you can put solar panels to charge the LiPO 7.4 V Battery instead of LiPO Battery Balancer Charger.
Other robots from Synthiam community

Tmesserschmidt's Meet Melvis: My Ultra Humanoid Robot
Melvis (Sometimes called Stu) used to use several boards, but now I am just using the EZB for EVERYTHING! The robots...

Ezang's Simple Bot Car Robot
No frills or thrills - no sensors or lights - I am Simple Bot, I hope you enjoy the simple life sometimes, its good for...

Mcjeff0125's Robie Sr, Dr. Theopolis Hybrid
May I present to you my Robie Sr, EZ-Robot mod. As you can see, I did not use the stock Robie head. My main reason was...