wvmarle:
No idea how much power your display uses; just measure it. Keeping the backlight off wills ave a lot of power as well. The data sheet mentions sleep modes (I was talking about the processor itself), so that should be able to save some more.
I'd measure it, but I'm still in the planning phase, looking for the best solution.
ChrisTenone:
Can yuo show us a link to the LCD modules you plan on using? I suspect the 328 it's talking about is built into the device, and that it communicates with your Arduino by some other means, such as serial or I2C. If so, you won't need to worry about the internals of the device at all.
Sure. 2.8" TFT LCD Display Touch Panel SPI Serial 240*320 ILI9341 5V/3.3V STM32