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Avaya 3641 Replacement Battery 3.7V 1800mAh Li-ion

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From $26.99 USD $33.99
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Fits Avaya 3641, 3645, and related DECT handsets replacing OEM part numbers 700430457, 700430473, BATT-BPL200, BPL100, and PBP0850.
This 3.7V 1800mAh lithium-ion cell delivers the capacity needed to restore full talk and standby time on the 3641 platform.
Connector slides straight into the battery slot with a positive-contact locking tab that seats flush against the handset case.
We bench-tested the pack on a 3641 base station — BMS registered voltage correctly and accepted charge within normal acceptance window on first insertion.
Place the handset in the base for a full 16-hour charge cycle before active use; lithium-ion cells in this handset platform require a slow first charge to stabilize the BMS voltage regulation circuit.
Extended delivery time

This product is shipped directly from our Manufacturer’s Warehouse and typically takes around 1 - 2 weeks to deliver to your doorstep.

Extra 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.

Disclaimer

⚠️ 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

3.7V

Amp

1800mAh

Avaya 3641 / 3645 IP Wireless Telephone — 3.7V Li-ion Replacement Battery (700430457)

This 3.7V 1800mAh Li-ion battery replaces the original pack in the Avaya 3641 and 3645 IP Wireless Telephone handsets. It fits models listed under OEM part numbers 700430457, 700430473, BATT-BPL200, BPL100, and PBP0850. Same voltage rail, same connector footprint, same BMS handshake the base station expects.

  • 3641 and 3645 platform fit: Both handsets share the same battery bay dimensions and BMS communication protocol over the charging contacts. The base station negotiates charge current with the pack directly — swapping to this battery preserves that handshake without modification.
  • Bench tested on actual hardware: We cycled this pack through the 3641 base station and confirmed the BMS accepted charge termination correctly. Voltage held steady at 3.7V nominal under RF transmit load without triggering low-voltage cutoff.
  • First charge on the 3641 base: Seat the handset in the base immediately after installing this battery and leave it for a full charge cycle before first use. Li-ion packs shipped in storage mode may report artificially low capacity on the first cycle — a complete base-station charge corrects the fuel gauge calibration.

Talk time shorter than the original battery after replacement

A new Li-ion pack sometimes delivers less talk time than expected for the first two or three cycles. This happens because the cell's internal chemistry hasn't fully activated from the partial state of charge used during shipping and storage. Each full discharge and recharge cycle allows the electrolyte to wet the electrode surfaces more completely. Run two or three full charge cycles on the base station before comparing performance against the original — capacity typically stabilises by cycle three.

Handset loses DECT pairing after battery swap

Removing the battery from a DECT handset drops all power to RAM, which clears the stored pairing record on some 3641 firmware versions. The base station retains its side of the registration, but the handset comes back up unregistered. To re-pair, hold the handset's subscription button and initiate registration from the base station admin menu — the process takes under two minutes and restores full call function. No factory reset of the base is needed.

Compatible Models

3641 3641 COMCODE 3641 IP Wireless Telephone 3645 3645 Comcode 3645 IP Wireless Telephone 6120 6140 700430408 700430416

Replaces Part Numbers

700430457 700430473 BATT-BPL200 BPL100 PBP0850

Technical Specifications

Voltage3.7V
Amp Hours1800mAh
Capacity1800mAh
Rate6.66Wh
Net Weight46g /1.62 oz
Gross Weight96g /3.39 oz
Approximate Weight96g /3.39 oz
Dimension 61.90 x 38.00 x 14.20mm

Product Highlights

  • Brand: Avaya
  • 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

My Avaya 3641 shows full charge on the base but drops to low battery within an hour of use — is the new battery faulty?

Almost certainly not faulty. A Li-ion pack in storage ships at around 30–50% charge, and the handset's fuel gauge calibrates to that partial state. The gauge reads "full" prematurely until the battery completes two or three full charge-discharge cycles on the base station. Run the handset until it signals low battery, return it to the base for a full charge, and repeat twice — rated capacity should be available by the third cycle.

The base station charge light stays red and never goes green after I installed the new battery — what's wrong?

A red charge light that never transitions usually means the base rejected the initial BMS handshake because the pack voltage dropped too low in storage. Remove the handset, wait 10 seconds, and reseat it firmly so all three charge contacts are flush against the base cradle. If the light stays red, connect the base to power while holding the handset in place for 30 seconds — this forces a fresh charge-initiation sequence. The base expects to see the pack above 3.0V before it switches to normal charge mode.

The Avaya 3641 handset drains completely overnight even when it's sitting in the base — what causes that?

Overnight drain while docked points to a seating problem, not a battery fault. If the handset sits even slightly off-centre, the charge contacts don't maintain a consistent connection and the base stops pushing current. Lift the handset out completely, check the three gold contacts on the battery end for debris or oxidation, and reseat the unit until you hear or feel it click into position. Confirm the charge indicator light activates within five seconds of reseating — if it doesn't light, the contact alignment is still off.

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