Battery and alternator keep failing

Hello,

You could have a excessive parasitic draw (current drain) on the battery. Which can be draining it over time and making the battery go bad.
Every circuit with a battery will have little parasitic draw but it becomes excessive due to any electrical circuit (like a glove box light staying on or a shorted out window switch), it will drain the battery faster.

https://www.2carpros.com/articles/car-battery-dead-overnight

It can also be a wiring issue that preventing the alternator from properly charging the battery.
This can also be due to the control module for the charging system.

Just to clarify, the second time when this happened. Did the alternator tested bad on the vehicle or was the alternator tested out of the car?

If it got tested bad out of the car it could be just a bad alternator.

Please let me know of any questions.
Thank you.

To check for battery drain you will need to use a multimeter. With the key off check the amperage draw on the battery using the multimeter. Is the amp draw is higher than 50 milliamperage then it has excessive draw. To find out which circuit it causing the draw you will have to go through the fuse box and remove fuses to see which one has impact on the draw. If you were to remove fuse for a faulty circuit the draw will be lower.

Here is a good video that explains this:

https://youtu.be/z5F7WpgjaRs

Let me know of any questions.