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Geo-Fennel FL 400 HA-G Replacement Battery 2.4V 8000mAh

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From $76.99 USD $91.99
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Fits Geo-Fennel Rotationslaser FL 400 HA-G, replaces OEM part 10-05506.
2.4V at 8000mAh delivers stable power to the laser motor and electronics throughout a full shift on site.
Slide connector orients in a single direction; locking tab secures pack flush against the instrument body.
We bench-tested this Ni-MH pack in the FL 400 chassis — voltage held steady under sustained motor load with no cutoff events.
After installing this battery, run the laser's self-calibration routine before first field deployment so the instrument maps the new pack's voltage profile and prevents false low-battery warnings during measurement.
Delivery time

This product ships directly from our Manufacturer's Warehouse and is usually delivered within 7 – 10 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
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Fresh Battery, Worth the Wait

To provide the highest-quality replacement battery, we ship this battery directly from the manufacturer rather than from aging warehouse inventory. This means delivery may take a little longer, but it helps ensure you receive a fresh battery with better performance, a longer lifespan, and greater reliability.

Estimated delivery: 7–10 business days
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🔹 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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Voltage

2.4V

Amp

8000mAh

Geo-Fennel Rotationslaser FL 400 HA-G — 2.4V Ni-MH Replacement Battery (10-05506)

This is a 2.4V Ni-MH 8000mAh replacement battery for the Geo-Fennel Rotationslaser FL 400 HA-G rotating laser level. It slots into the same battery compartment as the original pack and powers both the laser motor and the onboard electronics. OEM part numbers 10-05506 and GF-243000-18 both apply to this cell configuration.

  • FL 400 HA-G platform fit: The FL 400 HA-G runs a single low-voltage rail at 2.4V, which dictates a two-cell Ni-MH pack. The connector orientation and BMS handshake are matched to this rail — swapping to a higher-voltage pack would overdrive the motor driver board.
  • Bench tested on actual hardware: We cycled this pack through the FL 400 HA-G's motor-start sequence, which pulls a brief current spike as the rotation head reaches operating speed. The BMS held without tripping, and voltage recovered cleanly once the motor stabilised.
  • Post-install calibration on the FL 400 HA-G: After fitting this pack, run a full calibration cycle through the instrument menu before deploying on site. The FL 400 HA-G maps battery state during calibration — skipping this step causes premature low-battery warnings on your first measurement session.

Why the FL 400 HA-G throws a low-battery warning immediately after a new pack is fitted

The FL 400 HA-G's battery indicator calibrates itself against the pack's voltage curve during the first calibration cycle — not at power-on. When a new Ni-MH pack goes in, the instrument has no reference for the new cells and defaults to a conservative threshold. This produces a false low-battery warning even on a fully charged pack. Running the calibration routine through the instrument menu clears this immediately. Until that cycle completes, the indicator reading is not meaningful.

FL 400 HA-G shuts off during grade alignment after sitting unused in a case

Ni-MH cells self-discharge at roughly 1–2% per day at room temperature. After several weeks in a carry case, the pack voltage can drop below the BMS recovery threshold — typically around 2.0V for a two-cell pack. At that point the instrument powers on briefly, draws current for the grade alignment sequence, and the BMS cuts output before the motor reaches speed. Slow-charge the pack at the instrument's standard charge rate for a full cycle first, confirming the terminal voltage reaches at least 2.6V before attempting a measurement session.

Compatible Models

Rotationslaser FL 400 HA-G FL 400 HA-G

Replaces Part Numbers

10-05506 GF-243000-18

Technical Specifications

Voltage2.4V
Amp Hours8000mAh
Capacity8000mAh
Rate19.2Wh
Net Weight282.8g /9.98 oz
Gross Weight462.8g /16.32 oz
Approximate Weight462.8g /16.32 oz
Dimension 121.10 x 34.80 x 33.00mm

Product Highlights

  • Brand: Geo-Fennel
  • 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 FL 400 HA-G powers on fine but cuts out the moment the rotation head starts spinning — is this the battery?

Yes, and it's a specific failure mode. The motor-start surge draws a short high-current spike that a degraded or deeply discharged Ni-MH pack cannot sustain — the BMS cuts output to protect the cells. Slow-charge the pack for a full cycle, then confirm terminal voltage is at or above 2.6V before power-on. If the cutout stops after a full charge, the pack was voltage-depleted, not failed.

The FL 400 HA-G won't charge after the battery sat in storage for months — charger shows no activity.

A Ni-MH pack left uncharged for months can drop below the charger's minimum detection voltage, typically around 1.8V per cell. The charger sees the pack as absent or faulted and does nothing. Connect the pack to the charger and leave it for 20–30 minutes — some chargers apply a trickle pre-charge pulse below the detection threshold that brings the cells back into range. If the charger then begins a normal charge cycle and terminal voltage climbs past 2.2V, the pack has recovered and will accept a full charge.

Laser readings on the FL 400 HA-G start drifting or resetting mid-session even though the battery indicator shows charge remaining.

This is a voltage-dropout issue under sustained load, not a capacity problem. As the Ni-MH cells age, internal resistance rises — the pack holds a resting voltage that looks acceptable, but sags under the combined draw of the motor, laser diode, and electronics during active measurement. The instrument's processor detects the voltage drop and resets to protect calibration integrity. Measure the pack's terminal voltage under load with a multimeter: if it falls below 2.0V during operation, the cells have degraded and the pack needs replacing.

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