Symbol MC3100 2.4V CMOS Backup Battery 20mAh Ni-MH
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Symbol MC3100 2.4V CMOS Backup Battery 20mAh Ni-MH - is backordered and will ship as soon as it is back in stock.
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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.
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Disclaimer
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Symbol MC3100 2.4V CMOS Backup Battery 20mAh Ni-MH - is backordered and will ship as soon as it is back in stock.
Voltage
2.4V
Amp
20mAh
Symbol MC3100 / MC3190 Series — 2.4V Ni-MH CMOS Backup Battery
This 2.4V, 20mAh Ni-MH cell is the internal CMOS backup battery for the Symbol MC3100 and MC3190 series handheld barcode scanners. It holds the real-time clock and SRAM configuration data when main power is removed or the primary battery is swapped. Without a functional backup cell, the unit loses its date, time, and stored settings on every power cycle.
- MC3100 and MC3190 platform coverage: Both the MC3100 and MC3190 share the same CMOS backup circuit and connector footprint. The cell sits on a retention rail separate from the main Li-ion pack — same voltage requirement, same BMS handshake, same physical form factor across the full product family.
- Bench tested on actual hardware: We seated this cell in an MC3190 chassis and pulled the main battery. The RTC held its timestamp and the configuration SRAM retained all stored settings across the power gap. The retention circuit held stable above the 2.8V minimum threshold throughout the test.
- Post-install RTC correction: After fitting this cell, boot the MC3100 and manually set the correct date and time through the system settings. The CMOS circuit powers the RTC, and any interruption during the swap resets the clock to its default value — that default will not correct itself automatically.
Clock resetting to a default date after every MC3100 power cycle
The RTC on the MC3100 draws continuous low current from the CMOS backup cell, even when the unit is off. As the Ni-MH cell ages, its terminal voltage drops below the 2.8V minimum retention threshold. Once that floor is breached, the RTC loses its reference and reverts to the factory default timestamp on the next boot. Replacing the backup cell restores the retention voltage and stops the clock reset loop.
MC3100 losing scanner configuration every time the main battery is removed
The MC3100 stores active scanner profiles and network parameters in SRAM. That SRAM is backed exclusively by the CMOS cell during main battery swaps — if the backup cell is depleted, SRAM loses power and the data is gone. This is different from a clock reset: the unit may boot with the correct time but still show a blank or default scanner profile. Check the backup cell voltage first — a healthy cell reads at or above 2.8V under light load.
Compatible Models
Technical Specifications
Product Highlights
- Brand: Symbol
- Manufacturer: CS
- Series: Standard
- Color: Green
- Product Type: Ni-MH
- Battery Type: Ni-MH
- Warranty: 12 Months
- Bulk Orders: sales@batteryweb.com
Frequently Asked Questions
My MC3100 shows the right time after I set it, but every time I pull the main battery the scanner profiles are gone — why?
The SRAM that holds scanner configuration is powered by the CMOS backup cell during main battery removal, just like the RTC — but the two circuits draw at different rates. A partially degraded cell may hold enough charge to keep the clock running but not enough to sustain SRAM through a swap. Replace the backup cell and confirm it reads at or above 2.8V before reassembling.
I fitted a new CMOS backup cell in the MC3190 but the unit is still flagging a CMOS checksum error on boot — what's wrong?
A checksum error means the CMOS contents were already corrupted before the new cell was seated — the new cell alone won't rewrite the stored values. After fitting the replacement, manually re-enter the date, time, and any saved settings, then perform a clean save and reboot. The checksum recalculates from the freshly written values and the error clears on the next boot cycle.
The replacement backup cell I received measures under 2.5V on my multimeter straight out of the packaging — is it faulty?
Ni-MH cells ship at a reduced storage charge, so a lower voltage reading out of the packet is normal. Once the cell is installed and the retention circuit draws its standby current, the voltage stabilises at its operating level. Install the cell, boot the MC3100, set the date and time, and measure across the cell contacts after 10 minutes in circuit — it should read at or above 2.8V.
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