Just finished my first ebike build. It went pretty smoothly. Only hiccup was that I had to ream out the center of the bottom bracket a bit to get it to push through. Getting wiring to look clean is a challenge but ended up alright. My 2022 Trek Marlin is a size M/L (18.5”) and the 20ah triangle battery fits perfectly in the front triangle and helps hide the wires.
I am a long time cat 1 Mtb and gravel racer and bottle cage mounts can’t even hold a water bottle tight over rough terrain, so I was not going to trust them to hold a heavy battery. That is why I chose a triangle battery with Velcro on 3 sides to make sure the battery stayed in place. I built my bike to be mostly on mountain bike trails. It will be a work bike hauling a bob trailer with a chain saw and trails tools. So far it has been great
That looks great and the battery is perfect for that space. I have a 25ah battery attached to the drink thingies and it is really heavy and moves a bit. What spacers did you need to clear the chainstay?