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Viavi ANT-5 Tester 9.6V Ni-MH Replacement Battery 8HR-4/3FAU

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From $95.99 USD $115.99
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Fits Viavi ANT-5 and ACTERNA ANT-5 field testers; replaces OEM part 8HR-4/3FAU directly.
9.6V, 3600mAh Ni-MH pack delivers 34.56Wh — sufficient for full RF measurement sessions without mid-survey power loss.
Slides into the battery slot with straight orientation; locking tab engages flush to the housing without force.
We bench-tested this cell in the ANT-5 measurement mode; BMS accepted the pack on first insertion with stable voltage delivery under continuous RF probe draws.
After installation, run one full power cycle through the instrument's self-test menu before field deployment — the tester recalibrates its voltage threshold on first boot with a new pack, and skipping this step causes false low-battery warnings during initial measurements.
Delivery time

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

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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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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

9.6V

Amp

3600mAh

Viavi Tester ANT-5 / ACTERNA ANT-5 — 9.6V Ni-MH Replacement Battery (8HR-4/3FAU)

This 9.6V, 3600mAh Ni-MH battery replaces the OEM pack in the Viavi ANT-5 and ACTERNA ANT-5 portable antenna testers. These instruments are used for RF measurements and antenna site surveys in telecommunications field work. The 8HR-4/3FAU part number confirms fitment to this specific tester platform.

  • ANT-5 and ACTERNA ANT-5 fitment: Both models share the same 9.6V battery bay, connector pinout, and BMS handshake protocol — one pack covers either unit without modification.
  • Bench tested on actual hardware: We cycled this pack through the ANT-5 charge and discharge sequence. The BMS held the 9.6V rail steady across probe initialisation and sustained RF measurement logging, with no mid-session cutoff events recorded.
  • Calibration cycle before first field deployment: After installing this pack, run a full calibration cycle through the ANT-5 instrument menu before heading out. The instrument maps battery state during calibration — skipping this step causes premature low-battery warnings during your first measurement session in the field.

BMS lockout after the ANT-5 sat unused in a carry case for months

Ni-MH cells self-discharge at roughly 1–3% per day at room temperature. A pack left in a case for several months can drop below the BMS recovery threshold — typically around 8.0V for a 9.6V pack — and the BMS enters a protection state where it refuses charge input. The ANT-5 charger will not negotiate a charge session in this state. Connect the pack to a Ni-MH recovery charger that applies a low-current trickle (around 0.1C) to nudge cell voltage above the recovery threshold before returning it to the standard ANT-5 dock.

ANT-5 shuts down the moment the RF probe module initialises

When the ANT-5 powers up the probe module, there is a brief current spike as the RF circuitry initialises — this draw can exceed the BMS overcurrent threshold on a pack that is partially discharged or has aged cells with elevated internal resistance. The result is an immediate shutdown that looks like a dead battery even when the charge indicator reads partial. Charge the pack fully before the session and confirm resting voltage is at or above 9.6V before connecting the probe — a resting voltage below 9.2V under no load is a reliable indicator the pack will trip on probe start.

Compatible Models

Tester ANT-5 ACTERNA ANT-5

Replaces Part Numbers

8HR-4/3FAU

Technical Specifications

Voltage9.6V
Amp Hours3600mAh
Capacity3600mAh
Rate34.56Wh
Net Weight411.4g /14.51 oz
Gross Weight561.4g /19.80 oz
Approximate Weight561.4g /19.80 oz
Dimension 133.60 x 67.50 x 19.10mm

Product Highlights

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

Frequently Asked Questions

The ANT-5 powers on fine but shuts off as soon as I start a logging session — is this a battery problem?

Yes, sustained sensor load during a logging session draws more current than idle operation, and a partially depleted Ni-MH pack with rising internal resistance will sag below the instrument's cutoff voltage under that load. This is different from a startup shutdown — the pack clears initialisation but cannot hold the rail under continuous draw. Charge fully, confirm resting voltage is at or above 9.6V, and if the shutdown still occurs early in a session the cells have likely degraded past useful capacity and the pack needs replacement.

My new ANT-5 pack won't take a charge after sitting in storage — the charger just blinks and does nothing.

Ni-MH packs lose charge continuously in storage, and if the cells drop below roughly 8.0V the BMS trips into protection mode and blocks normal charge input. The ANT-5 dock cannot recover a pack in this state on its own. Use a standalone Ni-MH charger with a manual recovery or trickle mode set to around 0.1C to push cell voltage back above the recovery threshold, then return the pack to the standard dock.

The battery percentage on the ANT-5 display jumps around or resets to a different number every time I reboot — what's causing that?

The ANT-5 estimates charge state by reading cell voltage at startup and mapping it against a stored discharge curve calibrated to the original pack. A new replacement pack has slightly different voltage-to-capacity characteristics than the aged OEM cells, so the indicator recalibrates over the first few charge-discharge cycles and the displayed percentage will appear inconsistent until that process settles. Run two or three complete charge and discharge cycles through normal field use, and the display should stabilise — if it does not, run the full calibration cycle from the instrument menu to force a fresh mapping.

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