When the power goes out

Now, while the power is on: five minutes

• Open PowerBench and count your station with your own appliances (below: how).
• Install PowerBench, ToolBench, TimeBench and PassBench on the phone as apps: each one has its own icon (how, on every platform: a separate post).
• In ToolBench, on the Sun & moon tab, choose your place once: it is remembered.
• Charge everything that charges. Including the power bank you forgot about in a drawer.

1PowerBench: how long the station lasts

The sticker on the box says 1024 Wh. The box is optimistic. PowerBench counts what you will really get: on the Appliances tab you list what will run (fridge, router, gas boiler, lamps; any number can be changed), and How long it lasts answers in hours, with the station’s chemistry, the depth of discharge, a reserve for ageing, the cold and the inverter’s losses.

The default numbers make a nice lesson in modesty. A LiFePO4 station of 1024 Wh with the Typical set of eight appliances (a fridge, a router, a laptop, two phones, four LED lamps, a TV, the gas boiler’s electronics and its circulation pump) lasts 3.8 hours. Leave only the router, the phones and the lamps, and it is 19.4 hours. Add the fridge back, about 9.3.

• The inverter eats too. Its Own consumption is 15 W by default, as much as the router. With small loads that is a third of everything. If the router and the phones can run from the station’s USB or 12 V outputs with the sockets off, put 0 there to see how much you win.
• Cold takes its share. The same router and lamps at 0 °C: 16.7 hours instead of 19.4. A station on a cold balcony is a smaller station.
• Which to buy works the other way round: for eight hours of the typical set with a 20% margin you need about 2,600 Wh, a Large station.
• Charging and the Outage schedule show whether the station refills in the hours with power. From a 600 W mains input, that 1024 Wh refills in about 1.9 hours.

Under every tab, How it is calculated shows the formula with your numbers. Save to history keeps the calculation in the browser, and a link keeps it in a message. The page says it right in its header: Works offline, nothing is sent.

2What works without the internet

When fof.lol is opened for the first time, the browser saves every page of both languages and the tools’ own files. After that, a page opens without a network, and a tool that needs nothing from outside simply works. PowerBench is one of them, and so are the three below. Honestly, not everything does: SpeedBench has nothing to measure without a network, WhereBench shows coordinates but no map, and DropBench has no one to pass a file to.

3ToolBench: the sunset and the neighbours

ToolBench counts the sun and the moon by formulas, right on the phone. The Sun & moon tab gives the sunset, civil twilight and the length of the day: exactly how long you have before the candles. It is calculated for the place you chose, so choose it in advance.

The Compass, the Level and the Protractor read the phone’s own sensors and need no network either. And the Sound meter will tell you in dB(A) how loud the neighbour’s generator is. It will not make it quieter, but now you have a number.

4TimeBench: a timer in the dark

The Timer and the Stopwatch in TimeBench work without the internet: to switch the station off the charger, take the pot off the camping stove or remember when the generator was started. Quick buttons: 1, 3, 5, 10, 15, 25 minutes and an hour. The signal is scheduled in advance, so it sounds even when the tab is in the background.

Two honest notes. While the timer runs, the screen stays on, and in a blackout that costs battery: dim it. And the Exact time check needs the internet; without it the page shows the phone’s own clock and says so.

5PassBench: a password by candlelight

The router now lives on the station, and the neighbours are already asking for the Wi-Fi password. PassBench makes a new one without the internet: random numbers come from the phone itself, and the word list for a Passphrase is part of the site. A few plain words are easy to dictate in the dark and hard to guess.

Offline, two things don’t work: the dictionary check (the page warns that the estimate may then be too optimistic) and the leak check. Both can wait for the light.

6Install it in advance

The most useful advice in this post is the most boring one: do it today. Opening fof.lol once is enough for the pages to be saved, but an app on the home screen is more reliable. It opens with one tap, and Safari on an iPhone may clear the data of a site you have not visited for a while, while an app on the home screen keeps it. Open each tool once while online, and allow the sensors where it asks.

How to install on Android, iPhone, iPad and a computer: a separate post. In the dark, the install button is just a button.

Safety: what no calculator replaces

• A generator only outdoors. The exhaust has carbon monoxide: no smell, no colour. Never in a flat, on a balcony, in a garage or under windows.
• A gas boiler needs a pure sine. A cheap “modified sine” UPS can burn its board or the pump.
• Don’t charge LiFePO4 below 0 °C. A station from a cold car or balcony warms up indoors first.
• Never back-feed the house wiring with a plug-to-plug cable: it is dangerous for the electricians on the line and for your neighbours’ appliances.
• Medical equipment: plan for twice the outage and keep a second source.

The full list, with the items that apply to your calculation highlighted, is in the Safety block of PowerBench.