I am having the same issue trying to find a replacement for my failed battery. (Bike won't charge or turn on.) I have to say that I got a quick response from Focus. Here it is.
Response for customers:
We have the JAM2 376Wh battery in stock in North America. You can purchase a Jam2 battery...
I have the Mudhugger long on my Jam2 Plus Pro and my Turbo Levo Expert 6fattie. I'm in the Seattle area and ride all year long. (no car)
By far the best option that I have found.
I have a 2017 Jam2 Plus Pro and a 2017 Turbo Levo Expert 6fattie. I call the Levo my Cadillac and the Jam2 my Jaguar for all the reasons those names imply. I have a T.E.C. pack for the Jam2 and an extra battery for the Levo. With that the Levo wins on range. Bikepacking with paniers, I chose...
Sounds like chain stretch. Probably happens on your higher gears, too.The things you will go through more on an E-bike, are chains and cassettes. Look for E-bike specific parts. They last longer.