Energy IndependenceSolar PV
Sizing an Off-Grid Solar Array From Real Load Data
How to Size an Off-Grid Solar Array From Real Load Data
12 minIntermediate
Renewable Energy
The Blackout-Proof Basement
Eight 415W panels, a 60A MPPT controller, 5 kWh of LiFePO4 storage and a 3 kW inverter — the exact stack running our workshop.
What you get out of it
Your fridge, well, lights and internet keep running for two full days without the grid — and you shave roughly $1,900 a year off the bill the rest of the time.
This is for you if…
- You've lost power more than once in the last two years
- You want to start with backup, then expand to whole-house
- You can turn a wrench but you're not an electrician
What you get
- 8 × 415W monocrystalline panels$2,960 value
- 60A MPPT charge controller$640 value
- 5.1 kWh LiFePO4 battery$2,450 value
- 3 kW pure sine inverter$1,180 value
- Combiner box, breakers and PV wire$520 value
- Wiring diagram, permit pack and sizing worksheet$890 value
- Winter sizing walkthrough video$300 value
Total value$8,940
Your price$4,890
Itemized, so you can check our math
- 8 × 415W monocrystalline panels
- 60A MPPT charge controller
- 5.1 kWh LiFePO4 battery
- 3 kW pure sine inverter
- Combiner box, breakers and PV wire
- Wiring diagram + sizing worksheet
Specifications
- Array: 3.32 kW STC
- Bus voltage: 48V
- Usable storage: 4.6 kWh
- Continuous output: 3,000W
- Surge: 6,000W for 5s
Why it's specified this way
The kit we hand to first-time off-grid builders. It carries lights, a chest freezer, a well pump and a laptop day-to-day, and it expands cleanly to a whole-house bank later because the bus voltage and controller are already sized for it. Every component here has been on our mountainside for at least three winters.
"The sizing worksheet told me I needed half the array the installer quoted. I built it myself over two weekends and my last twelve bills total $214."
Dana Whitfield
Boone, North Carolina
4,180 kWh produced · $2,340 saved in year one
$4,890$5,290
4.87 ★ from 63 reviews · In stock
Lights-On Guarantee — if it doesn't work the way this page says, tell us within 365 days and you get your money back. You keep the guides.
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