The Sun Bank

Solar panel array with battery storage as the primary renewable generation and storage rig. MPPT controllers, battery bank (LiFePO4 preferred), inverter, and includes solar thermal for water heating where it makes sense.

Footprint Roof + battery closetPanels (typically 1–10+ kW), charge controllers, inverter/charger, battery bank in dedicated ventilated space. Yield Varies by array and location2–20+ kWh/day average; designed to cover critical loads through 3–5 cloudy days with battery buffer. Cycle DailyCharge by day, draw from battery at night or low sun. Seasonal variation normal; sized for worst month.

Cost tier substantialDifficulty seasonLand lotRisk mediumFirst benefit ~14 days

② The Manifest

The parts list. Cores are what you actually need; “if you prefer” opens cheaper, local, or heritage swaps — never budget fallbacks, just other good ways.

PV array

Monocrystalline panels (high efficiency, 400W+ each) with wind/snow-rated racking~$0.25–0.50/W (panels) + racking/labor

South-facing, tilt for latitude or seasonal. Oversize slightly for degradation and bad weather.

if you prefer… (1)

Polycrystalline or thin-filmlowerLower cost, lower efficiency — acceptable for very large arrays.

Charge controllers

MPPT controllers (one per string or as designed)~$100–300 each

Extracts maximum from panels. Multiple controllers add redundancy.

Battery bank

LiFePO4 (LFP) with BMS, sized for 2–5 days autonomy at critical load (10–30+ kWh usable)~$150–300/kWh usable

LFP is the sovereign choice: long cycle life (3,000–6,000+), safe chemistry, good low-temp performance. Never use lead-acid for daily cycling if avoidable.

if you prefer… (1)

Other lithium chemistriesvariesOnly if LFP unavailable; verify safety and cycle life.

Inverter / charger

Pure sine wave inverter/charger sized for surge (pumps) and continuous critical load~$500–2,000+

Must handle worst-case simultaneous draw. Hybrid models that can integrate generator (Backup Rack) are useful.

Solar thermal (optional but high value)

Flat-plate or evacuated-tube collectors + heat exchanger for DHW or space heating preheat~$500–2,000 installed

Free heat that reduces electrical load on the battery bank. Can share roof with PV.

if you prefer… (1)

DIY batch collector or thermosiphon$100–500Lower performance but very low cost.

Monitoring and controls

Battery monitor (SOC, voltage, current), production/consumption meters, simple data logging/display~$100–400

You must know what the system is doing in real time and over time.

if you prefer… (1)

Basic voltmeter + shunt + notebookvery lowWorks if disciplined.

Safety and disconnects

DC and AC disconnects, fuses/breakers, surge protection, proper grounding and labelingincluded in proper install

Solar + batteries can kill or burn the house if wired wrong. Follow code and label clearly.

③ The Sequence

01Audit and right-size the loads first1–3 days (ongoing as audit matures) Before buying panels, do the Efficiency Audit. Label every device's draw. Eliminate waste. Insulate. Use efficient appliances. The cheapest watt is the one you never generate.
02Design the array and mountingPlanning 1 day + install 1–4 days Calculate kWh needs for critical loads + 30–50% headroom. Choose panels, racking, orientation (south, tilt for latitude or seasonal).
03Install charge controllers, batteries, and inverter2–5 days MPPT controllers. LiFePO4 bank with BMS sized for 2–5 days autonomy. Inverter/charger for surge and continuous load. All in dedicated cool/dry/ventilated space with proper fusing and fire safety.
04Add solar thermal if it fits1–3 days Collectors for DHW or space heating preheat. Tie into existing water heater or dedicated loop. Free heat that reduces battery draw.
05Wire the critical loads and transfer logic1–2 days Critical loads on dedicated sub-panel or transfer switch. Sun Bank powers them preferentially. When battery low, signal Backup Rack or shed non-critical loads.
06Monitor, maintain, and document the 'sun first' disciplineOngoing + seasonal review Install monitoring. Maintenance calendar (clean panels, check connections, battery health). Rule: use sun while shining; store what you can; only call combustion when battery critically low and no sun forecast.

⑤ The Echo

A Watt Saved Is a Watt You Never Have to Generate13 min

Why the Sun Bank must be sized after the Efficiency Audit, not before. The physics and economics of generation vs conservation. Over-sizing generation to cover waste makes the whole Power domain fragile and expensive.

The Battery Is Your Real Fuel Tank11 min

Why storage is the hard part, not the panels. Cycle life, DoD, temperature, nameplate vs usable. LiFePO4 changes the game for long-term sovereignty. The battery is what lets you sleep through the night and the cloudy week.

⑥ Feeds

How this rig connects to the rest of the Ark.

→ energy The Whisper Node Solar → charges mesh nodes
→ energy The Relay Tower Solar → powers mesh repeaters
→ energy The Base Station Solar → powers HAM setup
→ energy The Shelf Stack Solar → powers hydroponic pumps and grow lights
→ energy The Living Shelf Solar → powers aquaponics pumps and grow lights
→ energy The Pump House Solar → powers backup well pump
→ energy The Bench Solar → charges tool batteries
→ energy The Base Station Solar array and LiFePO4 battery bank provides grid-independent 13.8V power for indefinite HF station operation during prolonged grid failure
→ energy The Gray Link Solar array and battery bank powers Starlink dish and router during grid failure — 40-75W draw means a modest solar setup provides indefinite off-grid internet
→ energy The Ark Mirror Raspberry Pi draws under 5W — a small solar panel and battery keeps the Ark Mirror running indefinitely off-grid, serving knowledge when everything else is down
→ energy The Ark Vault The Ark Vault draws under 5W; a small solar panel and battery keep it serving knowledge indefinitely off-grid, with no power-grid dependency to compromise its isolation
→ energy The Porch Garden Optional but valuable for full Path B builds — 12V DC exhaust fan, drip irrigation pump, supplemental winter lighting; solar-direct integration possible so the fan runs only when the sun is hot enough to need it

Power · The Sun Bank · power/sun-bank Offline? Same path on any Ark Mirror.