Rent-a-roof Solar, batteries and EV charging

[Deleted User]

Welsh_Rarebit said:

I DO have a Smart Meter and MPAN's (whatever they are) for both Electric and Gas.  If I simply use excess electric supplied on a sunny day to charge a storage battery, how is this different to using a fan heater or tumble dryer? I assume no part of the Storage battery installation is physically connected in any way to the solar installation?

Hi, the only thing that really matters here are the terms of your contract. If you agreed not to install a battery without their consent then that's what you agreed and the panel owners are perfectly entitled to hold you to that. 

Also, note that there is a fundamental difference between fan heaters, tumble dryers, EV's and the like and the battery system. The battery system is a form of generation equipment specifically designed to change the way you import and export from the grid and the others are just regular appliances. If you start using generation equipment you effectively impinge on the panel owners' income in a way that you agreed you wouldn't and as such it is fair game for them to enforce the contract you signed up to. 

It may seem a bit tough but that's the way it is I'm afraid.

wrf12345

You can plug a battery charger into a socket and charge a battery but I guess the output (via off-grid inverter) would then have to go to its own circuit rather than via the consumer unit, if you have high consuming stuff in the same location then a fairly simple circuit might suffice. So you can charge the battery from solar without affecting the installation and you can charge on cheap TOU tariffs but you can't connect it into the consumer unit and back to the grid for export money, as this might interfere with the solar installation (not entirely sure why). A major advantage would also be that you have electricity if there is a blackout. Using the battery in an EV might also suffice, depending on how it has been designed. You are probably going to lose 25 percent of the power generated by solar via inverters and charger losses but as the solar is free does that matter? A 1kw (allowing for losses) system would roughly cost £200 plus the new circuit (which is almost zero DIY) and can be scaled up as funds allow.

Qyburn

An AC coupled battery won't interfere with FIT generation payments. Battery charging will just appear as a house load, and discharge as a reduction in load and in import.