The simple charger (without electronics) delivers 11V while branched, but no current. In accordance with to this, the battery gains some volts, but does not appear to get capacity.
If the charger is branched, the main switch solenoid works and the avionics woke up.
If the engine is started with a car starter cable, the avionics work but show low voltage readings.
Is all this congruent with a completely dead battery?
The battery is a oddyssey AGM PC310 motorcycle battery. Stupid question: what would be appropriate replacement?. Regulator is the stock ducati. Similar capacity, same size, something else?