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Retevis BL48 Replacement Battery 3.7V 2400mAh Li-Polymer

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From $40.99 USD $50.99
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Fits Retevis RB48 and RB648 handheld radios, replacing OEM part number BL48 or BL648.
3.7V and 2400mAh capacity delivers full transmit power without voltage sag during sustained RF output cycles.
Gold-plated connector seats into the radio's battery slot with a positive locking tab that requires firm downward press to secure.
We bench-tested this cell in an RB48 under continuous PTT operation; the BMS accepted the pack on first insertion without dock fault signaling.
If the charger dock shows a fault LED after inserting this cell, remove the battery, wipe the gold contact strip with a dry cloth, and reseat firmly — the Retevis platform requires a clean contact cycle to accept the new BMS handshake before charging begins.
Extended delivery time

Available by SPECIAL ORDER. Delivery for this product typically takes 2 weeks.

Extra Discount: As a thank you for your patience, enjoy an extra 5% off 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

2400mAh

Retevis RB48 / RB648 — 3.7V Li-Polymer Replacement Battery (BL48 / BL648)

This 3.7V, 2400mAh Li-Polymer battery replaces the original BL48 and BL648 packs in the Retevis RB48 and RB648 handheld two-way radios. It slots into the same battery compartment as the factory pack with no modification. Capacity figure is 2400mAh / 8.88Wh as spec'd by the product data.

  • RB48 and RB648 shared platform: Both radios run the same 3.7V single-cell architecture and use an identical battery footprint, connector pitch, and BMS handshake — which is why one pack number (BL48 / BL648) covers both units.
  • Bench tested on actual hardware: We cycled the pack through transmit loads on the bench. The BMS held the output rail steady through sustained PTT presses and tripped cleanly at the low-voltage cutoff threshold without locking the pack into a fault state.
  • First insertion into the charger dock: If the dock LED flashes a fault pattern on first seating, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The RB48 dock requires a clean contact cycle to complete the BMS handshake before it will begin charging.

Why the RB48 cuts out mid-transmission on a freshly inserted battery

New Li-Polymer cells ship at storage voltage — typically around 3.6–3.75V — not at a full 4.2V charge. When you key up on the RB48, the transmit current spike can pull the cell voltage below the BMS undervoltage threshold momentarily, tripping a cutoff. This is not a fault with the pack. Charge the battery fully in the dock before first use in the field and the transmit rail will stay stable through normal PTT cycles.

Bar indicator showing one fewer bar than expected after installing the BL48

The RB48 uses simple voltage-threshold steps to drive its bar indicator — it does not count capacity. A new pack at storage voltage reads lower on those thresholds than a fully charged cell does, so the radio may show one or two bars even with a fresh battery installed. Run a full charge cycle until the dock LED goes solid green, then power the radio on. The indicator will reflect the correct voltage level at 4.1–4.2V.

Compatible Models

RB48 RB648

Replaces Part Numbers

BL48 BL648

Technical Specifications

Voltage3.7V
Amp Hours2400mAh
Capacity2400mAh
Rate8.88Wh
Net Weight40g /1.41 oz
Gross Weight65g /2.29 oz
Approximate Weight65g /2.29 oz
Dimension 59.60 x 36.20 x 9.30mm

Product Highlights

  • Brand: Retevis
  • 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 RB48 drops to low transmit power partway through a shift even though the battery was fully charged at the start — what's causing that?

Sustained RF output draws more current than standby does, and an aged or partially degraded cell can't hold the voltage rail steady under that load. The radio's power management steps down TX output to protect the BMS from hitting its undervoltage cutoff. Check the bar indicator immediately after a transmission drop — if it falls by one or two bars under PTT and recovers on standby, the cell is sagging under load. A new BL48 / BL648 pack at full charge should hold the rail above 3.6V through normal transmit cycles.

The RB48 charger dock never clears its fault LED — it just keeps blinking even after I've left the pack in overnight. What do I do?

A dock that won't clear its fault LED is usually seeing a pack voltage below its acceptance threshold — typically under 3.0V — which causes the charger to refuse to initiate a charge cycle. Remove the pack, wipe the gold contact strip with a dry cloth, and reseat it firmly to confirm the contacts are clean and fully engaged. If the LED still doesn't change, let the pack rest out of the dock for 10 minutes and reinsert — some charger circuits require a reset interval before reattempting handshake. If the dock accepts the pack after a clean reseat, let it charge to completion before powering the radio on.

My RB648 has been sitting unused for several months with the battery still installed — now the radio won't power on at all. Is the pack recoverable?

Extended storage with the battery installed drains the cell through the radio's standby current draw. If the cell drops below roughly 2.5V, the BMS enters a lockout state to prevent further discharge damage, and the radio won't respond to the power button. Seat the pack in the dock and watch the LED — if it shows any charge indicator at all (even a slow blink), the charger is recovering the cell. Leave it for a full charge cycle without interruption. If the dock shows no response whatsoever, the cell has likely dropped below the charger's recovery floor and the pack will need to be replaced.

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