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Off-grid system cost

Rough budget across panels, batteries, inverter, charge controller, and mounting hardware. Pulls together what the sizing calcs tell you into a real dollar number.

Off-grid system cost budget + payback

System size

From the array sizing calc, or your existing panels.
Ah × system voltage. For payback math what matters is nameplate cost.
From the inverter sizing calc. Surge rating doesn't drive price much.
Auto-suggest: panel watts ÷ system voltage. 800W / 24V ≈ 33A → 40A controller.

Per-unit prices (USD)

$200-300/kWh is current for new LiFePO4. DIY cells drop to $100-150.
$0 for DIY install. $3000-6000 typical for pro install of a 2kW system.

Payback math

How much grid electricity the system replaces. From the running-cost calc, or your last bill.
Total system cost --
Itemized breakdown
  • Enter system size to see breakdown.
Monthly grid savings --
Payback period -- --
Notes --
All prices in USD. Adjust per-unit rates to your local market. Defaults are mid-2025 North American hobby-channel pricing. Mounting, wiring, and labor are the most variable items; if you're getting a real quote, those line items will look very different from the defaults.

What this is for

The other solar calculators on this site tell you what size system you need: how many panel watts, how much battery Wh, what VA inverter. This one multiplies those numbers by realistic component prices and tells you what the build will cost.

Use it to figure out whether a small off-grid setup makes financial sense versus just plugging into the wall.

What the numbers assume

Default per-unit prices are mid-2025 hobby-channel pricing for North America (Signature Solar, Renogy, AliExpress for cells, etc). They'll be off by 10-30% from what you actually pay, in either direction. Adjust the inputs to your real quotes.

  • Panels: $0.40-0.80/W is current for monocrystalline rigid panels. Cheap end is bulk pallets; expensive end is single-panel retail.
  • LiFePO4 batteries: $200-300 per kWh in 2025. Used or DIY drops to $100-150/kWh. Old-stock lead-acid runs $100-150/kWh nameplate but you only use 50% of it.
  • Inverters: $0.10-0.30 per watt of continuous output. Pure sine wave at the higher end.
  • Charge controllers: MPPT runs $1-3 per amp of output rating. A 60A MPPT is $80-200.
  • Mounting and wiring: highly variable. Roof racks for 4-8 panels cost $300-600 in hardware. Ground mounts double that.
  • Install labor (optional toggle): a DIY install costs $0 and a weekend. A pro install for a 2kW system runs $3000-6000 depending on roof access and local labor rates.

Payback math

The "years to payback" output compares the total system cost against what you'd save on grid electricity over time. If your aquaponics setup pulls 100 kWh/month and grid power is $0.15/kWh, the system saves $180/year, and a $3000 build pays for itself in 16-17 years.

That's a long time. Off-grid solar usually doesn't beat grid power on cost alone unless your grid rate is high (Hawaii, parts of California, much of Europe and Australia) or you'd have paid for new utility service anyway (rural land, outbuildings far from the meter).

What off-grid actually buys you: independence from the grid going down. For aquaponics with pumps that can't lose power for more than a few hours without crashing the biofilter, that's worth real money. The calc treats this as backup-value separately if you toggle it on.

Further reading