For every hour of driving with "Crash detection" turned on, one’s phone battery will drain by approximately 2%, unless the device is being charged while driving.
In order for "Crash detection" to effectively detect a crash, one of the criteria to be met is that the user's device must have a battery level of at least 20%. Learn more here.
If you would like to conserve battery while driving, you can turn off crash detection by visiting your Safety Page and toggling "Crash detection" off. Please note that when crash detection is toggled off, none of its functionality will work in the event of a crash.