Disconnect and Reconnect the Battery

Disconnecting the 12 V battery on a Kia Stonic (YB, 2017–present) is a simple engine-bay job most owners can do at home with a single spanner. You’ll want to isolate the battery when you renew it, before electrical or bodywork near the wiring, ahead of long storage, or to give the car a clean power-down when a niggle won’t clear. This guide covers safe disconnection in the correct order and the short list the Stonic needs re-taught afterwards — most of which it sorts out within a drive or two.

Where the Battery Is

The 12 V battery sits in the engine bay, behind a cover. Lift the cover and you’ll see the two terminals: the negative (−) post carries the earth and usually has a plain black clamp, while the positive (+) post sits under a red or coloured cap. The petrol and diesel Stonic has no high-voltage system to worry about. The 48 V mild-hybrid version keeps its 12 V battery here too and the 12 V work below is owner-safe on it — only the small 48 V unit and its own cabling are specialist items you should leave alone.

Getting Ready

• Make sure the ignition is fully off and the dash has gone dark.
• Carry the smart key several metres away so the car can’t wake and re-power the circuits.
• Switch off the lights, climate and accessories, and shut the doors and boot so the electronics go to sleep.
• Note your radio/security code if you keep one, though the radio usually reloads without it.
• Wait a minute or two for the modules to power down before loosening anything.
• Have the right spanner (usually 10 mm), gloves and eye protection ready.

Disconnecting

1. Switch the ignition off, remove the smart key and wait a minute for the electronics to sleep.
2. Slacken and lift the negative (−) terminal first, then tuck the lead aside so it can’t spring back onto the post.
3. If you’re removing the battery, lift the positive cap, undo the positive (+) clamp next, then release the hold-down and lift the battery out level.

Reconnecting & Re-teaching

1. Seat the battery, refit the hold-down, then reconnect the positive (+) first and tighten.
2. Connect the negative (−) last, nip both clamps up firmly, and refit the cover.
3. Switch on and reset the clock; the radio usually reloads on its own.

The Stonic doesn’t need the battery coded — fit a like-for-like battery and the car is happy. Just re-teach the items below.

What You’ll Need to Reset Afterwards

Cutting power clears a few learned settings. On the Stonic you’ll typically need to:

• Reset the clock and radio presets; the radio itself usually reloads.
• Re-initialise the one-touch/anti-pinch windows — see our Stonic window guide.
• If your car has a sunroof, it may also need re-initialising before it will one-touch or auto-close again.
• Let any minor warning lights self-clear over a short drive once everything is powered back up.

If a Warning Light Stays On or the Car Feels Off

• Check both clamps are tight and clean — a loose earth causes the strangest faults.
• Drive gently for a few miles so the modules can relearn their idle and charge values.
• If the windows or sunroof won’t one-touch, run the re-initialise again from the fully closed position.
• Rule out a genuinely flat or old battery — a weak battery throws random warnings no reset will fix.
• Read any stored code to see what actually tripped before chasing it.

Registering or Coding the New Battery

Depends on the model. Cars with a battery sensor (IBS) need the battery data reset so charging is managed for a new battery — usually with a diagnostic tool (dealer or a capable scanner). Simpler models with no sensor need nothing beyond a short relearn drive.

Frequently Asked Questions

Where is the 12 V battery on the Kia Stonic?

It’s in the engine bay, behind a cover. That’s true of the petrol, diesel and 48 V mild-hybrid versions — the mild hybrid keeps its 12 V battery in the same place, separate from the small 48 V unit.

Which terminal first on the Stonic?

Disconnect the negative (−) first and reconnect it last. On refit, positive goes on first, negative last — this keeps the spanner away from an accidental short.

Does the Kia Stonic battery need coding?

No — just fit a like-for-like battery and re-teach the windows (and the sunroof if fitted). There’s no battery registration step needed on this car.

Will I lose my radio?

No code is normally needed — the radio reloads on its own. You’ll just reset the clock and re-enter any presets.

Will disconnecting clear fault codes or the service light?

It can clear some transient codes but won’t reset the service reminder — that has its own procedure. See our Stonic service reset. A genuine fault will simply return until it’s fixed.

Can I jump-start it instead of disconnecting?

If you only need to recover a flat battery, yes — a jump-start avoids the disconnect. Only take the battery off to renew it or for electrical work.

For any warning light that stays on after all this, look up the code on autodtcs.com to see what it means before you act on it.