Solar storage review

Solar storage review
  1. Awaiting approval
  2. Victron can power critical AC loads on their own circuit
  3. Works only on a single PV string
  4. Inverter charger must be larger than PV size
  5. Need an external relay to make it comply, costing about £1,000
  6. Only works with single inverter so max PV depends on existing inverters
  7. Can add an additional 6.4kWh battery bank
  8. Can add multiples of batteries sizes available
  9. The Moixa battery system has DC outputs to connect LED lights as backup lighting in event of power cuts

4kW+ PV system

Tesla Powerwall + SolarEdge

  • 6.4kWh of capacity ideally suited to 4kW of PV.

  • Expected longer battery life due to liquid and air cooling

  • Simple design

  • 3.6kW of continuous power to run immersion heater and kettles which are typically 3kW

  • 10 year warranty on battery

2kW PV system

Darfon + Growatt

  • 2kWh or 4kWh of usable capacity ideally suited to 2kW of PV.

  • Simple design

Electric car or Aga

Wait for Tesla Powerwall 2

  • The 14kWh Tesla Powerwall 2 is more suited to charging the large electric car batteries of 30kWh+.

  • The existing Tesla Powerwall 6.4kWh model will continues to be manufactured to cost effectively meet the demands of most UK households.

Regular powercuts

Wait for Tesla to release backup system

  • The Tesla Powerwall system can be installed as a backup system in many other countries and Tesla are hoping an agreement can be reached with the Distribution Network Operators to make it easy in the UK.

Expected savings

The expected savings for the average 3 bedroom home is £344 per year

Calculations

Assumption Unit Value
Energy from PV system kWh 4,328
Current use of PV in home 35%
Use of PV in home with battery 85%
Units of energy saved kWh 2,164
Financial benefit of energy saved £ 344

Assumptions

  • Cost of electricity is 16p per kWh

  • South facing system installed in Devon and Cornwall at 30 degree pitch

  • Electricity prices fixed (increased energy prices would increase the savings)