Hi all - I'm planning to expand my existing solar system. Proposed design below (based on Sunsynk's standard 'On-Grid+AC couple' operation mode stated in their manual)
The 4kW of Sharp panels, 3.7kW inverter and generation meter is an UK Feed In Tariff (FIT) system I’ve had since 2011. The expanded system is designed so that:
1) My FIT provider remains happy (which they are – as long as the generation meter stays where it is!)
2) Generation from that inverter is never limited (the generation rate is very good)
Our house is almost entirely electric (including heat pumps and EV) and we use a lot of power. I expect to expand the battery stack when I can afford them.
Some questions:
The 4kW of Sharp panels, 3.7kW inverter and generation meter is an UK Feed In Tariff (FIT) system I’ve had since 2011. The expanded system is designed so that:
1) My FIT provider remains happy (which they are – as long as the generation meter stays where it is!)
2) Generation from that inverter is never limited (the generation rate is very good)
Our house is almost entirely electric (including heat pumps and EV) and we use a lot of power. I expect to expand the battery stack when I can afford them.
Some questions:
- Regarding the Backup Load, the Sunsynk 10K manual states 60A AC passthrough. I take this to mean that it can supply around 14kW directly from grid to the Backup Load (if necessary, assuming no Solar or Battery to use). That should be enough for the house (worse case if we had baseload + 4x 3kW heater loads such as Oven+Dryer+Kettle+Heater it might trip, but I think that would be rare). However, I’ve read conflicting opinions on the maximum Backup Load before the inverter trips. Some say it will trip at the headline Inverter rating, not the Passthrough rating, which seems odd. Potentially a limitation of older systems? Has anyone know for sure, or have a recent system found that the inverter trips when Backup (UPS) Load exceeds the headline inverter rating?
- Also, I note that the 8kW Ecco inverter has 50A AC passthrough. If I used 2x 8kW inverters in Master-Slave, would they parallel the capacity, enabling 100A (23kW) passthrough from grid to backup Load?
(As an aside, that's quite tempting as I'd also gain an extra MPPT. The new 11kW panels have a block of shade which creeps over in the afternoon - I'm hoping the claimed improved optimisation of the Aiko panels will deal with that without having to pay for optimisers, but if I have another MPPT I could break that up more to further reduce the impact).
- Finally, I presume this design leaves the House at risk of no power if the Sunsynk fails? Presumably, I could simply add a changeover switch to allow connecting the Backup Load directly to the grid to bypass the Sunsynk if necessary?
- Any other comments/concerns about the design?
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