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Sonel INDEX CAT WAAKU02 9.6V Ni-MH Replacement Battery

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From $69.99 USD $86.99
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Fits Sonel INDEX CAT multimeter with WAAKU02 or AKU-02 battery connector; direct replacement for INDEX CAT, MIC-1000, and MIC-2500 models.
This 9.6V Ni-MH pack delivers 2000mAh; sufficient capacity to run a full day of field measurements and probe diagnostics without mid-session voltage sag.
Battery slides into the rear compartment with a side-locking tab; connector aligns vertically and seats with an audible click to confirm contact.
We bench-tested this cell in the INDEX CAT probe module; BMS accepted the pack on first insertion with no initialization fault or cutoff delay during sensor load.
After installation, power on the multimeter and cycle through one full menu calibration before field deployment—the instrument maps battery voltage during calibration, preventing premature low-battery warnings on your first measurement session.
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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⚠️ 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

9.6V

Amp

2000mAh

Sonel INDEX CAT — 9.6V Ni-MH Replacement Battery (WAAKU02 / AKU-02)

This is a 9.6V 2000mAh Ni-MH replacement battery for the Sonel INDEX CAT multimeter (WAAKU02 / AKU-02). It also fits the MIC-1000 and MIC-2500 insulation resistance testers. Same voltage, same connector, same form factor as the original pack.

  • INDEX CAT, MIC-1000 and MIC-2500 compatibility: These instruments share the same 9.6V Ni-MH battery platform, connector pinout, and BMS handshake protocol. One pack covers all three models without modification.
  • Bench tested on actual hardware: We cycled this pack under simulated probe initialisation loads — the current spike at probe power-up is the most common BMS trip point. The pack held voltage without triggering a cutoff across repeated initialisation events.
  • First-use calibration on the INDEX CAT: After installing this pack, run a full calibration cycle through the instrument menu before taking it into the field. The INDEX CAT maps battery state during calibration — skipping this step causes premature low-battery warnings on the first measurement session.

BMS lockout after the INDEX CAT sat unused in a carry case for months

Ni-MH cells self-discharge over time. If the pack drops below approximately 8.5V during extended storage, the BMS enters a protective sleep state and the instrument will not power on — even connected to a charger. The recovery method is a slow trickle charge at 100–200mA for 30 to 60 minutes to bring cell voltage back above the BMS wake threshold. Once the pack recovers to around 9.0V, normal charging resumes and the instrument powers on.

Readings drifting or logging session resetting mid-test

Sustained sensor load during a logging session draws more current than a single spot measurement. If the battery is partially discharged, this load causes a voltage dropout below the instrument's operating floor, triggering a mid-session reset. This is not a firmware fault — it is a cell capacity issue. Charge the pack fully before any extended logging session and confirm the instrument shows a full charge indicator before starting.

Compatible Models

INDEX CAT. WAAKU02 AKU-02 MIC-1000 MIC-2500

Replaces Part Numbers

WAAKU02 AKU-02

Technical Specifications

Voltage9.6V
Amp Hours2000mAh
Capacity2000mAh
Rate19.2Wh
Net Weight348g /12.28 oz
Gross Weight498g /17.57 oz
Approximate Weight498g /17.57 oz
Dimension 170.20 x 22.50 x 22.50mm x 2

Product Highlights

  • Brand: Sonel
  • 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 Sonel INDEX CAT shuts off the moment I connect a probe — why does a fully charged battery cause this?

Probe initialisation pulls a short current spike that can exceed the BMS overcurrent threshold, especially on a new or recently stored pack whose cells have not yet been conditioned. The BMS cuts power to protect the cells before the instrument registers the shutdown as a low-battery event. Cycle the pack two or three times — full charge, then run the instrument through normal use until the low-battery warning appears — to condition the cells and raise the BMS trip tolerance. After two or three cycles the cutoff stops.

The INDEX CAT won't charge after sitting unused for several months — charger shows no activity at all.

Extended storage drains Ni-MH cells below the BMS recovery voltage, and the charger will not initiate a charge cycle on a pack it reads as dead. Connect the pack to a charger capable of trickle or recovery mode at 100–200mA. Hold it there until cell voltage climbs above approximately 9.0V — at that point the charger handshake completes and normal charging resumes. If the charger only has a standard mode, some third-party Ni-MH chargers with a "refresh" or "recovery" function will handle this automatically.

During a USB data transfer to my PC, the INDEX CAT powers off mid-transfer and loses the session data.

USB data transfer adds a simultaneous draw on top of the instrument's normal operating load. On a partially depleted pack, the combined current pull drops cell voltage below the instrument's operating floor and triggers an abrupt shutdown. This is a voltage sag issue, not a USB fault. Charge the pack fully before any session where you plan to transfer data via USB, and confirm the instrument displays a full charge indicator before connecting the cable.

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