4 weeks ago I changed a 12V battery on my Toyota Prius auto. But after being in for two weeks the battery was discharged again. I tried to recharge it, but it did not work - the charger does not start charging - though the battery voltage was 0.1 V. Now I want somehow to start the car and go to the service and check the electronics. To do this, I have bought a new battery.
What should I do with the first battery? Is it possible to recover it or not? Has anyone encountered such a strong discharge in a relatively short period of time? Does this mean the battery status?
How should I prepare a new battery: are they sold already charged or is a pre-charge needed before installation?