Toyota Prius / Prius Prime 12V battery
Yes - the Toyota Prius / Prius Prime has a 12V auxiliary battery, separate from the high-voltage traction pack. The reported battery is a 140R / H4 / LN1 AGM, in the trunk (rear cargo area). A dead 12V is the number-one thing that strands an EV.
Key takeaways
- The Toyota Prius / Prius Prime has a 12V auxiliary battery, separate from the high-voltage traction pack.
- Reported 12V battery: 140R / H4 / LN1, AGM.
- Location: Trunk (rear cargo area).
- A dead 12V often leaves the car unable to unlock or power on - keep it healthy.
EV and hybrid 12V specs are not reliably published by makers and change by year, trim, and region. The table below is the commonly reported battery for the years shown, with our source - confirm against the battery in your car before buying.
| Years | 12V battery | Location | Source |
|---|---|---|---|
| 2016-2022 | 140R / H4 / LN1AGM | Trunk (rear cargo area) | priuschat.com |
Why the 12V matters on an EV
The big traction pack drives the wheels, but the little 12V battery runs the computers, locks, and screens - and it is what powers the car up in the first place. If the 12V dies, the Toyota Prius / Prius Prime may not unlock or switch on even with a full traction pack, which is why a dead 12V is the most common way an EV gets stranded. Most 12V batteries last 3 to 5 years; replacing one is usually straightforward once you can get power to open the compartment.
See the full EV & hybrid 12V battery guide →
Frequently asked
Does the Toyota Prius / Prius Prime have a 12V battery?
Yes. Like every EV and hybrid, the Toyota Prius / Prius Prime has a small 12V auxiliary battery, separate from the high-voltage traction pack. It runs the electronics and wakes the car up, and when it dies the car often will not power on at all.
What 12V battery does the Toyota Prius / Prius Prime use?
The reported 12V battery is a 140R / H4 / LN1 AGM, located in the trunk (rear cargo area). Confirm against the battery in your own car, as the exact size can change by year and trim.
Where is the 12V battery in the Toyota Prius / Prius Prime?
Trunk (rear cargo area). On EVs and hybrids the 12V is often in the frunk, under a seat, or in the rear cargo area rather than under the hood.