We have to leave an Arduino uno and a datalogger shield while running a DHT11 sensor for 24 hours? Would it be possible for 6 AA to power it for this long?
You need to simply measure the current drawn from the 6AA battery pack. Use a typical multimeter.
Divide the Ma/H rating of the AA batteries to find the number of hours it will run...
Other: IF the power supply, like the switchMode supply on the YourDuino RoboRED, draws less current from the 6AA's than the Arduino draws, you will get more time... For that kind of possibility see THIS page.. (https://arduinoinfo.mywikis.net/wiki/YourDuino-RoboRED)
Try it and see. Or, measure the average current draw and divide that into the battery capacity.
If you want a similar setup to run for years on a couple of AA batteries, study this excellent low power tutorial (https://www.gammon.com.au/power).
You could have asked this in your other thread.
An Uno draws about 50mA.
You need a 24H * 0.05A = 1.2AHr battery (with the right voltage) to power the Uno.
A DHT11 sensor might draw 0.3mA, so almost nothing.
AA batteries are likely about 2Ahr, so six connected to V-in should be able to power the Uno+DHT for 24 hours.
No info about your data logger. An SD card might be power-hungry.
A pack of 3xAA cells (4.5v) connected to the 5v pin will probably last just as long as there won't be any energy wasted by the voltage regulator.
True. Not sure what the "datalogger shield" expects though.