In 2018, before we had a battery, we used 8323kw of electricity.
In 2020 with battery and iboost we used 7025kw
Saving 1298kw, or £205.00 per year on our present tarif. So the pat back on the additional battery would be at at least 7 years.
So I think we shall forget the additional battery.
Electricity prices would have to rocket to make it a 5 year ROI.

Peter,
66, 2016 Porsche Boxster S
No longer driving Tarka, the 2014 Plus 8...