Disconnect and Reconnect the 12V Battery

Disconnecting the 12 V battery on your Polestar 2 (2021–2024) is something you’ll do before a long storage lay-up, ahead of electrical work or work near the airbags, or to recover the car if the low-voltage side has gone flat. This is the low-voltage 12 V battery only. The high-voltage drive battery is a separate, sealed system and must never be touched — you only ever handle the 12 V unit here. Even on an EV the 12 V battery does the same everyday jobs as on any car: it wakes the electronics, runs the lights and controls, and lets the car power up. Take the terminals off in the right order, give it a moment, and reconnect in reverse and the car settles back cleanly.

Where the 12 V Battery Is

The 12 V battery is in the rear, under the luggage-compartment (boot) floor. Lift the boot floor panel and fold back the trim to expose it. You’re looking for two clamped terminals: the negative (−) earth/ground lead, usually black, and the positive (+), usually red and often under a cover. Identify both before you touch a spanner.

High voltage: never touch the orange high-voltage cabling. This procedure is only the 12 V battery.

First, a Few Checks

• Power the car fully down and make sure it is not in READY — the drive system must be off, not just the screen dark.
• Take the key away from the car so it doesn’t wake and re-power the electronics.
• Switch off the lights, climate, and anything drawing power.
• Note your personal settings, though most are tied to your Polestar profile and return when you sign in.
• Wait a couple of minutes for the modules to power down, and have the right spanner, gloves, and eye protection to hand.

Find the 12 V Battery First

Disconnecting Safely

1. Turn the EV power switch OFF and wait a couple of minutes for the systems to power down.
2. Lift the boot floor to reach the battery.
3. Slacken and remove the negative (−) terminal first, then move the cable clear of the post.
4. Only then loosen and lift off the positive (+) terminal.
5. If you’re working near the airbags, wait a few minutes after disconnecting before you begin.

Reconnecting and Re-initialising

Reverse the order: fit the positive (+) first, then the negative (−) last, and tighten both clamps securely. Then a few things need settling:

• Power windows — re-initialise the one-touch/anti-pinch by holding each switch fully up at the top limit and fully down at the bottom.
• Tyre pressure monitor — re-store the pressures from the touchscreen, or let a short drive re-establish them.
• Allow the car a minute to wake fully before driving off.

If Something Isn’t Right Afterwards

• Check both clamps are tight and fully seated — a loose earth is the usual cause of odd electrical behaviour.
• Warning messages often clear after a short drive once the car sees everything working normally.
• If a window won’t auto-close, repeat the hold-at-the-limits relearn.
• If the 12 V side keeps going flat, rule out a genuinely tired battery — fit a like-for-like AGM unit of the correct rating.
• If an alert stays on, it has stored a code — look it up on autodtcs.com.

Frequently Asked Questions

Where is the 12 V battery on a Polestar 2?

In the rear, under the luggage-compartment (boot) floor — separate from the high-voltage drive battery. Lift the boot floor panel to reach it.

Is it safe to disconnect the battery on an EV?

Yes — the 12 V battery is low voltage and owner-safe to handle. Never touch the orange high-voltage cabling; that system is sealed and only for trained technicians.

Which terminal do I disconnect first?

The negative (−) terminal first, and reconnect it last. That removes the ground path before you work on the positive side.

What needs resetting afterwards?

Mainly the one-touch windows and the tyre-pressure monitor. Most personal settings are tied to your Polestar profile and return when you sign in, and a short drive clears most transient messages.

Does a new 12 V battery need coding?

Fit a like-for-like AGM unit of the correct rating. A straightforward like-for-like swap generally needs no special coding, but matching the original battery type keeps the charging system happy.

Can I jump-start it instead of disconnecting?

For a flat 12 V battery, the car has a jump/boost point so you can wake it without pulling the terminals. Disconnecting is only needed for storage or work near the airbags and electrics — and you never jump from the high-voltage system.

To relearn the windows, hold each switch at its upper and lower limits for a moment. If a warning stays on after everything is reconnected, decode it on autodtcs.com.