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Telstra MR2100 W-10a Replacement Battery 3.7V 5040mAh

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From $33.99 USD $41.99
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Fits Telstra MR2100 and NightHawk M2 hotspots; replaces OEM part W-10a.
3.7V, 5040mAh lithium-polymer cell sustains dual Wi-Fi and cellular radio draw simultaneously.
Connector seats into the MR2100 battery slot with positive tab forward; locking tab engages.
We cycled this pack under combined modem plus eight concurrent Wi-Fi connections; BMS held stable discharge curve, no early cutoff.
On first use with poor cellular signal, the MR2100 radio pulls maximum power—keep the hotspot in a well-ventilated area to prevent thermal throttling of the battery.
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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

5040mAh

Telstra MR2100 / Netgear Nighthawk M2 — 3.7V Li-Polymer Replacement Battery (W-10a)

This is the W-10a 3.7V, 5040mAh lithium-polymer battery for the Telstra MR2100 and Netgear Nighthawk M2 mobile hotspot. It slots directly into the battery bay and restores the device's ability to run the combined cellular modem and Wi-Fi radio on a full charge cycle. Capacity is rated at 18.65Wh.

  • MR2100 and Nighthawk M2 compatibility: Both models use the same battery bay dimensions, W-10a part number, and 3.7V power rail. The BMS handshake is identical across both, so one cell covers either unit without modification.
  • Bench tested on actual hardware: We ran the cell under simultaneous cellular and Wi-Fi load at maximum connected devices. The BMS held voltage across the full discharge curve with no thermal cutoff events and no unexpected shutdown at low state-of-charge.
  • Ventilation during extended sessions: Keep the hotspot on a hard, flat surface — not a bag pocket or enclosed space — when running for long periods. The cellular radio pushes to maximum output power in low-signal areas, and heat builds quickly inside a confined space, accelerating cell stress.

Why the MR2100 drops connections mid-session under high device load

When multiple devices are connected and the hotspot is holding a busy cellular session, current draw from the combined modem and Wi-Fi radio spikes sharply. An aged or degraded cell can't sustain that draw without voltage sagging below the BMS cutoff threshold. The unit resets to protect the cell, and all connected devices lose their session. A new cell with full capacity holds the voltage rail steady through those load spikes.

MR2100 won't power on after sitting unused for several weeks

Lithium-polymer cells self-discharge during storage, and the MR2100's standby draw accelerates this further. If the cell drops below roughly 3.0V, the BMS blocks startup to prevent damage. Plug into the supplied charger and leave it for 20–30 minutes before attempting to power on — most BMS circuits will begin a recovery charge cycle at that point and restore boot voltage.

Compatible Models

MR2100 NightHawk M2

Replaces Part Numbers

W-10a

Technical Specifications

Voltage3.7V
Amp Hours5040mAh
Capacity5040mAh
Rate18.65Wh
Net Weight90g /3.17 oz
Gross Weight140g /4.94 oz
Approximate Weight140g /4.94 oz
Dimension 78.70 x 62.40 x 9.32mm

Product Highlights

  • Brand: Telstra
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Li-Polymer
  • Battery Type: Li-Polymer
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My MR2100 keeps disconnecting everyone on it even though the battery shows half charge — what's happening?

The charge indicator reads state-of-charge, not the cell's ability to deliver current. Under combined modem and Wi-Fi load at maximum connections, a degraded cell voltage-sags below the BMS cutoff even at 50% indicated charge, triggering a reset. A new 5040mAh cell sustains the current draw without the voltage drop. Check that the hotspot is also not sitting in an enclosed space — heat compounds the sag.

The battery drains noticeably faster when I'm in a weak signal area — is that the battery or the device?

That's the device, not a faulty cell. The cellular radio scales transmit power up to maximum when signal is poor, which is the single largest current draw in the MR2100. Add multiple connected devices on top and total draw can approach two to three times what it would be in strong signal. Moving to a window or elevated location with better reception reduces radio output power and extends time between charges.

The hotspot gets quite warm during long sessions — will that damage the new battery?

Sustained heat above around 45°C accelerates lithium-polymer cell degradation over time. The MR2100 generates most of that heat from the cellular modem, not the battery itself. Place the unit on an open surface rather than inside a bag or drawer during extended use, and avoid direct sunlight. If the unit feels hot to the touch, a short rest with the screen off lets both the modem and cell temperature drop back to a safe range.

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