What’s the voltage on the battery?
Is the alternator charging the battery?
A faulty alternator wouldn’t charge a battery while the engine is running, causing a flat/dead battery. Then when a new one is put in, it too is damaged or drained of voltage and is buggered as well.
Recharge the battery out of the vehicle and out of the sun.
If it’s still dead, it’s dead.
If it starts the car:
- Have the charge circuit checked.
- Have the battery load tested.
- Have battery health checked
Check for battery drain. That’s where a module or device in a circuit is remaining on and consuming power when it should be off. Without the car running, it’s going to drink that voltage from the battery like a free pint of cold beer on a hot day.
