Voltage from the charger must not exceed the specified battery voltage by more than ~ 10-15% .
The electrical components on the circuit boards were specifically designed for a certain voltage range. Going under that is bad....going over that is bad.
The wattage is the power supplied.....voltage is different.
Higher amperage is ok for a fast charge but you still want the correct voltage.
The voltage of the Inspire battery is 22 volts DC - 22v * 15% = 3.3v (so it needs a 25 - 26v charger)
The voltage for the Phantom battery is 15.2 volts DC - 15v * 15% = 2.25v (so it needs a 17 - 18v charger)
You CAN use a higher WATT charger (more current available), but not higher or lower voltage.
Note: Slow charging a battery usually extends the life of the battery. While the 100 Watt charger will definitely charge the batter faster, it will generate more heat in doing so. Heat kills batteries. Better to have more batteries and charge them at 57 Watts than one and charge it at 100 Watts.
That's why this charger outputs more voltage. You don't charge a 12v car battery with a 20v charger.
The charging voltage should only exceed the rated voltage by about 10-15%
While it "might" charge the battery, it will be over voltage and will damage the battery (if it charges at all due to the intelligent circuitry)
Do not buy this charger for the Phantom 3 (is my best advice)