Friends
I use 8 no of 1.2 w rechargable cell for my Tx, If I want to use lipo in my tx which lopo should i use 2 cell or 3 cell?

3-cell should work.

Which TX are you using?

I use 2s 500-1300mah 20C+ to power Flysky 9ch Tx, because Tx(regulators) accept anything between 7-12VDC and think circuit voltage is 5V. Ideally low discharge(C) batteries are preferred, but you can use batteries with higher discharge rates they can be fit inside the battery compartment.