Draft — pending review

This guide’s safety-bearing prose is awaiting owner sign-off (docs/07 §43); it isn’t indexed or listed publicly yet. The parts list is engine-validated.

A weekend off-grid cabin system

EG4 3000EHV · 48V · ~2 days of autonomy for lights, a fridge, and devices

This is the system we recommend for a typical weekend cabin: enough to run LED lighting, a full-size fridge, and charge phones and laptops, with roughly two days of stored energy for cloudy stretches. It is a 48-volt off-grid build — no grid connection, no export.

Every part below has been checked against the others by our compatibility engine: the panel string voltage stays inside the inverter’s MPPT window even on the coldest morning, the battery speaks the same closed-loop language as the inverter, and the wiring and protection are sized with the NEC 125% continuous-duty factors already applied.

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Wiring & protection (5, auto-sized) — $880
  • 1× Class T 400A Fuse + 5502100 Holder$120
  • 1× 2AWG Inverter-Battery Cable Kit$35
  • 1× IMO SI25-M4 DC Disconnect$85
  • 1× Solar Grounding Kit (6 AWG bare copper + lugs + ground rod clamp)$40
  • 1× SS 6-Panel Ground Mount Row (pipe-based)$600

Total: $5,602

7.4 kWh/day · 8.2 kWh usable · 3,000 W · ~2.5 days

Opens an editable copy — change any part and the compatibility engine re-checks live.

Why this inverter

The EG4 3000EHV is a 48V all-in-one off-grid inverter with a built-in MPPT charge controller, so panels connect straight to it — no separate charge controller needed. Its 3,000 W continuous output comfortably covers a cabin’s simultaneous loads, and its ~35 W idle draw is charged into the sizing so the numbers stay honest.

Why two batteries

Two EG4 LifePower4 modules give 10.2 kWh of nameplate LiFePO4 (about 8.2 kWh usable at 80% depth-of-discharge). That is sized for ~2 days of autonomy at this cabin’s daily demand, and it also satisfies the inverter’s charge/discharge current needs — a single module would bottleneck them.

What this guide does not decide for you

Compatibility is not code compliance. This build checks that the components work together electrically; it does not check your local permit requirements, structural mounting for your roof or ground, or utility rules. Low-voltage off-grid systems are installed by many DIYers, but a fixed ground mount may still need a county building permit — a quick call to your building department settles it.

Prices update automatically from tracked retailers; verify at the retailer before buying. This guide checks electrical compatibility between components, not code compliance for your install. What we don’t check →

Updated 2026-07-18.