If this is a light to leave in the car for emergencies, then standby drain is an important criteria. Make sure that the X3 has very low standby drain, or you can lock it out easily.
Have you considered a 2xAA clicky for the car? No standby drain, decent output and run time, and it fits more easily in a glove box. (I’m not aware of any 3xAA or 4xAA clickies, but maybe there are some.)
Actually X3 has mechanical switch so there is no stand by current.
2 x AA are compact but 3x and 4x has more lumens and better candel standing.
Thrunite TN4A is also good option but I miss 20% Cristmas discount.
Flashlight for leave in the car, came to my mind
Oopsss, it is hard to find
http://www.illumn.com/starry-light-sa-22-880-lumens-4-x-aa.html
I have the Convoy x3 and haven’t had any issues with the battery carrier that came with it, have only been using aa’s. It won’t stay on high for more than a few minutes though before the voltage drops with aa’s and it starts flashing, as was mentioned above, can’t sustain the draw.