We've discovered a last minute HARDWARE BUG. It has been determined that the lithium battery charger on the Basic and Pro boards is incorrectly designed. You can still use the Basic or Pro to trickle charge a lithium battery, but there is no overvoltage protection or current limiting. The battery charger chip is bypassed entirely, and any battery charging occurs by connecting the lithium battery directly to the USB voltage via a current limiting fuse and diode.
In some cases, it may still be safe to charge a lithium battery if that battery has an overvoltage protection circuit and will not be damaged by a charge current of up to 500mA. When in doubt, use an external charger.
We apologize for the inconvenience. We know backers of the Pro boards were promised chargers, and at some point we started advertising the Basic as featuring a charger as well. We cannot repair the existing boards, but in the future we will offer a discount to affected backers when new boards are available.
For more information, please see: FlutterWireless.com/i/charger
This bug will be fixed in future manufacturing runs.