The GS-911 manual states to connect an intelligent batter charger for service functions. I had an OptiMate 4 connected, which did not help.
the clever ones are NOT very helpful when it comes to providing the grunt when you know its required - they are so clever they sit analysing stuff for many minutes till its too late... and then if lucky they cut in to charge mode and pretend to do a slow recovery charge... when you know the bike needs 6 amps NOW !
I bought a cheap one and throw it on car winter full grunt mode WHENEVER THE KEY IS ON - trouble is they are so dim - a KEY OFF cycle as requested at times, trips it back to sleep - if you aren't on the case - you miss it
chargers without any display are just an utter fiasco I haven't tried on a bike but now have a snap-on one thats grown up enough to do its job properly but they are $1600 - the link is the old 2022 model, latest one now gets LiPo support
https://public.snapon.com/UserManuals/ShopTechTools/EEBC500INT-00-99-000963-1109.pdf
Flash reprogramming Power SupplyProvides a consistent power at the OEM specified voltage (user entered) to allow for uninterrupted flash reprogramming of vehicle’s computers or to retain vehicle system settings
When reprogramming, the power supplied to the vehicle module must not drop below OEM specified voltage. Some reprogramming operations with the key-on will turn on cooling fans, fuel pumps, and other components that will cause the battery to drain faster than normal. Instead of pulling fuses to prevent the battery drain, it is easier and more practical to have the vehicle connected to a constant voltage power supply. During reprogramming, there is a risk of having the operation fail if the voltage falls below the proper operating voltage. Sometimes a failed operation can be recovered, but there is a chance that failed reprogramming could ruin the control module