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Casio QT-6000 Replacement Battery HHR-21H3G1B 3.6V 2000mAh

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From $28.99 USD $35.99
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Fits Casio QT-6000, QT-6100, QT-6200, QT-6600 payment terminals; replaces OEM part numbers HHR-21H3G1B, HHR-21HL3G1C, HHR-21HL3G1.
3.6V, 2000mAh Ni-MH cell delivers steady output through card processing, wireless transmission, and receipt printer cycles without voltage sag.
Connector slides straight into the battery slot with a single locking tab; seat firmly until the retention clip locks with a click.
We bench tested the pack on a QT-6000 under transaction load—BMS accepted the cell cleanly and held voltage through simulated card reads and print jobs.
After installation, run one complete transaction cycle before deploying in a live environment; the terminal maps battery capacity during normal operation and requires one full power cycle to calibrate the charge indicator.
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

3.6V

Amp

2000mAh

Casio QT-6000 / QT-6100 / QT-6200 / QT-6600 — 3.6V Ni-MH Replacement Battery (HHR-21H3G1B)

This 3.6V, 2000mAh Ni-MH battery replaces the OEM pack in the Casio QT-6000 series portable payment terminals. It fits the QT-6000, QT-6100, QT-6200, and QT-6600 models. All four share the same battery bay, connector pinout, and charge circuit — one part number covers the range.

  • QT-6000 series platform fit: Casio built the QT-6000, QT-6100, QT-6200, and QT-6600 on a common chassis with an identical 3.6V battery rail and the same BMS handshake protocol. This replacement matches that voltage and connector geometry exactly — no adapters, no wiring changes.
  • Bench tested on actual hardware: We cycled this cell through the QT-6000's charge IC and verified the BMS accepted the new pack without fault codes. The charge controller completed its top-off phase normally and the terminal logged a full capacity reading after one complete boot-charge cycle.
  • First deployment tip for POS terminals: After installation, run one complete transaction cycle — receipt print included — before putting the terminal into a live queue. The QT-6000 maps battery capacity during normal operation and won't display an accurate charge indicator until it has completed at least one full power cycle under real load.

Terminal not completing PCI boot sequence after battery swap

The QT-6000 runs a PCI compliance check during every cold boot. On a freshly installed Ni-MH cell, the terminal's BMS handshake can time out if the cell voltage hasn't stabilised above the boot threshold — typically around 3.4V measured at the connector. This causes the boot sequence to halt before the payment application loads. Fully charge the new battery before the first power-on, then allow the terminal to complete one uninterrupted boot cycle.

Terminal won't power on after sitting unused in a drawer

Ni-MH cells self-discharge at roughly 1–2% per day at room temperature. A QT-6000 left unused for several months can see its cell drop below the BMS recovery threshold — around 3.0V — causing the terminal to appear completely dead. Connect the terminal to its dock or AC adapter and leave it on charge for a minimum of 4 hours before attempting to power on. If the charge LED doesn't activate within 10 minutes, check the dock contacts for corrosion and clean with isopropyl alcohol before retrying.

Compatible Models

QT-6000 QT-6100 QT-6200 QT-6600 QT-660

Replaces Part Numbers

HHR-21H3G1B HHR-21HL3G1B HHR-21HL3G1C

Technical Specifications

Voltage3.6V
Amp Hours2000mAh
Capacity2000mAh
Rate7.2Wh
Net Weight97g /3.42 oz
Gross Weight132g /4.66 oz
Approximate Weight132g /4.66 oz
Dimension 128.70 x 19.50 x 17.00mm

Product Highlights

  • Brand: Casio
  • Manufacturer: CS
  • Series: Standard
  • Color: Green
  • Product Type: Ni-MH
  • Battery Type: Ni-MH
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My QT-6000 reboots every time the receipt prints — is this the battery?

Yes, and it's a specific failure mode. The thermal printer motor draws a short burst of current that the degraded original cell can't sustain, causing voltage to sag below the BMS cutoff and triggering a reboot. A new 2000mAh cell at full charge handles that current spike cleanly. Charge the replacement fully before testing, then run a receipt print as your first live check.

The battery indicator is stuck at 99% after charging the new pack overnight — is something wrong?

Nothing is wrong. The QT-6000's charge IC enters a top-off phase on a new Ni-MH cell and holds the indicator at 99% until it completes a full characterisation cycle. This is normal behaviour with a fresh cell — not a fault. Run the terminal through one complete transaction cycle including a receipt print and a full power-down, and the indicator will update to a calibrated reading.

The terminal was working fine on the new battery but now it feels warm during a busy shift — should I be concerned?

Some heat is expected. The QT-6000 draws simultaneously from the display backlight, the wireless radio, and the printer during a high-transaction period, and that combined load warms the cell and the housing. If the terminal stays below uncomfortable-to-touch levels and doesn't shut down, it's operating within normal parameters. If it does cut out, let it cool for 5 minutes and check that the battery contacts are seated flush — a partially seated pack increases resistance and heat at the connector.

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