Our system - details

The system that we ultimately purchased consists of the following:

  • 14x Longi 400Wp all-black panels on south facing roofs. Twelve on the main roof and two on a smaller roof over the garage.
  • Bird guarding on all panels.
  • An 8kW Sunsynk Inverter, mounted in the loft.
  • 2x 5.32kWh Sunsynk LiFePO4 batteries, also in the loft.
  • Tigo optimisers for the two panels on the small roof, which are shaded for part of the day.
  • A Tigo Access Point which communicates with the optimizers. This is connected by wire to a Wifi gateway which communicates with the network
  • The system will stop sending power to the house in a power cut, but there are sockets (in the living room) on the essential loads (UPS) output of the inverter.
  • A contactor deals with the situation where the grid neutral (and hence the earth) goes away in an outage. The essential loads then needs a N-E tie.

The 8kW inverter is overkill for this size of instalation. It was chosen to allow future expansion. In particular, I would like to experiment with panels on other roof surfaces. In some cases, even north faving roofs can generate useful amounts of power If electricity becomes much more expensive this may be useful.

Our experience with the supplier/installer were mixed, although I think that, overall, I would recommend them

Pros:

  • The salesman was knowlegable and was open to some of my wilder ideas.
  • The company handled all of the necessary paperwork, including a G99 (at extra cost).
  • The scaffolding company, panel installers, and electrician were all pleasant, polite, and tidy.
  • Remedial work was carried out in a timely manner, without push-back.
  • The cost was competetive, although probably not the lowest possible.
  • The system has performed above expectations since it was installed.

Cons:

  • It took four months from ordering to installation. This was due to the need for a G-99, but also due to excessive interest in SolarPV and a shortage of equipment. By current standards, four months might even be good!
  • Initially, my plan to put some panels on the north-facing roof was acceptible to the installer as long as I acknowledged that I was getting them in the full knowledge that the output would be very low. However, ultimately, they backed out of doing this for me on the grounds that they had a "company-wide policy" not to install any north-facing panels. Personally, I think that it would have been very interesting to see if I could get the 50%-60% that I would expect from such panels.
  • There were technical errors in the installation which should not have occurred. They did not compromise the operation of the system, but I felt that there were inadequate protection features in the initial installation. I put this down to an electrician inexperienced with the particular set-up and/or miscommunication.

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