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JDSU 21108524 7.4V 6800mAh Li-ion Replacement Battery

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From $58.99 USD $72.99
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Fits JDSU model 21129596 000 and 21100729 000 optical test instruments, replacing OEM part number 21108524.
7.4V 6800mAh lithium-ion pack delivers sustained voltage for extended field measurement sessions without mid-test shutdowns.
Connector seats flush into the battery compartment with a positive-side contact locking tab; verify orientation before seating.
We bench-tested this cell in a 21129596 unit running continuous fiber attenuation measurements—BMS held stable under sensor load, no early cutoff.
After installing, run a full calibration cycle through the instrument menu before field deployment; the unit maps battery state during this cycle and skipping it triggers premature low-battery warnings on first measurement sessions.
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

6800mAh

JDSU WiFi Advisor / Viavi SC-TPS — 7.4V Li-ion Replacement Battery (21108524)

This 7.4V 6800mAh Li-ion pack replaces OEM part 21108524 in JDSU and Viavi field test instruments, including the WiFi Advisor Wireless LAN Analyzer, SC-TPS, and units carrying model numbers 21129596 000 and 21100729 000. These are handheld optical and wireless test platforms used in active fiber and LAN network diagnostics. Capacity is 6800mAh (50.32Wh).

  • Cross-model fit — 21129596 000, 21100729 000, WiFi Advisor, SC-TPS: These units share the same battery bay geometry, 7.4V power rail, and BMS handshake protocol. One pack covers all four fit models without modification.
  • Bench tested on actual hardware: We cycled this pack under sustained RF scanning and optical measurement loads. The BMS held voltage within spec through probe initialisation spikes and maintained stable output across logging sessions without tripping cutoff.
  • Post-install calibration cycle: After fitting this pack, run a full calibration cycle through the instrument menu before deploying to the field. The instrument maps battery state during that routine — skipping it causes the low-battery indicator to fire prematurely on your first measurement session.

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

Li-ion cells self-discharge over storage. If the pack drops below roughly 2.5V per cell while sitting idle, the BMS trips a deep-discharge lockout and the instrument will not power on — even on charge. The fix is to connect the charger and leave it for at least 30–60 minutes before attempting to power the unit. Most BMS circuits include a trickle-recovery mode that brings cells back up to the minimum threshold before allowing full charge current.

Readings resetting or dropping out mid-logging session

This is a voltage dropout issue, not a capacity issue. Sustained sensor or RF loads pull higher current than the standby draw the instrument was calibrated against, causing momentary voltage sag that the instrument interprets as a low-battery condition. A worn or partially degraded cell shows this much earlier in the charge cycle. Replacing the pack and running the calibration cycle through the instrument menu resolves the threshold mismatch — confirm cell voltage reads above 7.0V under load before deployment.

Compatible Models

21129596 000 21100729 000 WiFi Advisor Wireless LAN Analyzer Viavi SC-TPS

Replaces Part Numbers

21108524

Technical Specifications

Voltage7.4V
Amp Hours6800mAh
Capacity6800mAh
Rate50.32Wh
Net Weight195g /6.88 oz
Gross Weight265g /9.35 oz
Approximate Weight265g /9.35 oz
Dimension 73.60 x 71.10 x 19.20mm

Product Highlights

  • Brand: JDSU
  • 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

The instrument powers on fine but shuts off the moment I start a USB data transfer to the PC — why?

USB transfer adds a second simultaneous current draw on top of the active measurement load. If the cell is aged or the BMS threshold is set conservatively, that combined draw causes a voltage dip that triggers cutoff. We saw this during bench testing — a fresh pack at full charge holds voltage through the combined load without tripping. Fit the replacement pack, run the instrument's calibration cycle, then retry the transfer.

My JDSU tester won't charge at all after sitting in the van for several months — is the battery dead?

Not necessarily. When a Li-ion pack self-discharges below the BMS recovery floor (around 5.0V total for a 7.4V two-cell pack), the protection circuit blocks charge input entirely. Connect the charger and leave it undisturbed for 45–60 minutes — most BMS circuits will trickle current into the cells until they recover enough voltage to accept a normal charge rate. If the charge LED still shows nothing after an hour, check charger output voltage at the connector — it should read between 8.2V and 8.4V.

The battery percentage on my WiFi Advisor jumps around at startup — shows 80%, then drops to 40% after one screen refresh. What's causing that?

The instrument's fuel gauge recalibrates its voltage-to-percentage table against the cell it last used. A new pack has a slightly different discharge curve, so the first few power cycles produce inconsistent readings while the instrument re-maps the thresholds. Run two full charge-and-use cycles without interrupting them early. After the second cycle the percentage display stabilises and tracks accurately through the rest of the charge curve.

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JDSU 21129596 000 Replacement Battery, 7.4V, 6800mAh, Li-ion 1

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