More curious than anything, this has really got me scratching my head... Wondering if anyone can explain this mystery to me?

10 months ago, I accidentally left a pump (for bike tyres) plugged into the 12v socket overnight. The next morning, battery flat, I took advantage of my free breakdown cover and called assistance to jump start. Ran it for 30 minutes, switched engine off. The next day, battery flat once more. Enrolled the assistance of a neighbour to give it a jump start. Off I go to work. I realise my stereo no longer works (won’t switch on, clock / temp / date still on dash, but besides that not responding, nothing, nada). Check fuses, all looks ok. I nip to my KIA dealership on the way home, suspect the stereo maybe needs a code. The service department had never heard of this concept (thought this was common place!), perhaps a fuse has blown elsewhere and they can’t get to it, suggest the car goes for diagnostics, “how much will it cost” “how long is a piece of string?” Helpful. I decline, I can live without a stereo for now, it doesn't sit right with me that it isn't working and I want to read more.

Three months later, having left the car sitting for a few days on the drive, the battery is dead again. This repeats, again in three months, then in a month, then six weeks, then two weeks, then - this week - 3 days.

I discover the batter is the same since manufacturing, 8 years old, it's had a good innings, repeatedly jump starting will have done no favours, time for a replacement. I order my new battery online. Change the battery - starts - Great! Let’s take it for a decent run, 40 minutes. On the off chance I try the stereo. It switches on, no bother.

So strange... did that initial jump knacker the battery? Will test the alternator tomorrow. Fingers cross it was just the battery...

Cars! Who’d have ‘em??