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Ascom Myco Replacement Battery 3.7V 1750mAh Li-ion

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From $31.99 USD $39.99
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Fits Ascom Myco, Myco SH1 VoWiFi, and SH1-ABAA handsets; replaces OEM part 490926A and RB-490926-LW.
3.7V, 1750mAh lithium-ion cell delivers full handset runtime across hospital floors and clinical zones.
Flat connector seats into the battery slot with a single locking tab; no polarity risk on insertion.
We bench-tested this cell in the Myco charge cradle; BMS accepted the new chemistry on first cycle without fault codes.
After installation, let the device complete its power-on self-test without interruption — medical handsets verify BMS chemistry at startup, and stopping this cycle triggers a false battery fault until full reboot.
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.

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

1750mAh

Ascom Myco SH1 Series — 3.7V Li-ion Replacement Battery (490926A)

This is a 3.7V, 1750mAh Li-ion battery for the Ascom Myco wireless handset. It fits the Myco, Myco SH1 VoWiFi, SH1-ABAA, and SH1-ABAA/F models used in hospital and clinical communication systems. Also cross-references OEM part RB-490926-LW.

  • Myco SH1 platform compatibility: The SH1-ABAA and SH1-ABAA/F share the same 3.7V battery bay, connector pinout, and BMS handshake protocol. One cell fits all four model variants without modification.
  • Bench tested on actual hardware: We cycled this cell through charge and discharge on an SH1 handset. The BMS accepted the cell on first insertion, completed voltage verification, and held the charge curve within the expected range for Li-ion at this capacity.
  • Post-swap self-test protocol: After installing this battery, let the Myco complete its full power-on self-test without pressing any keys or interrupting the boot sequence. The BMS runs a chemistry verification step at startup. Interrupting it logs a false battery fault that persists until the next full reboot.

Why the Myco alarms low battery immediately after a confirmed full charge

The Myco's BMS stores learned thresholds calibrated to the original cell's charge curve. A new cell with a slightly different internal resistance profile can read below the BMS alarm threshold on the first cycle, even at full charge. This is not a fault with the replacement cell. Run one complete charge-discharge cycle and the BMS recalibrates its reference points. The low-battery alarm clears after that first full cycle completes.

Myco handset will not power on after the battery sat in storage

Li-ion cells self-discharge over time. If this battery was stored for several months before installation, its resting voltage may have dropped below the Myco's BMS recovery threshold — typically around 2.5V for this chemistry. The handset will not attempt to boot below that threshold as a protection measure. Place the handset on charge for at least 30 minutes before pressing the power button, giving the charge IC enough time to bring the cell above the minimum recovery voltage before the BMS re-enables the output rail.

Compatible Models

Myco Myco SH1 VoWiFi SH1-ABAA SH1-ABAA/F

Replaces Part Numbers

490926A RB-490926-LW

Technical Specifications

Voltage3.7V
Amp Hours1750mAh
Capacity1750mAh
Rate6.48Wh
Net Weight38g /1.34 oz
Gross Weight63g /2.22 oz
Approximate Weight63g /2.22 oz
Dimension 53.50 x 51.40 x 6.80 mm

Product Highlights

  • Brand: Ascom
  • 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 Myco shows a low battery warning straight after I charged it overnight — is the new battery faulty?

It is not faulty. The Myco's BMS uses a learned voltage profile from the original cell, and a new cell's internal resistance reads slightly differently on the first cycle. The alarm threshold check fails until the BMS recalibrates. Run one full charge-discharge cycle — charge to 100%, use the handset until it powers off from low battery, then charge fully again. The warning clears after that cycle completes.

The Myco handset shuts off unexpectedly during calls in the first week of use — what is causing this?

In the first 10 charge cycles, a new Li-ion cell has not yet reached its full electrochemical capacity. The Myco's load profile during active calls draws more current than standby, and the cell voltage sags under that load faster than it will once the cell is broken in. The BMS reads the sag as a low-voltage cutoff condition and shuts the device down as a protection measure. Continue normal use through the first 10 full cycles and the sag reduces as the cell conditions.

The charge indicator on the Myco is stuck below 100% after several hours on the charger — should I be concerned?

The Myco's charge IC applies a conservative current limit when it detects a new or recently depleted cell, which extends the final topping-off phase. The indicator may sit at 90–95% for longer than expected on the first charge. Leave the handset on the cradle for a full uninterrupted charge session — do not remove it when the indicator appears close to full. After the first complete charge cycle, the IC adjusts and subsequent charges reach 100% in the normal timeframe.

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