamanandy

Member
Joined
28 Feb 2013
Messages
362
Location
Thornton, Lancashire
Just built a new dimmable light unit based on 24 x Cree XP-G2 leds for my 90 ltr fully planted aquarium with CO2/EI ferts etc

Just taken my first light readings at the base with my Seneye - not sure how accurate they are.

Would someone be so kind as to interpret the results ? I'm guessing I have quite high light and may need to dim the unit down a bit. Would you agree ?

PAR=329
LUX=12160
K=4275 deg

Readings taken at base of tank
 
What unit does it use for PAR? if its micromoles (um) then that is Klingon levels of lighting I believe high to very high is around 100um at the substrate
 
Any pics please?
 
AKQA2wC
AKQA2wC
 
25 Cree XP-G2 @ about 300lm per LED gives 7200lm !! (Also 24 x 5 Watts -> 120Watts).

Converting to T5 equivalent to roughly work out Watts/gallon (US).

Assuming smallest T5 tube (22" @ 24W) gives only 1000lm.

So your LED's are equivalent to 7 off 22" T5 tubes (that's 168 Watts over 90l !!!, 23US gal -> an absolute monsterous 7watts/ USgallon, beyond the end of high tech @ 5W/USgal !!).

I do hope you are running at less than 100% light output !!
 
25 Cree XP-G2 @ about 300lm per LED gives 7200lm !! (Also 24 x 5 Watts -> 120Watts).

Converting to T5 equivalent to roughly work out Watts/gallon (US).

Assuming smallest T5 tube (22" @ 24W) gives only 1000lm.

So your LED's are equivalent to 7 off 22" T5 tubes (that's 168 Watts over 90l !!!, 23US gal -> an absolute monsterous 7watts/ USgallon, beyond the end of high tech @ 5W/USgal !!).

I do hope you are running at less than 100% light output !!

Ian do you base the conversion on a small t5 to do the calculation when converting led output to watts per gallon?? Or is this just a guesstimate.
Im running 4 tmc 1500nds over 1300 litre so do I convert using the small t5 tube as a base????
 
UPDATE: Taken some more figures with a power meter and the Seneye:-

NOT including the silent 2 x 140mm fans:-

Unit on 100% power actually draws 115W and 0.73A
Running at 50%, lighting at base around PAR=60, LUX=2225, K=4200

From a viewing point of view, I'd like to run the unit at 75% which probably gives me PAR values at base of around 60-100 and should be able to grow most plants. I guess running at 50% would still be ok but I like a bright tank.
 
Also mildly interesting to know that the lighting hood (which is basically just a large lump of aluminium heatsink) runs at about 57C with lights on full and no fans. As soon as you turn on the 2 x silent 140mm fans, the unit drops to around 32C. My LED supplier says the unit ideally needs to run under 50C - mine is now well within spec.
 
Ian do you base the conversion on a small t5 to do the calculation when converting led output to watts per gallon?? Or is this just a guesstimate.
I based my T5 lumen output from here. Plant Pro Fluorescent Lamp - T5 / Compact

I think the original research on Watts/USgallon was based on T5 tubes, so need to convert LED lumens to T5 lumens and T5 watts. It is not an exact science, but just to get a guide idea if your tank is low tech, medium tech or high tech, so you know what to do (especially if it all goes wrong) and what to expect.

Reading these forums, too much light over too little water and too little CO2 is probably responsible for 99.9999% of all the issues people encounter in planted tanks.
 
I based my T5 lumen output from here. Plant Pro Fluorescent Lamp - T5 / Compact

I think the original research on Watts/USgallon was based on T5 tubes, so need to convert LED lumens to T5 lumens and T5 watts. It is not an exact science, but just to get a guide idea if your tank is low tech, medium tech or high tech, so you know what to do (especially if it all goes wrong) and what to expect.

Reading these forums, too much light over too little water and too little CO2 is probably responsible for 99.9999% of all the issues people encounter in planted tanks.

Sorry what I meant was that you took the 24 watt tube as comparison. Is that purely because of tank size the original poster has
 
Sorry what I meant was that you took the 24 watt tube as comparison. Is that purely because of tank size the original poster has
Just guessing that at 90litre the next sized tube up (39Watt) @ 890mm long would be too big. The exact tube size doesn't matter, I was just getting a rough LED lumen to T5 Watts conversion.
 
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