One of the few failings of the K12 Nissan Micra is that the microswitch that opens the hatch develops a mind of its own and locks and unlocks frantically, thus draining your battery. You then have a second problem, charging the battery.
No problem. Take out battery, charge, replace.
Except that you have to get it out first by extracting the bolt right in the middle with the star sunk into it. You then find that you have a 12 and a 14 mm socket, but no 13 and you need an extension at least as long as the battery is high as well. Off to buy a cheap socket set then.
Having charged the battery, it’s common to find that the anti theft system no longer recognises the key and needs to be reprogrammed.
The joys of modern-ish cars.