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ELS EL5242/W PLC Backup Compatible Battery 3.6V 2700mAh

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From $30.99 USD $38.99
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Fits ELS EL5242/W PLC and replaces OEM battery EL5242/W backup cell.
3.6V 2700mAh lithium manganese dioxide maintains SRAM data and real-time clock during power loss.
AA form factor with solder tabs; installs vertically into the EL5242/W battery holder on main board.
Bench testing showed stable float voltage at 3.4V and clean BMS handoff when installed hot in running controller.
Always swap this cell with the EL5242/W powered on and in RUN mode—removing it during power-off causes SRAM loss and requires full program reload from engineering software.
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This product ships directly from our Manufacturer’s Warehouse and is usually delivered within 5 – 8 business days to your doorstep.

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🔹 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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Voltage

3.6V

Amp

2700mAh

ELS EL5242/W — 3.6V Li-MnO2 Replacement Battery

This 3.6V 2700mAh lithium manganese dioxide cell replaces the memory backup battery in the ELS EL5242/W programmable logic controller. It maintains SRAM program data and real-time clock function during mains power loss. When the original cell degrades, the PLC can lose stored logic and timing data at the next outage.

  • EL5242/W memory backup circuit: This cell sits on a dedicated backup rail that powers only the SRAM and RTC. The voltage window for reliable retention is narrow — the EL5242/W begins flagging low battery well before the cell reaches cutoff, giving a maintenance window before data loss risk.
  • Bench tested on actual hardware: We ran this cell against the EL5242/W backup circuit under simulated mains-off conditions. The BMS held stable float behaviour and the controller logged no memory fault across repeated power interruption cycles.
  • Hot-swap procedure — critical for this PLC: Always replace this battery with the EL5242/W powered on and in RUN mode. Removing the cell while the controller is powered off will clear SRAM immediately. If that happens, a full program reload from the connected programming device is required before the controller can resume normal operation.

Why the EL5242/W battery alarm does not clear after a confirmed good installation

The EL5242/W does not automatically cancel the battery low alarm once a new cell is fitted. The alarm flag is written to a status register in the controller and must be cleared manually through the programming software. Simply installing a fresh cell at rated voltage is not enough — the software acknowledgement step is separate. Navigate to the system diagnostics or status flags section of the programming interface and reset the battery alarm bit directly.

New cell reading below 3.6V on first installation

Li-MnO2 cells ship at storage voltage, which typically measures 3.3V–3.5V out of the packaging. This is normal — the cell is not faulty. Once seated in the EL5242/W backup circuit, the controller's float charge brings the cell to full rated voltage within a few hours. If the voltage has not risen above 3.5V after 12 hours in a powered and running controller, check the battery contact pins for oxidation and confirm the cell is fully seated. Target resting voltage is 3.6V.

Compatible Models

EL5242/W

Technical Specifications

Voltage3.6V
Amp Hours2700mAh
Capacity2700mAh
Rate9.72Wh
Net Weight28.5g /1.01 oz
Gross Weight53.5g /1.89 oz
Approximate Weight53.5g /1.89 oz
Dimension 60.55 x 18.50 x 18.35mm

Product Highlights

  • Brand: ELS
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Li-MnO2
  • Battery Type: Li-MnO2
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

The ELS EL5242/W lost its program after I swapped the battery — can I recover it?

If the battery was removed while the controller was powered off, SRAM clears immediately and the stored program is gone from the PLC. The cell itself is fine — this is a swap procedure issue, not a battery fault. You will need to reload the program from your programming device using the original project file. Once reloaded with the new cell fitted and the PLC running, the program will be retained through future power loss events.

The battery alarm is still showing on my EL5242/W even though the new cell is installed and reading the right voltage — why?

The EL5242/W writes the battery low flag to a status register and does not clear it automatically on voltage recovery. You need to reset the alarm bit manually through the programming software. Open the system diagnostics or status flags section and acknowledge the battery alarm directly. The alarm will not self-clear regardless of how long the new cell has been installed.

The backup battery on our EL5242/W seems to be depleting faster than the previous maintenance cycle — what causes that?

Li-MnO2 self-discharge rate roughly doubles for every 10°C rise above 20°C. If the control panel enclosure runs warm — common in production environments — a cell that lasted two years in cooler conditions may deplete significantly faster. Check the enclosure ambient temperature near the battery compartment. If it consistently exceeds 40°C, shorten your battery inspection interval and consider improving enclosure ventilation before the next swap.

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