Pushed to new heights
A 20 kW device made by Growatt, the 20000TL3-HE, is only the second inverter tested by PHOTON Lab to achieve a conversion efficiency higher than 99 percent. The device scores third place overall, even without silicon carbide transistors
When combing through the PHOTON database for all inverters currently available on the market worldwide, only isolated devices can be found whose manufacturers promise a conversion efficiency of 99 percent or higher. Spanish manufacturer Jema Energy SA, for example, specifies 99 percent for its IF- 225 TL plus, a 275 kW central inverter. In the category comprised of lower capacities, this issue’s test candidate, the 20000TL3-HE made by Growatt, is the only device whose manufacturer promises 99 percent. This device was given to the PHOTON Laboratory in October 2013, and the obligatory test agreement was signed.
The 99-percent mark was broken for the first time a few years ago by the Sunny Tripower STP 20000TLHE-10, for which its manufacturer, SMA Solar Technology AG, specified 98.5 percent (see PI 12/2011, p. 140). However, the SMA inverter made it to 99.15 percent only after the reverse current diodes had been deactivated – when the protective diodes were operating, its efficiency was slightly below 99 percent. Furthermore, SMA used silicon car- Pushed to new heights bide transistors, while Growatt manages without utilizing this silver bullet. Of course, very good conversion efficiency is, on its own, not an adequate criterion for judging what is a very good inverter overall. Being able to break the 99-percent mark, however, shows that the manufacturer is playing in the technological major league.