I dont know if my thermostat has anything to do with it but a couple days ago i put a new 1of those in my car i noticed that my battery gauge was totally low so i just thought my cabels were loose.the car still started but souned crappy startin up, i checked and they wernt loose but when i got home my car totally died i gave my car a jump and it started and i drove it and it putterd and started to die out but made it home the sounds it made worried me so now its just dead.

 

Did you remember to hook all the wires back up to the alternator?
Charge the battery.
If it starts giving you issues again then have your alternator tested.

You're T-stat will not cause the problem.