Secret Jardin - TNOLED 2x40W GROW

The TNOLED 2x40W Grow is a set of two 90 cm strips in one fixture, 80 watts of cool white light at 6500 kelvin together, for an area of 90 × 60 cm.

µmol/s/W and µmol/J are the same number

On packaging and data sheets you meet a lamp's efficiency in two notations: 2.7 µmol/J and 2.7 µmol/s/W. They look like two different specifications and they are one.

The arithmetic behind it is short. A watt is by definition a joule per second. Micromoles per second per watt is therefore micromoles per second divided by joules per second, and the seconds cancel. What remains is micromoles per joule. Same quantity, same value, just written out longer.

Why that is worth knowing: anyone comparing two lamps who reads 2.7 µmol/J on one and 2.7 µmol/s/W on the other may easily think something is off, or that one figure is better than the other. It is not. What does deserve attention is an entirely different distinction, namely whether the number describes the complete fixture or a single diode, because in this trade that really does matter.

For this set it is 2.7 µmol/J across the whole thing. The bloom version comes out at 2.4, and that difference is in the spectrum.

Technical Specifications:

• Model: TNO80GR
• Power: 80 W total, 2 × 40 W
• Length per strip: 90 cm
• Colour temperature: 6500 K, cool white
• Efficiency: 2.7 µmol/J, that is 2.7 µmol/s/W
• Lit area: 90 × 60 cm
• Supply voltage: 24 V

Frequently asked questions

Is 2.7 µmol/s/W better or worse than 2.7 µmol/J?
It is the same. A watt is a joule per second, so the seconds cancel out.

What should I watch in that figure instead?
Whether it describes the whole lamp or a single diode. That difference is large and common.

What area is this set meant for?
Roughly 90 × 60 cm during vegetative growth.

Why does the bloom version reach 2.4 and this one 2.7?
The spectrum. The 2x40W Bloom page explains why it measures that way.

Video