I’ve personally tested this new feature for our FT 817.
It is a kit that fit into your original case a LIPO 3000 mAh battery.

Lipo battery are widely used now by R/C enthusiast because of their high power to weight ratio as well as their ability to provide high current coupled with a flat discharge voltage curve. 

The WLB-817 kit replaces your FT-817 factory supplied battery tray and the custom made Charging Hatch replaces you battery door. The Charging Hatch features a an ON/OFF switch that cuts the battery off from the radio during charging or storage. The charger features a bi-color LED that indicates charge status.

Specifications

Operating VoltageCharged 12.6V Nominal 11.6V 
Charger100-240VAC Input 12.8VDC Output
Minimum Voltage9V
Charge Time4 Hours
Discharge Current2.5A Max
Charging Specs12.6V @ 1.2A 

 

WLB-817 Basic Kit Includes LiPo Battery, Charger and Hatch         $75 

 

http://www.hamsource.com/WLB-817.html

Video of the installation

 

73 de IZ0JOJ