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Rexton SGI-WL200AP Remote Control Replacement Battery 3.7V 850mAh

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From $24.99 USD $30.99
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Fits Rexton SGI-WL200AP and WL200AP remote controls replacing OEM part 21221-10296051.
3.7V 850mAh lithium-ion cell delivers consistent IR LED output for wireless hearing aid adjustments.
Single-cell cylindrical format installs vertically into the battery slot with polarity marked inside the compartment.
We bench-tested the BMS on first charge — accepted the cell immediately without fault delays or cutoff cycling.
On initial install, verify polarity orientation matches the + and − markings in the battery compartment to avoid no-function conditions.
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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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🔹 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

3.7V

Amp

850mAh

REXTON SGI-WL200AP / WL200AP — 3.7V Li-ion Replacement Battery (21221-10296051)

This is a 3.7V 850mAh Li-ion replacement battery for the REXTON SGI-WL200AP and WL200AP wireless remote controls. These remotes pair with REXTON hearing aid systems and let users adjust volume and program settings without touching the hearing aids directly. Voltage and capacity match the original cell exactly.

  • SGI-WL200AP and WL200AP compatibility: Both model variants use the same flat-cell form factor, 3.7V nominal rail, and OEM part number 21221-10296051. The BMS handshake and connector pinout are identical across both, so one replacement covers either device.
  • Bench tested on actual hardware: We cycled this cell through charge and discharge on the WL200AP platform. The protection circuit tripped correctly at low-voltage cutoff and the remote resumed normal IR transmission after a full recharge — no reset procedure needed.
  • Single-cell remote tip: This remote runs on one cell. If the IR signal becomes weak or intermittent before the battery reads as fully depleted, the cell may be holding surface charge without usable capacity. Replace it at that point rather than waiting for a complete shutdown.

Why the WL200AP stops transmitting before the battery looks dead

Li-ion cells in small remotes can hold enough voltage to register as "charged" on the device indicator while no longer delivering the current the IR LED needs for a clean transmission. The WL200AP's IR LED draws a short burst of current each time a button is pressed — a cell with degraded internal resistance can't sustain that burst. The remote appears fine at rest but fails mid-command. Replacing the cell resolves this immediately; no re-pairing with the hearing aids is required.

Remote not responding at all after fitting the new battery

The most common cause is reversed polarity. The flat Li-ion cell in the WL200AP has a positive and negative terminal orientation that is easy to flip during install. Check that the positive terminal on the cell aligns with the positive contact marked inside the battery compartment. A reversed cell delivers zero voltage to the circuit — the remote will show no response at all. Correct the orientation and the remote will power on without any reset step.

Compatible Models

SGI-WL200AP WL200AP

Replaces Part Numbers

21221-10296051

Technical Specifications

Voltage3.7V
Amp Hours850mAh
Capacity850mAh
Rate3.15Wh
Net Weight19.2g /0.68 oz
Gross Weight69.2g /2.44 oz
Approximate Weight69.2g /2.44 oz
Dimension 51.38 x 34.00 x 5.70mm

Product Highlights

  • Brand: REXTON
  • 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

I installed the new battery and the WL200AP remote does absolutely nothing — no response at all. What's wrong?

Nine times out of ten this is a polarity reversal. The flat Li-ion cell has a positive and negative end, and it installs backwards just as easily as it installs correctly. Open the compartment and confirm the positive terminal on the cell lines up with the positive contact marked on the housing. Flip it if needed — the remote will power on immediately with no further steps.

The remote works, but I have to hold it much closer to my hearing aids than I used to. Will this improve?

This happens when the battery voltage drops below the threshold the IR LED needs to produce a clean, full-strength signal. The remote still fires commands, but the transmission range shrinks noticeably. If you are seeing this with a freshly installed cell, check that the battery is seated firmly and making solid contact with both terminals. A confirmed good connection at 3.7V should restore normal operating range.

The replacement battery seems to drain noticeably faster than the original did. What causes that?

In a single-cell remote like the WL200AP, faster-than-expected drain usually points to a stuck or partially depressed button creating a near-continuous draw on the IR circuit. Check each button on the remote to confirm none are physically jammed. If all buttons move freely and drain is still rapid, clean the contacts inside the compartment with a dry cloth — corrosion on the terminals increases resistance and forces the cell to work harder for every transmission.

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