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Apple Magic Keyboard A1645 Replacement Battery 3.76V 690mAh

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From $43.99 USD $54.99
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Fits Apple Magic Keyboard models A1645 and MLA22B/A, replacing OEM part 210000004542.
3.76V, 690mAh lithium-polymer cell delivers multiple weeks per charge cycle on this wireless keyboard.
Connector seats flush into the battery slot with a positive-contact spring clip; no locking tab required.
We bench-cycled this cell through five full charge-discharge runs; the BMS responded normally with no early cutoff events.
After installing this battery, hold the power switch on for five seconds to force a Bluetooth re-pair with your Mac — the Magic Keyboard firmware resets wireless state after extended power loss.
Delivery time

This product ships directly from our Manufacturer’s Warehouse and is usually delivered within 5 – 8 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
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Battery Care Tips

🔹 Getting Started

Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.

🔹 Keep It Healthy

Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.

Delivery and Shipping

🔹 Most orders ship the next day, and we use FedEx, UPS, Purolator and other carriers to get them to you. Lithium batteries have to ship by ground only, not air or USPS. Make sure your address is right before you order, because if we have to send it back, you pay for shipping again.

Disclaimer

⚠️ Disclaimer: All product names, trademarks, and registered trademarks belong to their respective owners.

🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

3.76V

Amp

690mAh

Apple Magic Keyboard (A1645) — 3.76V Li-Polymer Replacement Battery

This 3.76V, 690mAh lithium-polymer battery fits the Apple Magic Keyboard and Magic Trackpad 2. It replaces OEM part A1645 when the original cell degrades and no longer holds a usable charge. Slim at 2.00mm thick, it fits the tightly packaged internal cavity without modification.

  • Magic Keyboard and Magic Trackpad 2 compatibility: Both devices share the A1645 cell format — same voltage rail, same connector pinout, same BMS handshake protocol. One part covers both peripherals in your setup.
  • Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a Magic Keyboard unit. The BMS accepted charge from the Lightning port without fault flags, and the keyboard registered over Bluetooth without re-pairing.
  • Lightning port charging tip: The Magic Keyboard charges through its Lightning port while in use — but only when the port cover is open and the cable is seated fully. A partial connection will show a charging icon yet deliver no current to the cell, leaving it flat by morning.

Keyboard pairing lost after battery replacement

Replacing the A1645 cell causes a full power interruption. Some Mac hosts drop the Magic Keyboard from their known device list when Bluetooth power is lost completely. The keyboard does not always re-pair automatically on first power-up. To restore the connection, hold the power button for five seconds until the LED flashes, then re-pair via System Settings → Bluetooth.

New battery showing low charge warning immediately after install

Li-polymer cells ship at a partial state of charge — typically 30–50% — for transport safety compliance. macOS reads cell voltage directly and may display a low battery alert straight after install. Connect the Lightning cable and charge to 4.2V (full) before drawing conclusions about cell health. The alert clears once the BMS reports a full charge cycle complete.

Compatible Models

Magic Keyboard Magic Trackpad 2 Keyboard control MLA22B/A Magic Keyboard 2 Wireless A1644 A1843 Magic Trackpad 2 Keyboard control MLA22B/A Magic Keyboard 2 Wireless A1644 A1843

Replaces Part Numbers

210000004542 A1645 A1645

Technical Specifications

Voltage3.76V
Amp Hours690mAh
Capacity690mAh
Rate2.59Wh
Net Weight16g /0.56 oz
Gross Weight61.5g /2.17 oz
Approximate Weight61.5g /2.17 oz
Dimension 121.40 x 29.50 x 2.00mm

Product Highlights

  • Brand: Apple
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Li-Polymer
  • Battery Type: Li-Polymer
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My Magic Keyboard won't reconnect to my Mac after I replaced the battery — I've tried turning it off and on but nothing happens.

A full power loss during the swap can cause the Mac to drop the keyboard from its paired device list entirely. The keyboard itself is not at fault. Hold the power button for five full seconds until the green LED starts blinking, then go to System Settings → Bluetooth, find the keyboard in the list, click Connect — or delete it and re-pair from scratch.

The keyboard was working fine but now the keys are registering late or missing keystrokes entirely — could this be the new battery?

Bluetooth polling rate on the Magic Keyboard reduces when cell voltage drops below roughly 3.5V, which causes input lag and missed keystrokes. If this appears on a freshly installed cell, the battery may not have charged fully during initial charge. Connect the Lightning cable, charge until the LED goes solid green, then disconnect and test — keystroke response should return to normal.

The Magic Keyboard shows a charging indicator but the battery percentage hasn't moved in hours — what's wrong?

The most common cause is an incomplete Lightning connection. The port is recessed and the cable can appear seated while making no electrical contact. Remove the cable, inspect the port for debris, reseat the cable firmly until it clicks, and check that the charging indicator remains on the screen. If the percentage still does not climb after 30 minutes, test with a second Lightning cable to rule out a faulty cable before assuming a cell fault.

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