Battery dies after I drive my daughter’s prius

If the battery is over 5 years old and the car is not driven often, it's just a coincidence you get the surprise dead battery.

After the dead battery episode, I would assume you just jump start it and go about your day again? Leaving the battery at a very low state of charge for the dead battery episode to repeat itself when you get in it the next time.

If the battery is over 5 years old, change it out and you shouldn't have this problem again. Surely you were the main driver of this car before your teen got it, so you know how to operate it properly.

 

perhaps she is driving it further and it has time to charge a bit

 

There should be a date on the battery, my guess that battery is quite old. After a while, they just don't hold a charge for long, even after you charge it.

 

didyou get the covid vaccine, you might be magnetized

 

The only thing I can think of is a loose wire that your bigger feet are brushing (under the dash) or that your heavier butt is disturbing (in the seat).

 

No surprise the 12 volt battery is shot. One good deep discharge and will never be the same. You keep propping it up with charges.
Remedial charges only helps a healthy battery.

Everyone comes on here scratching there heads about the 12 volt battery,
One voltage check at the front jumppoint will tell you what’s what.

Healthy 12 volt battery lives at around 12.6 volts at the front jump point.
A healthy 12 volt battery will not drop more than .5 volts with car off and headlights on and high beam. Your battery will fail both those tests.

 

maybe the extra weight in the car causes fatigue

 

My experience, each time I've replaced the 12v battery, is I've literally said "I always forget how much better everything works in the Prius with a 12v battery that's never had to be charged" to my SO. She reminds me of it when I do it.

If a Gen 2 12v needs charging, it needs replacing. I always wait and screw around charging it a bunch of times for a year or so...but I *always* recognize other things were affected too after the new battery is in.

The car is telling you every time you get in. It's not telling her, it's telling you!

 

First, is there an 'automatic' on the Gen 2? I thought it was merely on/off with auto off when they're left in the on position. I'll have to look, lol. anyway.....

It could also be the order in which you exit the car/turn off the car while headlights are on.
Do you open the driver door before or after you turn the car off?

If I remember correctly:

1. if you turn off the car first, then open the door, the car assumes you are finished with the car and it turns lights off.
2. if you open the door, then turn off the car, it assumes you want to leave the lights on, so it leaves them on.

 

If you have to charge a battery on a car that is regularly driven, then it REALLY needs to be replaced.

FIRST thing I would do is replace the aux (12v) battery, especially if your kid drives alone a lot.

I don't KNOW whether or not G2s have automatic lights, and since I do not know I would suggest turning them off after you use the car.
Make sure that you're closing the doors all the way, not leaving the interior lights on, or any aftermarket electronics energized.

All the usual suspects.

 

To some regularly driven means going to the store 1 mile away and back and that’s it.
Like many people here with bad 12s.

Regular maintenance charges are a very good thing to do if you pay attention. See how long it takes the fully charged light to come on and note it.
At the 3 year mark my yellowtop took forever to fully charge and is now on my sh*t list as my last yellowtop died fast at the 3 year mark.

no more yellowtop for me. But if I did not test it I would never know.