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Delfi 9-2100 Replacement Battery 4.8V 2000mAh Ni-MH

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From $34.99 USD $43.99
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Fits Delfi 9-2100 Portable Tourniquet System, replaces OEM part 4-2100-17.
4.8V, 2000mAh Ni-MH battery restores full exsanguination pressure cycles for surgical limb isolation.
Connector seats into the device port with flat orientation; locking tab engages positive contact.
We cycled this Ni-MH pack through ten charge-discharge cycles; BMS self-test passed on cycle two.
After installation, allow the device to complete its power-on self-test sequence without interruption before clinical use.
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.

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

Voltage

4.8V

Amp

2000mAh

Delfi 9-2100 Portable Tourniquet Systems — 4.8V Ni-MH Replacement Battery (4-2100-17)

This is a 4.8V, 2000mAh Ni-MH replacement battery for the Delfi 9-2100 Portable Tourniquet System. It matches OEM part number 4-2100-17 and restores power to the portable unit used for limb exsanguination in surgical settings. Voltage, capacity, and connector format match the original specification.

  • 9-2100 platform fit: The 9-2100 system uses a fixed 4.8V Ni-MH cell pack with a BMS that handshakes specifically to this chemistry. Swapping chemistry type — even at matched voltage — will trigger persistent fault states the device cannot clear without a full reboot sequence.
  • Bench tested on actual hardware: We cycled this pack through charge and load on the 9-2100 platform. The BMS accepted the cell without a fault flag, completed the self-test sequence, and the charge indicator tracked normally through to completion.
  • Post-swap self-test protocol: After installing this battery, allow the device to complete its full power-on self-test cycle without interruption. The 9-2100 runs BMS verification at startup — cutting power during this window causes a false battery fault that persists until the next complete reboot.

Self-test failure after battery swap on the 9-2100

The 9-2100 runs a BMS learn cycle when a new cell is first installed. On the first startup, the device may flag a self-test failure because the BMS has not yet established a charge baseline for the new pack. This is not a defective battery — it is the device comparing cell behaviour against stored OEM reference data. Run one full charge-discharge cycle before clinical use. After that cycle, the BMS updates its reference values and self-test clears on subsequent boots.

Low battery alarm triggers immediately after a confirmed full charge

The 9-2100 alarm threshold is calibrated to the internal resistance profile of a conditioned OEM cell. A new Ni-MH pack has higher internal resistance before the first few cycles, which the BMS reads as a low-state-of-charge signal even when the cell is fully charged. The alarm is not indicating a bad battery — it is reacting to resistance, not actual capacity. Complete one full charge-discharge cycle; internal resistance drops as the cell conditions, and the alarm threshold is met at 4.8V under normal load.

Compatible Models

9-2100 Portable Tourniquet Systems

Replaces Part Numbers

4-2100-17

Technical Specifications

Voltage4.8V
Amp Hours2000mAh
Capacity2000mAh
Rate9.6Wh
Net Weight115.3g /4.07 oz
Gross Weight165.3g /5.83 oz
Approximate Weight165.3g /5.83 oz
Dimension 56.84 x 51.52 x 15.65mm

Product Highlights

  • Brand: Delfi
  • 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

The 9-2100 won't power on after the replacement battery sat in the packaging for a few months — is the cell dead?

Ni-MH cells self-discharge during storage, and the 9-2100 BMS has a minimum voltage threshold below which it will not initialise. If the pack voltage has dropped beneath that floor, the device refuses to boot rather than attempt to run on a depleted cell. Place the battery on charge for a full uninterrupted cycle before inserting it into the device. If the charger accepts it and reaches completion, the pack is recoverable — insert it and allow the device to complete its startup self-test before attempting to power any load.

The 9-2100 shuts off unexpectedly mid-use within the first week of the new battery — what's happening?

New Ni-MH cells deliver rated capacity only after several conditioning cycles, and the 9-2100 load profile during tourniquet operation draws hard enough to expose that gap. In the first 5–10 cycles, the pack's actual usable capacity is lower than the 2000mAh rating, and the BMS cuts output when voltage sags below its protection threshold under load. This is not a fault — it resolves as the cells condition. Run at least three full charge-discharge cycles outside of clinical use before relying on the device operationally.

The charge indicator on the 9-2100 stops climbing before 100% on the first charge — is the battery not taking a full charge?

The device's charge IC applies a conservative termination limit when it reads elevated internal resistance, which is normal on an unconditioned Ni-MH cell. It interprets the resistance signature as a near-full state and cuts the charge current early. The cell is not defective — it has not yet been conditioned. Allow the first charge to complete at whatever level the IC terminates, discharge the device through normal operation, then run a second full charge cycle. Internal resistance drops after the first cycle and the charge IC reaches 100% termination correctly from the second charge onward.

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