The battery is around 3-4 years old. I did notice it would be slow to tick over after filling with gas on a long journey a few weeks ago, where there was the aircon, headlights and dashcam all running.
This morning from out of nowhere it conked out and wouldn't turn over. Though the electric windows and and aircon would still run, and the dash would light up as normal, so didn't seem like a battery issue.
Got a new battery put in. See photo.
It turned over perfectly. On my way.
500 meters to 1 km later, the exact same thing.
It would turn-over sometimes, but loose power and cut-out quickly. While ticking over the engine did seem to be knocky, with a knocking sound that was audible. Go to move and it would cut out again.
Got a tow truck back to the house.
Turned her over no problem. Backed he into the driveway. Turns over and runs perfectly in neutral. 1st gear and reverse in the driveway is fine, no warning lights come on or came on.
I don't really fancy taking her out again to make sure, in case she cuts out, which loses the power steering and braking ability, so is quite dangerous on the road.
To the more mechanical minded and experienced, do the symptoms sound like a battery issue, or something else? The car is 9 years old with 80,000km, always serviced and never had any problems before.