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Topwise Z91 Payment Terminal Replacement Battery 7.4V 2500mAh

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From $53.99 USD $66.99
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Fits Topwise Z91 payment terminal, replaces OEM battery YJ455385.
7.4V, 2500mAh capacity delivers steady power through card processing and receipt printing cycles.
Connector slides into vertical slot with locking tab — seat until you hear the click.
We ran full transaction cycles on the Z91 platform; BMS accepted handshake on first boot without fault codes.
After installation, complete one full transaction cycle before deploying in live environment — terminal calibrates charge indicator during normal operation.
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

7.4V

Amp

2500mAh

Topwise Z91 — 7.4V Li-ion Replacement Battery (YJ455385)

This is a 7.4V, 2500mAh Li-ion replacement battery for the Topwise Z91 mobile payment terminal. It replaces OEM part number YJ455385 and fits the Z91 form factor directly. The battery slots into the terminal's rear bay and connects via the standard pogo-pin contact plate.

  • Z91 platform fit: The Z91 runs a dedicated battery bay with a fixed contact layout and a BMS handshake over the data line. This cell matches that voltage rail and communicates the correct cell parameters so the terminal's charge IC does not reject it at boot.
  • Bench tested on actual hardware: We cycled this cell through the Z91's full charge IC sequence, verified BMS handshake acceptance, and confirmed the terminal completed its PCI boot sequence without fault codes on the status screen.
  • First transaction cycle after swap: After fitting this battery, run at least one complete transaction — card tap through receipt print — before deploying in a live environment. The Z91 maps battery capacity during normal operation and requires a full power cycle to calibrate the charge indicator correctly.

Terminal not completing PCI boot sequence after battery swap

The Z91's PCI boot sequence includes a battery validation step where the charge IC reads cell parameters from the BMS before allowing the OS to load. A new cell that has not completed its first charge-discharge cycle may sit at a resting voltage that the charge IC flags as ambiguous. The terminal stalls at the boot splash screen or cycles back to the Topwise logo repeatedly. Plug the terminal into its dock, allow a full charge to 8.35V, then power on — the boot sequence completes normally after that first charge cycle.

Battery indicator stuck at 99% through the first full charge

On a new cell, the Z91's charge IC enters top-off mode when the cell reaches approximately 8.3V, delivering a low taper current to bring it to the true full-charge threshold. During this phase the display holds at 99% rather than stepping to 100%. This is normal behaviour — the IC is not frozen, it is completing the CV stage of the charge cycle. Leave the terminal on the dock until the charge LED goes green, which signals the IC has exited top-off mode and logged the full capacity baseline for the gauge.

Compatible Models

Z91

Replaces Part Numbers

YJ455385

Technical Specifications

Voltage7.4V
Amp Hours2500mAh
Capacity2500mAh
Rate18.5Wh
Net Weight111g /3.92 oz
Gross Weight161g /5.68 oz
Approximate Weight161g /5.68 oz
Dimension 90.00 x 54.85 x 9.40mm

Product Highlights

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

Frequently Asked Questions

My Topwise Z91 reboots every time the receipt printer fires — is the battery causing this?

Yes — the receipt printer motor draws a short, sharp current spike that can trip the BMS overcurrent threshold on a degraded original battery. This replacement cell is rated to handle the combined printer, display, and wireless draw without hitting that cutoff. If reboots continue after fitting the new battery, check that the terminal firmware is current, as older builds have an aggressive BMS overcurrent limit that a firmware update corrects.

The Z91 won't power on at all after sitting unused in a drawer for a few months — what happened?

Self-discharge over a long storage period can pull the cell below the BMS recovery threshold, typically around 2.5V per cell. At that point the BMS locks output to protect the cell, and the terminal shows nothing when you press the power button. Connect the terminal to its dock charger and leave it for 30–40 minutes — most Z91 charge ICs will attempt a pre-charge recovery pulse at low current to bring the cell back above the threshold before switching to normal charge rate.

The Z91 feels noticeably warm during a busy transaction period — is that a fault?

Not necessarily. The Z91 draws simultaneously from the display backlight, the wireless radio, and the printer during a high-volume period, and that combined load generates heat at the cell. Warm to the touch is within spec; hot enough to be uncomfortable or causing throttled transaction speed is not. If the terminal is running transactions in direct sunlight or in an enclosed stand with no airflow, move it to a ventilated position — the thermal ceiling for the Z91 battery bay is 45°C, above which the BMS will reduce output current to protect the cell.

Payment & Security

Payment methods

  • American Express
  • Apple Pay
  • Diners Club
  • Discover
  • Google Pay
  • Mastercard
  • PayPal
  • Shop Pay
  • Visa

Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.

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