Accidentally left one of the reading (dome) lights on overnight. Now car won’t switch into EV mode

So recently I had put in a new 12v battery because the one in the car reached the end of it’s life. Two weeks ago is when that happened.

Everything was OK until this morning. One of the reading lights out of four was accidentally bumped and left on overnight. The car had enough power to boot up the system and run the A/C and all that.

However, the car would not switch into EV mode with a warning that the battery was low. The bar graph meter shows the EV battery (I call it a traction battery) had almost all bars full. The car moves without the ICE being engaged so I know the motor is getting juice enough to move the car.

The amount of miles that shows up below the battery bar graph isn’t displaying. Could it be a computer glitch? Do I need to put the new 12v battery on a charge because of my mistake with the light? The light stays on even when the car is OFF, and I’m not sure if it times out or just stays on.

Or do I have larger problems afoot with the EV system, traction battery or computer? It’s only got 132,000 miles on it. For some cars that might be a lot, but I understand Prius’s to be fairly well made.

Any advice you can give will be appreciated. I know enough NOT to go messing around the high voltage system that has between 360 and 390vdc and enough amps to be fatal if you mess up.

 

My next step after topping off the 12v battery is to charge the traction EV system for a while, too.

 

Thank you for your reply.

On a 120V circuit, 15-20A, how long should it take for this older (it’s the original EV battery that came with the car when I bought it used in 2016) EV battery to come to a full charge on a Level 1 charger? After three hours the car had between 3 and 4 miles EV range, and the charging had shut off. I’ve never used the level 1 charger that came with the car before now because I didn’t have access to anywhere to plug it in where I live and not have it ripped off (aka stolen), until now.

I’m an apartment dweller, and just rented a single bay private garage from my apt complex with automatic garage door. Only place I have access to any electricity to charge the car.

What could possibly drain the EV battery to the point where the car thinks it’s totally discharged (but had enough power to move the car without the ICE, just no range appearing on the display)? It had between 8 and 9 miles estimated range when parked for the night.

The car was OFF when I went to use it the next morning, and had three fourths a tank of gas so the ICE wasn’t kicking on to compensate for a drained EV as if the car was in Ready mode (aka forgetting to turn the car OFF).

Charging: It’s seems to have. I charged up the 12V battery, then reconnected it and charged the EV battery for a few hours. After putting charges to both batteries, I had about 3-4 miles EV range as calculated by the Prius software in the car.

I also just bought an OBD2 tester and have the Dr. Prius app on my iPhone, so I’ll be checking out the car later.

 

Discovered why the charger shut off after a short time. Nothing to do with the car or charger.

 

Thank you. I did check the battery health using a bluetooth OBDII and Dr. Prius app and it also confirmed the battery health is fine. Thank you for your replies.