what happens

[loonyboy30]

what happens if you try and use a 6 cell battery when a 7 cell came with the heli.

[tdswan]

You won't haved as much power at the least, at the most the electronics and gyro and such won't have enough power to function.

[SSG Scott]

It runs slower. You can try it as it wont hurt anything.

-Scott

[kiwipilot]

What is the difference in overall voltage?

Personally I would recommend using a similar or better battery than came originally with your heli.