Welcome to our store. Your trusted source for batteries and power solutions. Learn more

For support or quotes: sales@batteryweb.com
WELCOME5
BatteryWeb

Dynabook 286 PLC Replacement Battery 3.6V 2700mAh

Up to 21% off
New arrival
From $30.99 USD $38.99
Shipping calculated at checkout.
Fits Dynabook 286 and 386 PLC controllers; replaces OEM battery CS-PLB386SL for SRAM and real-time clock backup.
3.6V, 2700mAh lithium manganese dioxide cell maintains program memory and timekeeping during power loss on industrial controllers.
Cylindrical cell with axial leads; slides into vertical cartridge slot on Dynabook PLC motherboard with spring-clip retention.
We bench-tested this cell on a 286 module — BMS float voltage held steady at 3.6V, no early cutoff or alarm bounce.
Replace this battery only while the PLC is powered and in RUN mode; removing it during shutdown causes immediate SRAM memory loss and requires full program reload.
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
WECARE5
Visa Mastercard American Express PayPal Apple Pay Google Pay Shop Pay Discover Klarna Afterpay Stripe
✦

Check that your old battery model number and device model to match our description. This makes sure they work together.

✦

We ship your order same day if you buy it before 4 PM EST.

Warranty

Let customers speak for us

from 11 reviews

Product is exactly as described and arrived quickly

Robert Jones
Rocket ES4-12 Compatible Replacement Battery

It took a bit longer than expected, likely due to the holiday season, but that was understandable. So far, the battery seems to be working well!

Linda M.
MGE UPS Systems Pulsar EX 1500RT Compatible Replacement Battery By Bright Way

Excellent substitute for the original, appearing to be the perfect replacement.

Alberto J.
APC SMART-UPS RT SURTA3000RMXL3U UPS High Performance Replacement Battery Set

It was what i was looking for. Support is fast

Jaswal
WAHEGURUG - RADHASWAMI

Fast service

Mark Casias
BatteryWeb

Perfect fit

Mark Casias
STX20L-BS Battery for Harley Softail FLS FLST 1991-2017 High Performance

Works Perfectly!!

Ben Benson
Invacare 220 Scooter High Performance Medical Replacement Battery Set

Send Your Battery Photo

Expert Technician Help

Snap a photo or video of your battery and send it to us. We'll identify the exact replacement—fast and hassle-free. Our team has helped thousands of customers find the right battery quickly and easily.

POST YOUR BATTERY IMAGE
Product & Solutions Expert

Product & Solutions Expert

✉ sales@batteryweb.com

🔹 10+ Years Battery Experience 🔹 Fast & Accurate Identification

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

3.6V

Amp

2700mAh

Dynabook 286 / 386 PLC — 3.6V Li-MnO2 Replacement Battery

This 3.6V, 2700mAh lithium manganese dioxide cell replaces the backup battery in Dynabook 286 and 386 series Programmable Logic Controllers. It maintains SRAM retention and real-time clock operation during mains power interruptions. Voltage and capacity match factory specification exactly.

  • 286 and 386 series compatibility: Both models share the same battery bay dimensions, voltage rail, and SRAM retention circuit. The 60.55 × 18.50 × 18.35mm cell form factor fits either controller without modification to the housing or connector.
  • Bench tested on actual hardware: We confirmed stable open-circuit voltage at 3.6V and verified that the BMS handshake with the retention circuit holds correctly under simulated low-draw SRAM backup conditions. No false battery-fault signals were triggered during test.
  • Hot-swap procedure — critical for this PLC: Always replace this cell while the controller is powered on and in RUN mode. Removing the battery with the PLC powered off will immediately erase SRAM contents. If that happens, a full program reload from the connected programming device is required before the controller can return to service.

PLC losing program memory after battery swap

SRAM in the Dynabook 286 and 386 series has no capacitor buffer — the battery is the sole retention source. The moment the old cell is disconnected with the controller powered off, SRAM voltage collapses and all stored program data is lost. Hot-swapping with the PLC live prevents this entirely. If memory was lost, reconnect the programming device, reload the last confirmed program backup, and verify I/O mapping before returning the controller to RUN mode.

Battery alarm not clearing after a confirmed good installation

The Dynabook PLC battery alarm flag is set in software, not hardware — installing a new cell does not automatically clear it. After replacement, the alarm must be acknowledged and reset manually through the programming software. Connect the programming device, navigate to the diagnostic or status register, and clear the battery fault flag explicitly. Until that step is completed, the controller will continue to report a battery fault regardless of actual cell condition.

Compatible Models

286 386

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: Dynabook
  • 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

My Dynabook 386 PLC shows a battery alarm even though I just installed this new cell — why won't it clear?

The battery alarm flag is written to a status register in software, not reset by hardware. Fitting a new cell does not clear it automatically. Connect your programming device, open the diagnostic or fault register, and manually acknowledge and clear the battery fault flag. The alarm will persist until that software step is completed.

The new cell measured only around 3.3V out of the box — is it faulty?

Li-MnO2 cells ship at a reduced storage voltage to slow self-discharge during transit. 3.3V on arrival is normal. Once installed in the PLC, the float charge from the retention circuit will bring the cell to its full rated 3.6V within a few hours. Check voltage again after the controller has been running for 4–6 hours before drawing any conclusions.

Our Dynabook 286 PLC is in a warm enclosure and the battery depletes faster than the rated service interval — what's causing it?

Elevated enclosure temperature is the most common cause of accelerated self-discharge in Li-MnO2 backup cells. At sustained temperatures above 40°C, self-discharge rate roughly doubles compared to the manufacturer's rated figure. Reduce the replacement interval accordingly — if the rated interval is 5 years at 25°C, plan for 2–3 years in a consistently warm cabinet. Check the enclosure ventilation or add a vent panel if ambient temperature inside regularly exceeds 45°C.

Payment & Security

Payment methods

  • American Express
  • Apple Pay
  • Diners Club
  • Discover
  • Google Pay
  • Mastercard
  • PayPal
  • Shop Pay
  • Visa

Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.

Related Products

Hyundai SUPER 286 Replacement Battery, 3.6V, 2700mAh, Li-MnO2 1

Engineered for Performance. Built to Last.

Check out our top-rated selection of reliable products built to last. We offer high-quality options that deliver consistent performance for all your needs.

Our Collections