It is not rated for a 16000 mah battery. Its more then proper voltage and current that determines what a charger can do. Go back to the simple water hose analogy for electronics and current flow. Basically you are trying to put enough water to put out a house fire thru a garden hose. It simply ain't gonna happen with that gear. You can drop the charge rate down to .1 amps and MAYBE that wont tax the charger but other then that 16000 mah is way too large for normal charging on only 72w chargers.
PsyBorg, I don't believe the battery size matters when you go to charge. Cell count is the most important factor. If the charger is truly a constant current/constant voltage charger it should charge at the max current until maximum voltage is reached, then charge at maximum voltage until the current is zero. Battery capacity determines how much current the battery can safely handle to charge with.
That being said it can only charge at the current the device is rated for. This is different for each cell count, hence the "Wattage" of the charger. 72W sounds reasonable for this model of charger.
No matter if the battery is 300mah or 30,000mah a constant current load will treat the charger the same. Also, reading a voltage from the balance charger should not be effected by the capacity of the battery.
If it's a 72W charger, try setting the current to (72w/22v =) ~3 amps and see if that helps.
Is the charger a genuine b6 or a clone? I know a lot of cheap clones exist that have very questionable quality.
Source: Bachelor of Science in Computer and Electrical Engineering.