I’m sorry but I do have the 2.5 version and I do not have. Powertank. I posted here because I thought it had to do with why it was no luck Negri charged my bike but now it seems to be more than that.
Charging fuse(s) are logically as fast blow fuses (values vary by model and year, say 50A? 100A?) inline with the bike wiring harness well protected in heatshrink and would be difficult to access directly. Replaceable with mail order parts however just a bit of a pig to service.
What you should measure to see if the AUX fuse is intact is bike main voltage on the aux connector anytime the ZForce pack contactor is engaged (bike on, wait for click). This can be done with any voltmeter and some care with your hands to avoid a high voltage shock.
If the charge fuse popped then it's probably easier and cheaper to build your own secondary fused charging harness for connection to the motor controller terminals. Otherwise if charge enable signal was damaged to/at MBB then you can still get energy into the battery, the bike will have to stay on and not timeout while charging, which is an issue that some owners have encountered - annoying and difficult to fully remedy but can still make the bike usable again.