- Daily output
- Solstice Energy
1) 14 Yingli 235 watt panels
2) SMA SB3000 Inverter
3) SMA datalogger (Webbox)
4) Elster A100C Generation Meter
5) DC and AC isolating switches
The location is Belvedere in the borough of Bexley on the SE London/Kent border, the roof has a 30º inclination totally unshaded and about half a degree east of due south.
A transformerless inverter was rejected because the existing earthing arrangements would have required extensive and expensive modifications and the cost together with additional cost of the inverter when compared with the anticipated improved efficiency pushed pay back time beyond the inverters probable life. The fact that the transformerless variant of the SB3000 was subject to a six week supply delay was also a factor.
A 3kW inverter was chosen for 3·29kW panels on the advice of the installer who produced performance curves which showed that greater efficiency was obtained by keeping the inverter operating close to its limits and that the output on days when 3·3kW might be achieved was outweighed by the extra efficiency obtained on less than perfect days.