MarkT:
The Arduino has an on-board regulator, supply 11V to the barrel plug.A lithium battery will not have any difficulty sourcing enough current
for small motors - in fact you might want to consider adding an inline fuse.With 11V to the Arduino there is 6V to be dropped by the regulator so
it may get quite hot - if the other 5V peripherals draw a lot of current
you may need a separate 7805 regulator on a heatsink (or a DC-DC
converter).You don't mention a motor controller - are you using one? What
voltage are the motors?
I understand now why it is suggested. Thanks. As you stated arduino may get hot because of power supply voltage(measured Li-Po voltage when fully charged is 12.6V ). Then we shold use 7805 for arduino since our board is not genuine. I may get crazy with 12.6V XD
We are using a motor driver for DC motors with 12V supply.
The LiPo battery has C 25 rating (25*1.45= 36.25 A) I think we do not need regulator,do we?