Motorola CP040 MNN4254AR Replacement Battery 7.5V 1800mAh
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Motorola CP040 MNN4254AR Replacement Battery 7.5V 1800mAh - is backordered and will ship as soon as it is back in stock.
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Battery Care Tips
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
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
⚠️ 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.
Motorola CP040 MNN4254AR Replacement Battery 7.5V 1800mAh - is backordered and will ship as soon as it is back in stock.
Voltage
7.5V
Amp
1800mAh
Motorola CP040 / CP140 Series — 7.5V Li-ion Replacement Battery (MNN4254AR)
This is a 7.5V 1800mAh Li-ion battery for the Motorola CP040, CP100, CP100D, CP140, and related CP-series two-way radios. It replaces a long list of Motorola OEM part numbers including MNN4254AR, NNTN4851, PMNN4081, PMNN4082, and PMNN4251, among others. The battery uses the same connector and BMS pinout as the original pack.
- CP040 / CP100 / CP140 platform fit: These models share the same battery bay dimensions, contact strip layout, and 7.5V supply rail. The dock charger reads the BMS data line on all three, so a single pack serves the whole family without any adapter or modification.
- Bench tested on actual hardware: We cycled this pack through full charge and discharge on a CP140 test unit. The BMS accepted the dock handshake on first insertion, held voltage above 7.0V through sustained draw, and tripped overcurrent protection cleanly under a simulated high-current PTT burst — then reset without fault.
- First-insertion contact check on CP-series docks: If the dock LED flashes fault on first seating, pull the pack out, wipe the gold contact strip with a dry cloth, and reseat firmly. The CP-series dock requires a clean contact cycle to complete the BMS handshake before it will begin charging.
Why the CP040 cuts out mid-transmission on a new battery
When PTT is pressed, the transmitter pulls a short current spike — typically 1.5A to 2A on the CP040 — that the BMS must pass without tripping. A pack with weak cells or a conservative BMS threshold will cut the output rail during that spike, dropping the transmission. This battery's BMS is set to handle the full CP040 TX current without nuisance tripping. If cutouts still happen after fitting this pack, check that the radio's RF power setting is not stuck on high from a previous configuration.
Bar indicator showing one fewer bar than expected on a new pack
The CP040 uses voltage thresholds to drive its bar display — there is no fuel gauge chip. A new cell ships at storage voltage, typically around 3.7V per cell, which reads lower than a freshly charged pack. The radio sees that voltage and displays one or two bars even though the pack is not depleted. Run a full charge cycle first; once the pack reaches 8.4V at the terminals, the bar indicator will show full.
Compatible Models
Replaces Part Numbers
Technical Specifications
Product Highlights
- Brand: Motorola
- 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
My CP040 drops to low TX power partway through a shift even though the battery was fully charged at the start — what's happening?
This is voltage sag under sustained RF output. As the cells discharge, internal resistance rises, and the voltage at the radio's power amplifier drops below the threshold needed to hold full output — so the radio steps down TX power to stay within spec. It is not a fault in the battery or radio. Swap to a fresh pack mid-shift if full output power is needed throughout, or charge the current pack before the shift exceeds roughly half the battery's capacity.
The dock charger LED never stops blinking red after I insert this new battery — it has been sitting in the dock for over an hour.
A persistent red fault blink on Motorola CP-series docks usually means the pack voltage came in below the dock's acceptance threshold, or the BMS handshake did not complete. Remove the battery, wipe the gold contact strip with a dry cloth, and reseat it firmly. If the fault blink continues, charge the pack in a different known-good dock first to bring cell voltage above 7.0V — once above that threshold, your original dock will accept it.
This battery was stored unused for several months and now the radio won't turn on at all — is the pack dead?
Extended storage below around 6.0V can trigger the BMS lockout state, where the pack refuses to deliver current until a recovery charge cycle re-initialises it. A standard dock may not supply enough voltage to wake the pack from lockout. Place the pack in a Motorola IMPRES charger or a charger with a conditioning mode — these apply a low-current pre-charge to bring cell voltage back above the BMS recovery threshold, typically 6.5V, before switching to normal charge.
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