Everything else in this section is about what happens to you on a road. This lesson is about what happens to a house at night, and none of the people it happens to are riding at the time.

We did not write any of what follows. It is the fire code body and the federal fire service, and where they overlap they say almost exactly the same thing. That is unusual enough that it is worth taking the whole list at face value.

Only the charger and battery that came with the machine. Never a substitute, never an extension lead, never a multi-plug adapter.

Unplug it when it is full. Not overnight, not left on for too long.

Never in a doorway or a hallway you would escape through, and away from anything that burns.

Not in extreme heat or cold, especially while charging.

And the fifth: if it does catch fire, do not try to put it out. Get everybody out, then call 911 from outside. A lithium battery fire is not a fire you fight with anything you have in the house, and it makes smoke that is the thing that actually hurts people.

A cutaway house with a hallway, a bedroom, a garage, a kitchen counter, a back step and a cabinet under the stairs. Drag the charging machine into a room, then choose wall socket or extension lead. The card lists which of the five rules you have just kept and which you have broken.

Try the room it charges in now, first. That is the one this lesson is actually about.

Stop using the battery if you see any one of these.

An unusual smell.

A change in color.

Too much heat.

A change in shape — swelling or bulging.

Leaking, or smoke.

It stops holding a charge.

The fire service also says to look for cracking, bulging or leaking as a routine thing rather than only when something feels wrong, which is why it went into your pre-ride check in the last lesson. One sign is enough. You do not need two, and you do not investigate it.

You do not carry it anywhere, you do not put it in a bucket, and you do not go back for the machine. Get people out, then call from outside, then do what they tell you.

Pick every one that is right, then press Check.

Find all 5.

A dead battery does not go in the trash can. Lithium cells are not household trash anywhere in either country. They go to a battery recycling point, or your local waste service will tell you where. A crushed cell in a bin truck is how some of these fires start.

And repairs are a qualified professional, always. That is written flat, with no exceptions in it. There is no part of a battery, a motor or the wiring that is a job for you, a friend, or a video. Everything else on this machine you can learn to do.

Check where the battery charges tonight.

Go and look at where your battery charges tonight. Its own charger, straight into a wall socket, not in a bedroom, not across the way out of the house, nothing burnable next to it. Move it if it is not, and tell whoever else lives there where it is now.