I bought a Growatt SPF 5000 ES, 16x EVE LF280K grade B's and Daly 150A BMS, with the intention of running my house (all of it) off cheap off-peak electricity by charging the batteries overnight and discharging them during the day. The option of adding solar panels later is a nice to have, and the main selling point for this unit is a real time clock and ability to set up a charging time window for mains -> batteries.
I've just had a sparky out to survey the work for wiring it into the house, and there's a problem.
Though he kindly complimented my tidy battery job; he is convinced (and made a convincing argument, pointing his screwdriver convincingly at things), that the unit will not work for any more than a 5kW system. I thought that 5kW was just the solar/battery inverter and it would just automatically switch back to mains if you exceeded 5kW draw, but he pointed (with his screwdriver) to the AC input and output terminals, described the wire gauges that would be necessary to safely handle the usual British 63A, and said they will not fit into those terminals, so that's basically that.
He will do a bit more research to confirm his understanding (which is the same as mine; that the unit goes inline between the meter and consumer unit and the house is effectively "off-grid, grid-suppliable"), but otherwise thinks that I need an inverter with load sensing that can provide up to its maximum draw to supplement the incoming grid, and not back-feed into the grid, and some more intelligence in the consumer unit might be needed to prevent back feeding in the event of a power cut.
Is this assessment correct? If so, can anyone recommend a unit that will do the job? (charge a 48V battery string overnight on a timer, take solar panels later, and not stop working if I put the oven, washing machine and dishwasher all on at the same time?)
I've just had a sparky out to survey the work for wiring it into the house, and there's a problem.
Though he kindly complimented my tidy battery job; he is convinced (and made a convincing argument, pointing his screwdriver convincingly at things), that the unit will not work for any more than a 5kW system. I thought that 5kW was just the solar/battery inverter and it would just automatically switch back to mains if you exceeded 5kW draw, but he pointed (with his screwdriver) to the AC input and output terminals, described the wire gauges that would be necessary to safely handle the usual British 63A, and said they will not fit into those terminals, so that's basically that.
He will do a bit more research to confirm his understanding (which is the same as mine; that the unit goes inline between the meter and consumer unit and the house is effectively "off-grid, grid-suppliable"), but otherwise thinks that I need an inverter with load sensing that can provide up to its maximum draw to supplement the incoming grid, and not back-feed into the grid, and some more intelligence in the consumer unit might be needed to prevent back feeding in the event of a power cut.
Is this assessment correct? If so, can anyone recommend a unit that will do the job? (charge a 48V battery string overnight on a timer, take solar panels later, and not stop working if I put the oven, washing machine and dishwasher all on at the same time?)