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AHB322028 TomTom Runner Cardio Smartwatch Battery 3.8V 190mAh

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From $23.99 USD $29.99
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Fits TomTom Runner Cardio, Runner, and Spark 8rs00 smartwatches, replacing OEM part AHB322028.
3.8V, 190mAh lithium-polymer cell delivers the energy density required for multi-day fitness tracking and heart rate monitoring.
Connector is a two-pin pogo contact pad, aligned flat to the watch circuit board with no locking tab required.
We bench-tested the cell on a Runner Cardio platform; BMS accepted the charge handshake cleanly, fuel gauge registered from zero without error codes.
After fitting this cell, place the watch on its magnetic charger immediately and charge to 100% — the fuel gauge IC cannot calibrate without a full charge cycle from near-zero after a battery swap.
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.

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⚠️ 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

3.8V

Amp

190mAh

TomTom Runner Cardio / Spark — 3.8V Li-Polymer Replacement Battery (AHB322028)

This is a 3.8V, 190mAh lithium-polymer cell for the TomTom Runner Cardio, Runner, and Spark 8rs00 smartwatches. It replaces part number AHB322028 and fits the same 27.40 × 18.14 × 2.50mm cavity as the original. Swap it when the watch no longer holds charge through a full training session.

  • Runner Cardio, Runner, and Spark 8rs00 fit: All three models share the same AHB322028 cell format, connector pinout, and BMS handshake protocol. One replacement cell covers the entire group without modification.
  • Bench tested on actual hardware: We cycled this cell through charge and discharge on a Runner Cardio unit. The BMS accepted the new cell without error flags, and the fuel gauge IC registered capacity correctly after a full charge cycle.
  • First charge after swap: After fitting this cell, place the watch on its magnetic charger immediately and charge to 100% before use. The fuel gauge IC on this platform loses its calibration reference when the cell is removed — it cannot reset without a full charge cycle from near-zero.

Why the Runner Cardio shows 0% immediately after a battery swap

The TomTom Runner Cardio uses a fuel gauge IC to track state-of-charge, not a simple voltage read. When the cell is disconnected, that IC loses its reference point entirely. It comes back up reading zero because it has no history on the new cell. Placing the watch on its charger and running a full charge cycle to 100% gives the IC a fixed upper boundary to calibrate from. After one complete charge, the percentage display will behave normally.

New battery draining in under a day instead of the expected multi-day life

A 190mAh cell is a small reserve, and continuous optical heart rate monitoring pulls a consistent current draw that adds up fast. If the Runner Cardio is set to always-on heart rate tracking, the sensor alone can flatten the cell well before a 24-hour mark. Check the HR monitoring mode in the TomTom MySports app and switch from continuous to activity-only if all-day battery life is the priority. Also confirm the watch face backlight timeout is set to its shortest option, as that display draw compounds quickly on a cell this size.

Compatible Models

Runner Cardio Runner Spark 8rs00

Replaces Part Numbers

AHB322028

Technical Specifications

Voltage3.8V
Amp Hours190mAh
Capacity190mAh
Rate0.72Wh
Net Weight3.4g /0.12 oz
Gross Weight28.4g /1.00 oz
Approximate Weight28.4g /1.00 oz
Dimension 27.40 x 18.14 x 2.50mm

Product Highlights

  • Brand: TomTom
  • 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 TomTom Runner Cardio won't pair with my phone after swapping the battery — what happened?

Removing the battery cuts power completely, which terminates any active BLE session the watch held with your phone. The pairing record on the watch side is wiped during that hard power loss. Open your phone's Bluetooth settings, forget the TomTom device, then re-pair from scratch through the MySports app. The watch does not need a factory reset — just a clean re-pair.

The magnetic charger doesn't seem to be charging the watch after I reassembled it — the indicator never comes on.

The charge contacts on the Runner Cardio are small pads on the underside of the case, and reassembly can shift the internal PCB just enough to misalign them. Remove the watch from the charger, press the case halves together firmly, and re-seat it on the charger. If the indicator still does not light, check that the magnetic charger is snapping to center — an off-axis connection will not transfer current even if it physically holds.

The heart rate sensor seems to be killing this new battery faster than it did with the worn-out original — is something wrong?

This is normal for the first several charge cycles on a new cell. The optical HR sensor draws a fixed current regardless of battery age, but a fresh cell at full 190mAh capacity actually powers the sensor longer per cycle, which can make continuous HR logging more active than it appeared on a degraded cell. The apparent drain rate settles after the fuel gauge IC completes two or three full charge-discharge cycles and recalibrates. If it persists past five cycles, check that HR mode is set to activity-only rather than continuous, and confirm firmware is up to date via MySports.

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