ViparSpectra KS3000 Review

The ViparSpectra KS3000 is a great new 300-watt LED Bar light for 3’ x 3’ coverage. It is part of the new KS series of LED Bar fixtures from ViparSpectra. The KS series features top end components with Samsung LM301h and Osram 660nm diodes. They are designed for uniform coverage with larger frames and algorithmically distributed diodes.

A few weeks ago, I tested the ViparSpectra KS5000. It tied the record for photon efficiency among production model grow lights in my testing and produced exceptional density maps in a 4’ x 4’ area. As a result, my expectations for the KS3000 were high. However, it still exceeded them. The KS3000 broke the record for photon efficiency. The distribution of the diodes removes the hot spot and creates incredible uniformity. I give the light distribution an A+. As you will see, its performance in my tests was remarkable.

The ViparSpectra KS series is available on Amazon (US) and Amazon (Canada). In both places, you can use discount code: DrMJCoco.

The ViparSpectra KS series feature the state-of-the-art Samsung LM301h diodes. They also incorporate the leading Osram 660nm diodes to create an ideal spectrum for vegetative and flowering growth. The KS3000 has 4 LED bars. Each bar has 210 diodes. In total, there are 840 diodes or 2.8 diodes per watt. There are 816 Samsung LM301h diodes. 528 of them have a color temperature of 3000k. The remaining 288 have a color temperature of 5000k. There are also 24 of the Osram 660nm diodes.

The diodes on the KS3000 are driven by Lifud drivers with dimming knobs. ViparSpectra and the published stats describe the Lifud drivers as high-efficiency and high-quality. The Lifud driver performed well in my test, but this is my first experience with the brand.

The KS series is designed for uniform coverage. The frames are large, the gap between the bars is larger in the middle, and the diodes are algorithmically distributed toward the ends of each bar. These features combine to eliminate the hotspot and create a uniform distribution of PPFD across the canopy.

The ViparSpectra KS3000 can be run quite close to the canopy. In a 3’ x 3’ area, I got the maximum PPFD up to 1000 µmol/m² at a hanging height of only 21.5cm (8.5in). The low hanging height is very efficient because it ensures that virtually all of the light produced by the fixture reaches the canopy. However, many fixtures that run this close leave the edges and corners underlit. That is not the case with the KS3000. Indeed, the highest PPFD values in the map are along the top and bottom edge. The lowest PPFD was excellent at 661 µmol/m², and it wasn’t even in the corner.

I ran an ePAR test at the same height. ePAR includes light from 400-750 nanometers. It includes all of the PAR light (400-700nm) plus the far-red light (700-750nm). Until recently, only PAR light was thought to power photosynthesis. However, the latest research with lasers and advanced LEDs has demonstrated that far-red light also drives photosynthesis when combined with shorter wavelength light. ePAR measures all of the light that we now know powers photosynthesis.

The ViparSpectra KS series does not have any diodes dedicated to far-red light. However, the Samsung LM301h diodes put out a small portion of their energy in those wavelengths. In my tests, the ePAR densities are about 5% higher than the PAR densities across the map.

The performance statistics from both the PAR and ePAR tests at 21.5cm (8.5in) are impressive! In the PAR range, the average PPFD was 858.7 µmol/m². The average density goes up to 902.6 µmol/m² in the ePAR range. The KS3000 delivered 695.5 µmol of Usable PAR light and 731.1 µmol of usable ePAR light to the canopy. I measured a power draw of 298 watts. That means the ViparSpectra KS3000 sets a new record for photon efficiency in my testing. The Usable PAR photon efficiency was 2.33 µmol/w and Usable ePAR photon efficiency sets a new record at 2.45 µmol/w!

There is a lot to like in these test results. The KS3000 is incredibly efficient. It delivers densities at or above 900 µmol/m² across most of the canopy. The corner and edge values are all high. In the ePAR map, the entire canopy is in the maximum production zone. Growers, with low ceilings will appreciate the low clearance. However, growers with rapidly growing plants may have a hard time running it at only 8.5 inches above the canopy.

I ran a second set of tests at a slightly higher hanging height, 30.5cm (12in). At this height, plants would have almost 4” to grow before the light had to be raised. Growers often think they need to dial in the hanging height exactly but running a little above the minimum hanging height has real performance advantages. In a reflective space, from a higher height, almost the same amount of light will reach the canopy, and the distribution will be improved.

At the 30.5cm (12in) height, the maximum PPFD in the PAR range was 904 µmol/m², which is 96 points lower than the first test. However, the lowest PPFD was 694 µmol/m², which is 33 points higher than the first test. At the higher height the ePAR values range from 740-945 µmol/m². This is an incredibly tight range of density values.

In the 30.5cm (12in) test, the average PPFD was 821.6 µmol/m². In the ePAR range the average density was 860.1 µmol/m². The KS3000 delivered 665.5 µmol of Usable PAR light and 696.7 µmol of ePAR light to the canopy. These values are over 95% of the light that I measured at the lower hanging height. In other words, raising the fixture cost less than 5% of the usable light. The lower Usable PPF and ePPF lead to slightly lower photon efficiencies. At the higher height, the Usable PAR photon efficiency was 2.23 µmol/w and the Usable ePAR photon efficiency was 2.34 µmol/m².

I ran a dimming test with the KS3000 at the higher height (30.5cm – 12in). The dimmer locks into position at 100%, 75%, 50%, or 25%. It is very accurate. At each position, the PAR and ePAR percentages match the dimmer setting. At this height, the densities are perfect to start sprouts at 25%, grow Seedlings under 50%, early veg will do well at 75%, and run 100% from late veg through flowering.

The ambient temperature during the tests was 24C (75.2F). After the tests, I measured the surface temperatures on the ViparSpectra KS3000. The LED bars it a maximum temperature of 40.2C (104.4F). The Lifud driver was even cooler at only 39.8C (103.6F).

In the last several months, I have tested several fixtures that are designed for 3’ x 3’ coverage. The KS3000 easily has the best performance. It puts out the most light, with the best PAR map, and the highest photon efficiency. Some of the other models have lower prices, but with our discount code, the KS3000 comes to less than $0.50/µmol. It is a great price for the best fixture in its class.