Output and efficiency: 15 HPS lamps tested

HPS lighting for plants is standard in professional horticulture: Not only does the low acquisition cost per square meter make HPS lighting a cost-effective lighting solution for plant cultivation, but the industry can also build on over 20 years of experience with HPS technology.

Currently, a wide variety of HPS lamps from various brands and manufacturers are available on the market in various price segments. In addition to established brands like Sylvania, OSRAM, and others, there have been an increasing number of brands and products in the low-price segment, especially in recent years.

We asked ourselves the following questions:

• How do the different light sources perform in terms of performance and efficiency?
• Are there differences in the performance of branded products and private labels?
• Do the test results correspond to the information provided by the manufacturers on the data sheets and product packaging?
• How competitive is one of our top sellers among the HPS lamps, the Sylvania Grolux SHP-TS 600W 230V compared to other products on the market?

To explain: HPS lamps are like NDL lamps – HPS stands for “High Pressure Sodium” and NDL for “sodium vapor lamp”

The test scope:

There were 600W 230V HPS lamps with E40 socket from 15 brands from different manufacturers We tested and compared lamps from different manufacturers and price ranges. The retail price of the cheapest lamp was €25, while the most expensive lamp was €59.

The lamps were ordered from various dealers; the selection of lamps did not follow any fixed rule, but rather was intended to represent a cross-section of the HPS lamps commonly used today.

This also ensures that no manufacturer provides a specially prepared version of its lamp for testing.

The test procedure:

To ensure a consistent basis for comparison, the "burn-in" of new HPS lamps is important for consistent output and to avoid significant fluctuations in performance. Some manufacturers perform this process themselves, while others leave it to the customer.

For the test, the lamps were burned in for 100 hours using an IES (Illuminating Engineering Society)-compliant ballast. This device ensures that the lamps burn in neither too quickly nor too slowly. It also ensures that the burn-in phase is not dependent on a specific ballast manufacturer.

The test in the Ulbricht sphere:

For the test, the lamps were connected to their respective ballasts and operated centrally in an integrating sphere to ensure good comparability of the measurement results. The PPF value was measured in µmol/s, i.e., the photon flux or the amount of light usable by plants.

One integrating sphere Due to its optimal reflection properties, it enables an accurate measurement of the total PPF output in µmol/s of a light source and is used as standard in scientific light measurements.

Since, unlike the absolute PPF output, the relative PPFD value depends on many other factors such as the reflector, reflective walls, the floor, the ceiling, or the distance from the lamp to the measuring head, only the PPF value was measured. The data analysis was automated, and all measurement data was stored in a database.

The ballasts used – magnetic vs. electronic

A ballast is required to ignite HPS lamps and supply them with power during operation. Ballasts come in two types: magnetic ballasts (MVG) and electronic ballasts (EVG). Magnetic ballasts are usually inexpensive and very durable, but they have somewhat higher power consumption and are each designed for a specific wattage.

Electronic ballasts have a power factor of up to 0.98 and are also dimmable, making them suitable for different wattages.

In the test, two ballasts were chosen as representatives of their design.

Magnetic ballast:Electronic ballast:

Eurogear Pro 600WDimmable ECG 400-600W (symbol image)

The results:

PPF measurement on the magnetic ballast

The majority of the 15 lamps tested on the Eurogear Pro 600W magnetic ballast showed higher PPF values ​​than on the electronic ballast. The Sylvania SHP-TS Grolux 600W achieved the highest PPF value with 1,132 µmol/s and was still 52 µmol/s stronger than on the electronic ballast.

Efficiency of the magnetic ballast

When measuring efficiency, almost all lamps tested achieved the same or slightly higher efficiencies with the magnetic ballast than with the electronic ballast. Here too, the Sylvania Grolux SHP-TS 600W achieved the best value with 1.81 µmol/s/W among the 15 lamps tested .

PPF measurement on the electronic ballast

The different lamps performed on the electronic ballast with PPF values ​​ranging from 925 to 1080 µmol/s. Only four of the 15 lamps tested achieved a PPF value higher than 1000 µmol/s. The Sylvania SHP-TS Grolux 600W had the highest output at 1080 µmol/s.

Efficiency of the electronic ballast

In terms of efficiency, the different lamps showed very different values ​​ranging from 1.55 to 1.78 µmol/s/W. The Sylvania SHP-TS Grolux 600W achieved the second best efficiency with 1.77 µmol/s/W .

Lamp No. 5 achieves the peak value of 1.78 µmol/s/W. It was specifically optimized by the manufacturer for operation with electronic ballasts and was the most expensive of the lamps tested.

Results:

Maximum output – the PPF value

The relatively large fluctuations in output between the various 600W lamps of the tested brands were striking. This was the case both with the magnetic ballast (Δ 224 µmol/s, min. 908, max. 1,132) and with the electronic ballast (Δ 155 µmol/s, min. 928, max. 1,080).

None of the 15 lamps tested had a PPF output below 1050 µmol/s according to their data sheet. In fact, only five manufacturers achieved the stated output in the magnetic ballast test, and only two in the electronic ballast test. Lamp No. 9, with a measured PPF output of 928 µmol/s, was even 12% below the PPF output stated in the data sheet.

The Sylvania Grolux SHP-TS 600W exhibited the highest output across both ballasts. With the magnetic ballast, it achieved a very good efficiency of 1.81 µmol/s/W, which even rivals some LED luminaires. With the electronic ballast, it also performed very well, achieving 1.77 µmol/s/W.

Efficiency:

When measuring the lamp current (the lamp's power consumption), it became clear that the electronic ballast operates more efficiently. In the mid-range of the candidates, this marginally reduces the overall output but increases efficiency.

The magnetic ballast delivers the maximum amount of energy the lamp's burner can utilize. This isn't necessarily energy-saving, but some lamps benefit greatly from this.

Three (ECG) and four (MVG) lamps had an efficiency of less than 1.6 µmol/s/W, while four lamps each achieved an efficiency of more than 1.7 µmol/s/W. The Sylvania Grolux SHT-PS 600W 230V achieved very good values ​​on both ballasts with 1.77 and 1.81 µmol/s/W respectively.

Recommendation – Best practice:

In terms of both output and efficiency, the Sylvania Grolux SHP-TS 600W 230V performed best in direct comparison with all other lamps. In combination with the magnetic ballast Eurogear Pro 600W It represents an exposure solution with very good performance, high efficiency and long service life.

Disclaimer

Unfortunately, we cannot disclose the names of the tested lamps. Like any technology, HPS technology is subject to certain fluctuations in production, so the measured values ​​do not represent a universally valid measurement, but correspond to the lamps tested at the time of testing.