Dazza101

Hello. I am due to get a 5KW system spreed between my SW roof and S facing garden in Feb. Along side this will be 10Kw ‘9kw usable’ of batteries. I’m looking at possibly trying to figure out a way to either preheat cold feed going into combi boiler ‘might need a different boiler but it’s 15 years old’ or preheat cold mains feed going into 10.5 Kw shower. Anybody recommend a way to preheat water to set temp in either from excess power from PV’s? A question on solar array. If on a bright sunny day I’m producing 4.5KW and fire up 10.5KW shower, do I just draw 6kw from the grid? That might be a daft question? lastly has anybody have any experience with PureDrive batteries? Dc 5kw x2. Many thanks