Working on these electric bikes has involved a lot of soldering. All I had originally, was a rather feeble 30w soldering iron that I've had for 50 years, and a roll of solder inherited from my father, 60 years ago.
I've now equipped myself properly.
As well as the old 30w iron, I have a 60 watt iron and a 100 watt. I also got a soldering gun, but that's stopped working a week after it arrived and I'm aiming to get a replacement from the vendor.
I also got some spare bits, a couple of spare elements (I've used one of them to repair an old 60 watt iron), a tub of flux, cleaner sponges, and a copper shavings ball tip cleaner. A roll of solder, 100 grams, 1.2 mm thick, and another 0.8 mm.