Today I’ve been charging my electric car (a BMW i3) for free using the solar panels on the roof of my house.

While such an approach seems obvious, it is actually difficult to achieve for most homeowners because solar power is variable (even on a sunny day clouds will pass in front of the sun and power will reduce) while electric cars need a constant minimum power to charge.


There are an increasing number of sophisticated intelligent charge points coming on to the market that are designed to manage this process (the MyEnergi Zappi is the leading example). They attempt to maximise the use of the available solar power, and minimise the amount of additional grid electricity used to keep the charge going. However, when power reduces significantly their only option to avoid using a lot of grid electricity is to stop charging.

I would like to show that there is another way to achieve optimised solar charging of an electric vehicle for free, and it uses a device that is increasingly common in solar homes – the home battery (our PowerBanx, for example). The rate of deployment of such systems is increasing fast across Europe, the US and Australia in particular, and provides the means of charging an electric car for free without additional infrastructure, or even a conventional charging point.

Read more: LinkedIn