Cables / Tender:
=> $912 total
Remote tracking (optional):
How to guide
Coming soon, for now refer to Will Prowse’s wiring guide on his very-similar 48V 3000W off-grid solar system which I followed and works great for me!
Financial Payback & Embodied Energy
Financial payback period for 3000W
System cost : $1,124 on Amazon in 2024 (now $912)
Yearly energy creation: 365d * 4.26hsun/d * 1.280kW = 2,000kWh/y (but more like 1,000kWh/year after losses)
Yearly value creation: 1,000kWh/y * $0.55/kWh in SF = $550/y energy created
100W system payback period: $1,124 / $550 = 2 years until payback
How green is it:
Production footprint PV (source):
2,900kWhee/kW * 1.28kW = 3,712kWh embodied energy
Production footprint LiFePo4 battery (source):
106kWhee/kWh * 2.4kWh = 254kWh embodied energy
Annual energy production system: 1100kWh/y
Payback period: 3966kWh / 1100kWh/y = 3.5 year footprint payback
FAQ
What’s the catch? Seems to good to be true? Well, this thing sits between your devices and the wall. So you need to neatly run extension cables from every room in the house to the “sun box”, and then run one cable from the box to the panels, and another to the wall (optional, just so it can fall back to pulling power from the wall). Photos of this are coming soon.
Will it ever push power back into the wall? Nope! It’ll only ever draw from the wall in the event that both the sun is down and the battery is dead (so your fridge won’t go off overnight for example).
Is this legal? Yes, see above. No difference to plugging your fridge into your wall, as far as the utility is concerned.