Can XLE storage heaters be connected directly from a solar PV system and divert power to the heater?

There is no current way of making the XLE heaters take a charge when there is excess solar electricity available. 

Solar diverters cannot be used with XLE as they typically work by varying the voltage going to the heater elements. 

It is important to remember, the kW load of our XLE heaters and the potentially long charge times needed to properly charge XLE are usually much greater than the spare capacity of most UK domestic solar panels as to not make it worthwhile. 

Solar PV Panels typically produce a lot less power in winter than in summer. XLE heaters on the other hand use lots of power in winter and are typically switched off during the summer. Using a solar diverter to heat a basic electric hot water tank element with the excess solar energy makes more sense as hot water is used all year round.