⚡ Energy Creation & Management

1. Solar Power Systems

How PV Solar Works

Photovoltaic (PV) panels convert sunlight to DC electricity. A charge controller regulates voltage to safely charge batteries. Batteries store energy. An inverter converts stored DC to AC for household appliances.

System Sizing

Step 1: Calculate your daily load in watt-hours (Wh)

Step 2: Size the panel array

Formula: Daily Wh ÷ Peak Sun Hours (PSH) ÷ System Efficiency (0.85) = Panel Watts Needed

Add 25% safety margin → 200W panel array. A single 200W panel or two 100W panels in parallel.

Step 3: Size the battery bank

For 3 days of autonomy (no sun) without discharging below 50%:

At 12V: 3,300Wh ÷ 12V = 275Ah. Two 150Ah 12V lead-acid batteries in parallel, or one 200Ah lithium (LiFePO4 — deeper discharge, lighter, longer life).

Charge Controllers

Wiring Basics

• Series wiring (panels): Connects + to −. Voltage adds, current stays same. Two 12V/8A panels in series = 24V/8A.
• Parallel wiring (panels): Connects + to + and − to −. Current adds, voltage stays same. Two 12V/8A panels in parallel = 12V/16A.
• Wire sizing: Under-sized wire causes voltage drop and fire risk. For 12V systems: use 10 AWG (5.26mm²) for runs up to 10 feet at 20A; 8 AWG for longer runs.
• Fuses/breakers: Fuse every circuit at the battery, sized to 125% of maximum expected current. This is a safety requirement — not optional.

Inverters

• Pure sine wave: Required for sensitive electronics (computers, medical equipment, audio). More expensive.
• Modified sine wave: Fine for resistive loads (heaters, fans, lights). May damage some motors and electronics. Much cheaper.
• Size at least 25% larger than your highest single load. Add a surge capacity of 3× for motor starts.

2. Hand-Crank & Pedal Generators

What You Can Realistically Generate

Human power is best used for high-value, low-power tasks: charging phones, radios, LED lighting, small medical devices. It cannot power large appliances efficiently.

Building a Bicycle Generator

1. Mount the bike: Use a bike trainer stand, or remove the rear wheel and mount the bike on a frame (rear axle resting on a support, rear dropout clamped to a board).
2. Drive system: The simplest approach is to mount a friction drive roller (rubber-covered spindle) against the bike tire. The roller connects to the generator shaft. Tire rotation spins the generator.
3. Generator/alternator: A car alternator (12V, 50–100A) is ideal — widely available, robust, produces 12V DC. Also usable: permanent magnet DC motors (most scooter and drill motors used as generators), stepper motors from printers. At typical cycling speed, you need a gear ratio to spin the generator fast enough — car alternators need 1,500+ RPM.
4. Rectifier (for AC generators/alternators): If using an AC generator or alternator, add a full-bridge diode rectifier to convert to DC. Car alternators have built-in rectification.
5. Voltage regulator: Add a simple 12V charge controller between output and battery to prevent overcharging. Do not connect directly to battery without regulation.
6. Output: Connect to 12V battery bank. Battery smooths the variable output and allows you to rest while loads continue to be powered.

3. Micro-Hydro Power

If you have a stream with sufficient flow and head (vertical drop), micro-hydro is the best off-grid power source — it produces power 24/7, requires no batteries for immediate loads, and is highly reliable with minimal maintenance.

Key Variables

• Head (H): Vertical drop from intake to turbine, in meters. Higher = more pressure = more power.
• Flow (Q): Volume of water per second through turbine, in liters/second (L/s).
• Power estimate: P (Watts) = H × Q × g × η — simplified: P ≈ H(m) × Q(L/s) × 5.5

Basic Pelton Wheel System

1. Intake: Build a small weir (low dam) in the stream. Divert water into a settling tank (removes sediment), then into the penstock pipe.
2. Penstock: Use PVC or HDPE pipe. Larger diameter = less friction loss. For 3 L/s flow, use minimum 2" (50mm) pipe. Keep bends minimal — each 90° bend costs ~10m of equivalent head in friction loss.
3. Nozzle: At the bottom, a nozzle converts pressure to a high-speed jet. Nozzle diameter determines flow rate — adjustable nozzle (ball valve) allows power regulation.
4. Turbine: A Pelton wheel (cups on a wheel that catch and deflect water jets) is most efficient for high-head, low-flow systems. Can be fabricated from steel plate, or cast from aluminum. Spoons/cups can be improvised from cut pipe sections.
5. Generator: Permanent magnet alternator is most reliable. Pair with a full-bridge rectifier for 12/24V DC charging.
6. Load controller / ballast: Hydro runs constantly — you need a ballast load (water heater, resistor bank) to absorb excess power when batteries are full. A shunt regulator diverts power to ballast automatically.

4. Wind Turbines

Wind Power Basics

Wind power varies with the cube of wind speed: doubling wind speed gives 8× more power. Consistent 12+ mph (5+ m/s) average wind is needed for practical generation.

DIY Small Turbine

• Rotor blades: Carve from hardwood (cedar, spruce) or cut from PVC pipe. 3-blade designs are most common. Balance blades precisely — imbalance causes vibration and failure. 1–2m diameter rotor suitable for home build.
• Hub: Steel pipe flange or welded steel plate. Attach blades at 5–8° pitch angle.
• Alternator: Axial flux permanent magnet alternator (PMA) is the standard DIY choice. Build from two steel rotors with neodymium magnets, surrounding a copper coil stator. Plans available from Hugh Piggott's "Windmill Workshop" (search offline or print).
• Tower: Must be tall enough to get above turbulence (typically 10m+ in open terrain). Guyed monopole tower: steel pipe with guy wires at 120° intervals. Base must be concreted. Guy anchors set at 80% of tower height from base.
• Furling tail: A tail vane that swings the rotor out of high winds to protect against overspeed. Angle between tail hinge and rotor axis determines furling wind speed.
• Dump load: Essential — when batteries are full, a dump load (resistor water heater) absorbs excess power. Without it, over-voltage destroys the alternator or batteries.

5. Wood Gasification

A gasifier converts solid biomass (wood chips, charcoal) into combustible "producer gas" (woodgas or syngas) — a mixture of carbon monoxide, hydrogen, and methane — by partial combustion with limited oxygen. This gas can power internal combustion engines adapted to run on it.

Downdraft (Imbert) Gasifier — Preferred Design

Engine Adaptation

Standard gasoline engines can run on producer gas with carburetor modification (add a gas mixing valve in the intake). Power output drops 30–40% vs gasoline. Diesel engines can dual-fuel (70% producer gas, 30% diesel pilot injection) — requires no carburetor modification.

Fuel Quality

• Wood must be dry — <20% moisture content. Wet wood produces excessive tar and reduces efficiency.
• Uniform chip size (2–5cm) ensures even feed and prevents bridging.
• Hardwoods (oak, hickory) gasify more efficiently than softwoods.

6. Battery Maintenance & Improvised Batteries

Lead-Acid Battery Maintenance

Desulfation

Sulfation (lead sulfate crystals coating plates) is the primary cause of early battery death from under-charging. Signs: low capacity, won't accept full charge, low specific gravity.

Pulse desulfation: Specialized charger sends high-frequency pulses that break down lead sulfate crystals. Commercial desulfators ($20–80) work on mildly sulfated batteries. Severely sulfated batteries are generally unrecoverable.

Lithium Iron Phosphate (LiFePO4)

The preferred battery type for long-term off-grid use. Advantages: 3,000–5,000 cycle life (vs 300–500 for lead-acid), 80% usable capacity (vs 50%), lighter, no maintenance, no hydrogen gas. Disadvantages: higher upfront cost, requires a BMS (Battery Management System — almost always included in cells), cannot tolerate freezing during charging.

Improvised Batteries (Emergency / Educational)

These are extremely low capacity and are useful only for demonstrating principles or powering very small loads (LED, watch).

• Galvanic cell (lemon battery): Zinc nail + copper penny in citric acid (lemon) = ~1V, ~1mA. Connect many in series for more voltage. Not practical for useful loads.
• Saltwater battery: Zinc + copper plates in saturated salt water. ~0.8V. Stack many cells. Can temporarily power an LED.
• Earth battery: Zinc and copper rods driven into moist soil 1–2m apart. Very small current but continuous. Can charge a capacitor for intermittent LED flashes.

7. Charging Phones, Laptops & Power Banks

When the grid goes down, keeping a phone, radio, or laptop alive is often the first real problem — for light, information, navigation, and contact. The trick is matching the voltage your device wants to whatever power you can scavenge. Phones are easy (5 V USB); laptops are demanding (≈20 V or USB-C PD) and need a real buffer.

Charging phones & USB devices (the easy 5 V)

• Solar: a folding USB solar panel (10–25 W) charges phones and power banks directly in sun. Charge a power bank in daylight, then charge your phone from it at night — the panel's output is steadier into a bank than into a phone.
• Your vehicle: a 12 V socket (cigarette lighter) + a USB adapter charges phones and banks. A car battery holds dozens of phone charges; you don't even need the engine running for that. Run the engine occasionally (well ventilated) to top the car battery back up — or better, charge while you're already driving.
• Any 12 V battery (car, leisure, solar bank) + a regulated 12 V→USB adapter = a long-lived phone charger.
• Hand-crank & dynamo: wind-up chargers, and bicycle dynamos (hub or bottle) feeding a rectifier + USB regulator, make charge from muscle. A bike + dynamo can put real USB power into a bank.
• Stove / fire (thermoelectric): stoves with a built-in USB output, or a Peltier (TEG) module clamped between a hot pot and a cool sink, trickle a small USB charge while you cook.
• AA fallback: a "4×AA → USB" emergency charger gives a phone a partial charge from cheap cells; pair with rechargeable AAs you top up off solar/car.

Charging laptops (the demanding ≈20 V)

Laptops draw far more, at higher voltage, so you need a battery buffer — don't try to run one straight off fluctuating solar.

• Portable power station (200–500 Wh): the realistic answer. It charges a laptop several times over via its AC outlet or USB-C, and itself recharges from solar, a car, or a generator. The cleanest off-grid laptop solution.
• USB-C Power Delivery (PD): most modern laptops charge over USB-C. A 65–100 W USB-C PD source — a big PD power bank, a 12 V→USB-C PD car adapter, or a PD-capable solar setup — charges them directly and efficiently. Check your laptop's wattage.
• From a car (12 V): a DC-DC "car laptop charger" steps 12 V up to the ~19 V barrel your laptop needs (efficient), or a 12 V→mains inverter runs the laptop's normal charger (simple but wastes ~15–20% converting DC→AC→DC).
• Solar: needs a meaningful panel (60–100 W+) feeding a power station or PD controller — the battery in the middle smooths the supply so a passing cloud doesn't drop your laptop.

Efficiency rule of thumb: a direct DC-DC path (12 V→USB, or 12 V→19 V) wastes less than going DC→AC→DC through an inverter — use DC-DC where you can. Pair this section with Solar Power Systems to make the power, and Battery Maintenance to store it. To size a system, use the Off-Grid Power Calculator.

8. Salvaging & Re-mounting Solar Panels

In a long-term grid-down world, the rooftops around you are a hardware store. A salvaged solar panel, its cabling, and its mounting rails can rebuild your power supply for free — but pulling a panel off a roof is the most dangerous job in this section. The reason is simple and it kills people every year: a solar panel cannot be switched off. In any daylight it is making electricity, and a full roof string can sit at 300–600 V DC — more than enough to stop your heart. Everything below is built around that one fact.

Step 1 — Kill the output

• Cover the panels with something opaque before you start. No light, no voltage.
• If the system has a DC isolator / disconnect (near the inverter or charge controller), switch it off too.

Step 2 — Disconnect the wiring

• Trace the cables down to the inverter, charge controller, or combiner box so you know what feeds what.
• Panels join with MC4 connectors (a cheap MC4 unlock tool separates them) or screw terminals in a junction box.
• Cut one wire at a time, leave long tails, and cap or tape each cut end immediately. Keep your free hand off metal.

Step 3 — Remove the panel (mechanical)

Panels sit on aluminium rails, held down by mid-clamps and end-clamps (hex/Allen bolts). The rails bolt to roof feet screwed into the rafters and sealed with flashing.

• Undo the clamp bolts and lift the panel up and off — don't slide it down the roof.
• They're big (~1.7 × 1 m), 18–25 kg, and the glass is fragile: don't flex it, don't step on it, hand it down rather than drop it.
• Salvage the hardware too — the rails, clamps, feet, and MC4 cabling are as useful as the panel. Grab the charge controller/inverter from inside while you're there.

Step 4 — Test what you took

Set a multimeter to DC volts, put the probes on the two leads, and face the panel at the sun. The open-circuit voltage (Voc) should roughly match the label:

• A small "12 V" panel → ~18–22 V Voc.
• A standard 60-cell ~250–300 W panel → ~37–40 V Voc.
• Cracked glass often still works but lets water in (it will degrade) — usable short-term. Burnt, brown, or delaminated patches = scrap.

Step 5 — Re-deploy it (don't put it back on a roof)

• Far safer and easier: a ground-mounted A-frame, tilted to roughly your latitude and facing the equator (south in the northern hemisphere). Reuse the salvaged rails on a simple wooden frame.
• Wire it panel → charge controller → battery → load. Never connect a panel straight to a battery. Match the panel's Voc to your controller's maximum input voltage — an MPPT controller is preferred.
• Pair with Solar Power Systems for wiring and sizing, Battery Maintenance for storage, and the Off-Grid Power Calculator to balance the system.

9. Faraday Cages & EMP Protection

What is an EMP?

An Electromagnetic Pulse (EMP) can come from: a nuclear detonation at high altitude (E1, E2, E3 pulses), a solar coronal mass ejection (CME/solar storm — primarily affects power grid infrastructure), or an EMP weapon. The threat depends on proximity, shielding, and whether electronics are connected to power lines (which act as antennas, amplifying damage dramatically).

What a Faraday Cage Does

A conductive enclosure attenuates electromagnetic fields by redistributing surface charges. Electronics inside that are not connected to external conductors (power lines, antennas) are protected from field induction.

Building an Effective Faraday Cage

1. Simple option — galvanized metal trash can: Heavy gauge galvanized steel trash can with a tight-fitting lid. Wrap contents in bubble wrap or cardboard first (insulate from the can walls). The lid-to-body gap is the weak point — wrap with metallic tape or aluminum foil.
2. Better option — nested: Wrap each device in a layer of mylar bags or aluminum foil (non-conductive padding between device and foil). Place into an anti-static bag. Place anti-static bag into a galvanized metal box. Place metal box inside a larger cage. Each layer adds 20–30dB of attenuation.
3. Room-sized cage: Line walls, floor, and ceiling with copper or aluminum mesh (hardware cloth with mesh <1cm). Overlap seams 10cm and connect with metallic tape. Door: overlap edge of door with conductive gasket. Ground the cage for best performance in lightning/E3 events.

What to Protect

• Handheld ham/FRS radios (Baofeng, etc.)
• Charge controllers and inverters (critical for power system recovery)
• A laptop or tablet with offline data/this guide
• Spare solar charge controller and MPPT
• Medical devices (insulin pumps, CPAP)
• Vehicle electronics (keep a carbureted vehicle or older diesel as backup)
• Spare ignition modules for vehicles
• LED flashlights and headlamps (simple ones are naturally EMP-resistant)

10. Fuel Storage Safety

Gasoline

• Shelf life: Untreated gasoline: 3–6 months. With fuel stabilizer (STA-BIL): 12–24 months. Store in UL-listed, red fuel containers.
• Stabilizer: Add at ratio specified on product (typically 1 oz per 2.5 gallons). Mix thoroughly. Best added to fresh fuel at point of purchase.
• Storage: In a detached outbuilding or shed, not attached to or inside the house. Cool, dark location. Away from ignition sources (water heaters, furnaces). Good ventilation — gasoline vapors are heavier than air and accumulate at floor level.
• Maximum quantities: Many fire codes limit residential storage to 25 gallons (94L). Know your local regulations.
• Rotation: First-in, first-out. Use old fuel in lawn equipment, rotate with fresh. Never store "indefinitely" — degraded gasoline gums up carburetors and injectors.
• Ethanol-blended fuel (E10): Absorbs water and phase-separates faster. Use ethanol-free fuel for long-term storage or 2-stroke engines. Store ethanol fuel only with stabilizer.

Propane

• Propane stores indefinitely if container is in good condition. No stabilizer needed.
• Store cylinders upright in well-ventilated outdoor area away from heat sources (>120°F/49°C). Do not store in enclosed spaces — leaks accumulate at floor level (propane is heavier than air).
• Inspect cylinders for rust, dents, and valve condition annually. Have cylinders inspected before refilling if any damage is present.
• Portable 1-lb cylinders: do not refill unless you have a proper refilling adapter and scale — overfilling is dangerous.

Diesel

• Shelf life: Treated diesel: 12–24 months. Biodiesel blends degrade faster (6–12 months).
• Store in blue containers (diesel standard) or clearly labeled drums.
• Diesel is less explosive than gasoline (higher flash point) but still a significant fire risk.
• Algae growth: add biocide (Biobor JF) at storage to prevent microbial growth in long-term stored diesel. Filter before use if stored >6 months.

Firewood

• Season hardwood for minimum 6–12 months before burning. Freshly cut wood is 40–60% moisture — it doesn't burn efficiently and produces excessive creosote.
• Stack off the ground on rails/pallets. Cover top but leave sides open for airflow.
• Store away from the house (insect and rodent harborage). Bring inside only what you'll burn that day.
• BTU comparison: Oak ≈ 29 million BTU/cord, Apple ≈ 27 million, Pine ≈ 17 million. Hardwoods are significantly more energy-dense.

11. Rocket Stoves

A rocket stove burns small-diameter wood (pencil to wrist thickness) with 80–90% efficiency compared to 10–20% for an open campfire. It uses an L-shaped combustion chamber that creates a powerful natural draft, producing intense, clean heat with minimal smoke. After mastering the Faraday cage and solar panel, the rocket stove is the highest-impact energy build in a long-term survival scenario.

Why Rocket Stoves Matter

• Fuel reduction: Cook the same meal using 80–90% less wood than an open fire.
• Smoke reduction: High combustion temperature burns off most particulates — critical for indoor or semi-enclosed use.
• Fuel flexibility: Burns small diameter twigs, scrap wood, and biomass that open fires can't use efficiently.
• Build time: A functional brick rocket stove can be built in under 2 hours with basic materials.

Basic L-Shaped Combustion Principle

The key insight: the horizontal feed tube angles slightly downward at the L-junction, creating an air gap beneath the wood. Air is drawn through this gap, over the fuel, and into the vertical chimney — creating an intense, self-sustaining draft.

Brick Rocket Stove — Build Instructions

Materials: 16–24 standard bricks, clay or fireclay mortar (or mud mortar for temporary builds), a metal grate or two parallel metal bars, a metal cooking ring (optional).

1. Lay the base: two bricks side by side forming the floor of the horizontal feed tube. Leave a 5–8cm (2–3") gap between them — this is your air inlet.
2. Build up the sides of the feed tube 2 bricks high on each side, creating a channel ~15cm (6") wide and 30cm (12") long.
3. At the back of the feed tube, build the vertical chimney straight up: 3–4 bricks high. The interior channel should be the same width as the feed tube.
4. At the L-junction, place a small metal grate or two parallel rods to support wood above the air gap.
5. Cap the top with two bricks or a metal ring leaving a gap for the pot to sit close over the flame without sealing it. A 2–4cm (1") gap around the pot rim is ideal.
6. Mortar all joints with clay or fireclay. Allow to cure and dry for 24 hours before first use. First fires should be small while the mortar cures.

Operating Tips

• Feed wood horizontally from the front. Push it in slowly — the fire should stay at the L-junction, not in the feed tube.
• Use dry, split wood. Wet or large-diameter wood dramatically reduces efficiency.
• Position the pot to cover most (but not all) of the chimney opening — this concentrates heat on the bottom while allowing gases to escape.
• A properly operating rocket stove produces very little smoke. Heavy smoke means wet wood, poor air supply, or insufficient draft height.

12. Solar Cookers

A solar cooker uses concentrated or reflected sunlight to cook food with zero fuel. A well-designed solar box cooker reaches 120–150°C (250–300°F) — sufficient to cook, boil water, bake bread, and pasteurize water. A parabolic solar cooker reaches 250–400°C (480–750°F) — frying and boiling in minutes. Both can be built from salvaged materials in a few hours.

Box Solar Cooker

Best for: Slow cooking, baking, pasteurizing water, low-supervision cooking. Less fire risk. Can be left unattended.

Reaches: 120–150°C (250–300°F) in full sun.

Build

1. Make two nested boxes — inner box slightly smaller than outer. The gap between them (4–8cm) is filled with insulation: crumpled newspaper, dried grass, wool scraps, or straw.
2. Line the interior of the inner box with aluminum foil, glued shiny side up.
3. Paint the cooking pot flat black (absorbs maximum heat).
4. Cover the top with a sheet of glass or clear plastic stretched tight. This creates the greenhouse effect — lets light in, traps heat.
5. Make a reflective flap from cardboard + foil, hinged to the back of the box. Angle it to direct additional sunlight into the box opening.
6. Orient the box toward the sun. Check and reorient every 30–45 minutes for optimal cooking.

Parabolic Solar Cooker

Best for: Fast boiling, frying, quick cooking. Requires supervision and frequent repositioning. Do not leave unattended — temperatures can ignite dry material.

Reaches: 250–400°C (480–750°F) at the focal point.

1. Make a parabolic dish from cardboard covered with foil, a satellite dish lined with mirrors or foil, or shaped aluminum sheeting. The dish should be at least 60cm (24") in diameter for useful cooking power.
2. Identify or calculate the focal point — where all reflected sunlight converges. For a parabolic dish, the focal point is approximately at the center of curvature.
3. Mount a cooking stand or arm to hold the pot at the focal point. Use a dark, thin-walled metal pot or pan for fastest heat transfer.
4. Point the dish directly at the sun. A 1-liter pot of water can boil in 20–30 minutes in good sun with a well-built dish.
5. Reposition every 10–15 minutes as the sun moves. Use long-handled pots or gloves — the focal point is genuinely dangerous to look at or touch.

Water Pasteurization Indicator (WAPI)

You don't need to boil water to make it safe — pasteurization at 65°C (149°F) kills all pathogens. A WAPI is a small tube with wax that melts at 68°C — when the wax has melted and pooled at the bottom, water is safe. Make one from a small plastic tube with a bead of wax sealed inside. Place it in the solar cooker pot — far less fuel required than boiling.

13. Biogas from Organic Waste

Biogas (methane + CO₂) is produced by bacteria digesting organic matter in the absence of oxygen. Animal manure, kitchen scraps, and crop waste can power a cooking stove or lamp continuously when set up in a digester. A well-loaded household digester can supply 2–4 hours of cooking gas per day from the waste of 3–4 large animals or 8–10 people.

Fixed-Dome Digester (Low-Tech)

Basic Floating-Drum Digester (Easiest Build)

Use a large buried container (500–2,000L) as the digestion tank and a smaller inverted drum or barrel floating in it to collect gas. As gas accumulates, the drum rises; as it's used, the drum falls.

1. Bury a large container (concrete tank, plastic tank, or lined pit) — minimum 1,000L for reliable output. Must be completely airtight except for inlet and outlet pipes.
2. Feed pipe enters the tank at bottom. Outlet overflow pipe exits at the same level to create hydraulic displacement (fresh slurry in pushes digested slurry out).
3. Place an inverted 200L drum over the gas collection opening. Weight it so it floats but stays centered. Connect a gas pipe from the drum's highest point to your stove.
4. Load the digester: 1 part fresh manure : 1 part water by volume. Ideal temperature is 35°C (95°F) — warmer = faster digestion. Below 15°C, digestion nearly stops.
5. Allow 2–4 weeks for initial bacterial population to establish. First gas produced will contain high CO₂ — purge it before using (light and let it burn off, or vent).
6. Daily loading: add fresh slurry each day equal to approximately 5% of tank volume. Feed consistently — irregular loading disrupts bacterial balance.

Feedstock Guide

The spent slurry from a biogas digester is an excellent fertilizer — pathogen-reduced and nutrient-rich. Apply directly to garden beds or compost. This closes the nutrient loop: waste → gas → fertilizer → food → waste.