Energy and power

Small electrical systems, safely, and the fires they start when done wrong.

• EP1 Size and wire a 12V solar systemWorking out what you actually need, in the right order: loads first, then battery, then panel, then controller, then wire and fuses. Most failed systems were sized off a guess about the panel instead of a measurement of the load.Quick actions, 9 steps
• EP2 Charge and store a LiFePO4 bank safelyThe one rule that matters most is that you must never charge these below freezing, because the damage is permanent, invisible and happens on the first cold morning. Everything else is settings and storage habits.Quick actions, 7 steps
• EP3 Run a generator without killing anyoneThe distance figure most people carry is too short, and the tests that established that were done in calm air. Plus the three other ways generators kill: refuelling hot, backfeeding the house wiring, and being run in the rain.Quick actions, 7 steps
• EP4 Build a solar dryer, and angle it for the seasonThe tilt arithmetic is the same for a dryer, a solar oven and a solar panel, so learn it once. Then the honest bit: in Britain the limiting factor on solar drying is humidity, not sunshine, and a design that ignores that will mould your food.Quick actions, 9 steps
• EP5 Site, test and replace smoke and CO alarmsWhere they go, how often to test them, and the fact almost nobody knows: alarms expire. A ten year old smoke alarm with a good battery and a working test button may still not detect a fire.Quick actions, 9 steps
• EP6 12V wiring safety, fuses and crimpsLow voltage feels safe and is not. The fires come from three places: a fuse chosen for the appliance instead of the wire, a fuse that cannot interrupt what a lithium bank can deliver, and a bad connection quietly heating up for months.Quick actions, 9 steps
• EP7 Make candles and oil lamps from rendered fatTallow candles are soft, smell of what they came from, and were what most of Britain burned for centuries. Making them well is a matter of hardening the fat and matching the wick. The oil lamp is easier and gives more light per unit of fat.Quick actions, 9 steps
• EP8 Charge phones and small batteries without damaging themA bare solar panel is not a charger, and plugging a phone into one is how phones die. The buffer battery is the whole trick. Also the honest arithmetic on hand cranks, which produce far less than anyone expects.Quick actions, 9 steps
• EP9 Maintain a generator and store fuel legallyModern petrol goes off in months, not years, and the law limits how much you may keep. A generator that has sat untouched for two years will not start, and the reason is nearly always the carburettor rather than anything expensive.Quick actions, 9 steps