Power source for car-robot

Hello everyone,

I am building a car-robot on arduino with 4 motors driven by 2 drivers l298n.
Robot perfectly works with DC power supply, but does not want to move if battaries are in use.
It consumes current around 0.35A, and the voltage is 9V-12V.
I have tried 9V ultra lithium battery - did not move. 8 AAA alkaline batteries(~12.5V) also cannot make it work.
Would it work with 8 AAA Ni-MH or Li-Ion batteries?
Could you please recommend me some 9V-12V source which can provide enough output current for this robot?
Thanks in advance...

Measure your power voltage, I think it may be drooping causing problems. You are not stating what the power supply is so I assume it is 12V. Consider using a SEPIC converter to power your unit form the batteries. This response is to help you get started in solving your problem, not solve it for you.
Good Luck & Have Fun!
Gil

Thanks for the answer!