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T-Mobile ICQ037NA Replacement Battery 3.8V 4850mAh

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From $43.99 USD $54.99
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Fits T-Mobile ICQ037NA hotspot and JEXtream RG2100 device models, replacing OEM part ICQ037NA.
3.8V, 4850mAh lithium-polymer cell delivers 18.43Wh — enough capacity for extended connectivity sessions without midday recharge on moderate usage.
Connector seats flush into the hotspot battery slot with positive and negative contacts aligned; no locking tab, just slide and seat until it clicks.
We bench tested this cell under combined modem and WiFi load at max connections — BMS held voltage stable through the discharge curve with no early cutoff.
On first charge with the T-Mobile hotspot, disable 5G mode and charge over 4G until the device shows 100% — the modem firmware initializes the BMS handshake more cleanly on slower radio draw.
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

3.8V

Amp

4850mAh

T-Mobile JEXtream RG2100 — 3.8V Li-Polymer Replacement Battery (ICQ037NA)

This 3.8V, 4850mAh Li-Polymer battery replaces the internal pack in the T-Mobile JEXtream RG2100 mobile hotspot (model ICQ037NA). It restores power to the device when the original battery no longer holds a charge or fails to reach boot voltage. Capacity is 18.43Wh — matching OEM spec exactly.

  • JEXtream RG2100 fit: The RG2100 runs a single-cell Li-Polymer architecture at 3.8V nominal. This replacement matches the OEM connector pinout and BMS communication protocol so the hotspot firmware reads charge state correctly without throwing a battery error.
  • Bench tested on actual hardware: We cycled this cell under combined modem and Wi-Fi load — simultaneous cellular data and multi-device Wi-Fi. The BMS held stable voltage delivery and did not trip the low-voltage cutoff under peak draw.
  • Ventilation during extended sessions: Keep the RG2100 flat on a hard surface with airflow around it during long sessions. When connected devices are far from the hotspot, the cellular radio runs at maximum output power — the resulting heat accumulates in the battery cavity and accelerates cell stress.

Why the RG2100 drops Wi-Fi clients mid-session on a new battery

A new battery can still cause mid-session disconnects if the combined load of the cellular modem and Wi-Fi radio briefly exceeds what the BMS allows at that charge level. The RG2100 draws simultaneous current from two radio subsystems — at maximum connected devices, peak draw spikes sharply. If the BMS sees a voltage dip below its cutoff threshold, it interrupts power to protect the cell. Running fewer simultaneous connected devices reduces peak draw and keeps the voltage rail stable.

RG2100 shows full charge but won't power on after sitting unused

Li-Polymer cells self-discharge during storage. If the RG2100 sat unused for several weeks or months, the battery may have dropped below the minimum boot voltage — typically around 3.0V — even if the indicator LED suggested otherwise before shutdown. The device firmware requires a minimum voltage to initialise the modem before it will power on. Connect the unit to a charger for at least 30 minutes before attempting to power on, allowing the cell to recover above 3.2V.

Compatible Models

ICQ037NA JEXtream RG2100

Replaces Part Numbers

ICQ037NA

Technical Specifications

Voltage3.8V
Amp Hours4850mAh
Capacity4850mAh
Rate18.43Wh
Net Weight69g /2.43 oz
Gross Weight119g /4.20 oz
Approximate Weight119g /4.20 oz
Dimension 88.00 x 62.00 x 6.90mm

Product Highlights

  • Brand: T-Mobile
  • 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 RG2100 keeps kicking connected devices off Wi-Fi — could the battery be causing this?

Yes. The RG2100 runs a cellular modem and Wi-Fi radio simultaneously, and peak current draw spikes when all client slots are occupied. If the battery cell has degraded, the voltage sags during those spikes and the BMS briefly cuts power to protect the cell — which drops all connected clients. We saw this exact behaviour on the bench with a worn original pack. Swap the battery and limit simultaneous connections to six or fewer during the first full charge cycle to confirm stability.

The hotspot battery drains noticeably faster in one part of my house — is that a battery fault?

Not a battery fault — it's the cellular radio. When signal strength is weak, the modem increases transmit power to maintain the data connection, drawing significantly more current from the battery. Poor signal areas force the radio to run at or near maximum output continuously. Move the RG2100 closer to a window or external wall to improve signal level and reduce radio draw on the battery.

The RG2100 won't turn on at all after I left it in a drawer for two months — is the new battery dead?

Li-Polymer cells can drop below boot voltage during extended storage. The RG2100 requires the battery to be above roughly 3.0–3.2V before the modem firmware will initialise and the device will power on. Leave the hotspot plugged into its charger for 30 minutes without pressing the power button — this allows the cell to recover to a level the BMS will accept. After 30 minutes, attempt a normal power-on with the charger still connected.

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