If you suspect the charger is not effectively charging the device, place another object that charges wirelessly on the charger. You can use another Butterfly iQ, an iPhone 8 or newer, or another device that charges wirelessly. Reference the diagram below to understand charger behavior.
Note that the probe overlay in the image indicates how the Butterfly iQ should be placed on the charger.
If the charger does not charge another wireless device, then it is the source of the issue. Contact Butterfly Support for a replacement charger and include your shipping address in the message.
If the charger is able to charge other devices, it is possible the iQ probe is charging, but doesn't look like it is. Follow the instructions in the Resolving Charging Issues article.