Why does my Prius keep dying... am I doing something wrong

I’m really not good with cars at all. I can drive and do the basics, but when it comes to batteries and stuff, I’m clueless.

So, I got this Prius Hybrid as a donation, and it had been sitting for a while. The battery was completely dead. I got a jump start, and it fired up, so I drove it around for about an hour thinking that would charge it back up. But when I got home and turned it off, it was dead again. No lights, no locks, nothing.

I read somewhere that the 12-volt battery is in the trunk. Am I supposed to charge that one instead of looking under the hood? How do I do that? I’m scared to take it anywhere because if I park and turn it off, I might get stranded. I really don’t want to be stuck needing a jump start every time I go somewhere.

Any ideas on what I’m doing wrong?

If you’re in North America, here’s where the battery usually is:

  • 2001 to 2003 Prius: Left rear of the trunk.
  • 2004 to 2015 Prius and Prius Plug-in: Right rear of the cargo area.
  • Prius C (all years): Under the right side of the rear passenger seat.
  • Prius V wagon (all years): Right rear of the cargo area.
  • 2016 to 2022 Prius and Prius Prime: Left side of the engine compartment.
  • 2023 and newer Prius, Prius Prime, and Prius Plug-in: Right rear of the cargo area.

Hope this helps you find it.

Sounds like your 12v battery is shot and needs replacing. If you’re dealing with a 2004 to 2015 Prius or a Prius Plug-in, the jump start terminal is in the engine compartment fuse box. Same goes for all Prius V wagons and 2013 and newer Prius C models.

@Tory
I found this thing in the car that looks like it plugs into the cigarette lighter. The packaging says it’s a 12-volt charger and mentions connecting it to another car. Should I give that a shot? We used regular jumper cables before.

Sorry if this sounds dumb… I just really don’t know much about it.

@RuthMitchell
Those accessory outlets (like the cigarette lighter) on a Prius only work when the car is in Accessory, Ignition On, or Ready mode. You can’t charge the 12v battery from there. You need to use the jump start terminal under the hood or connect directly to the 12v battery in the trunk.

By the way, what year and model Prius are you working with?

@Tory
I’ll check tomorrow… I think it’s a Prius C, maybe from around 2012 or 2013? Just going off some pictures I found online.

@Tory
Actually, I just checked the manual… it’s a 2010.

@Tory
Found a Plug-2-Go in the glove compartment. Is it even worth trying to charge it with that?

Sounds like your 12-volt battery is completely gone and not charging at all. You probably just need a new one. If you’re not sure where the battery is, most regular Prius models have it in the trunk, either on the right or left side. The Prius C has it under the passenger seat, and the V model likely has it in the trunk too.

Best thing to do would be to jump it and take it to an auto parts store nearby. They usually test batteries for free since it’s likely to result in a sale anyway. If it turns out the battery is fine, it might just need a charge. Also, don’t freak out if the Prius shows a bunch of error codes after the battery is low or replaced. Sometimes it just glitches out like that.

@Baer
I drove it around tonight, but it wouldn’t stop beeping. I guess that might be connected to the battery being low. I’m planning to take it to AutoZone tomorrow since it’s pretty close by.

Also, quick update: I put in $10 worth of gas and it got me to half a tank. Wasn’t expecting that! Thanks for the tips.

@RuthMitchell
Yeah, Prius is great for saving money on gas. My wife and I only spend about $90 a month for both of ours. Once you get used to the fuel efficiency, it’s hard to go back to a regular car. Maintenance isn’t too bad either, and doing it yourself can save a lot. Oil changes are a bit annoying, but it’s still way cheaper than going to a shop.

@RuthMitchell
Was the beeping just one long tone (like beeeeeep) or was it more like a repeated beep beep beep?

Tory said:
@RuthMitchell
Was the beeping just one long tone (like beeeeeep) or was it more like a repeated beep beep beep?

It was just one long beeeeeep. At first, I thought it was the seatbelt sensor, but everyone was buckled up.