Folks,
I just got off the phone with the U.S. Product Manager for the Turbo line at Specialized HQ. I explained that battery availability is not just a warranty replacement issue for 24 months, but a long term support issue due to the proprietary nature of the battery system. I asked for a more formal statement about battery availability for the Turbo/Turbo X/Turbo S over the long term. I emphasized that this affects their ability to sell out their existing inventory since informed buyers are concerned about getting stuck with a piece of useless iron with zero residual value!
The "architecture" of the Turbo line creates an unfortunate characteristic in that all of the "smarts" for controlling the bike (not just battery management, but motor control, handlebar interface, bluetooth interface, etc.) is in the battery as opposed to the bike. The motor and handlebar controller are relatively dumb slaves to the battery. Thus if there is a battery failure, it is not just a matter of replacing cells, but also replacing the controller and bike settings, etc..
Newer systems like the Stromer ST2 have the "bike-specific smarts" embedded in the bike with a relatively dumb battery. Battery swaps do not affect the personality of the bike (features, odometer settings, etc.). The battery does have to deal with cell management and temp monitoring, but not much else. This makes batteries cheaper and potentially denser per watt and also makes the potential for 3rd party repack more likely. The Bosch and Brose also have relatively "dumb" batteries as well with control functions in the mid-drive, so that battery replacement should be more straightforward without having to have the dealer re-program anything using diagnostic programs.
By the way, the dealer diagnostics and cable for the Turbo line were never really designed for field support. The diagnostic interface is an obtuse "command line" set of code run from the "DOS" prompt on a Windows PC. Having worked with embedded microprocessors for years, it is obvious to me that this was designed as a software development tool that got thrown into the field without any real thought about how to deploy firmware fixes in the dealer chain or with the end-users.
So as soon as I get feedback from the Product Manager, I will try to respond with something more formal from Specialized.
Doug