Saft LM26500-M Li‑MnO2 C-Size Primary Cell

The Saft LM26500-M is a non-rechargeable, lithium‑manganese dioxide (Li‑MnO2) C-size cell built for dependable, long-duration power. It offers a stable discharge profile, low self-discharge for long shelf/standby life, and support for moderate pulse loads common in wireless and instrumentation devices.

Quick Facts

When to Choose (and When to Avoid)

• Choose if your device draws low-to-moderate average current with brief pulse bursts (e.g., radio transmissions, sensor warm-up).
• Choose if field access is difficult and you need long shelf and service life without recharging.
• Avoid if your design requires frequent high-current surges without local energy buffering—consider adding a reservoir capacitor or a different chemistry.
• Avoid if the system expects rechargeable behavior (charging or energy recovery). This is a primary cell and must not be charged.

Typical Applications

• Remote monitoring: pipeline or tank telemetry, environmental and agriculture sensors, cathodic protection monitors
• Security and safety: wireless contacts, motion/glassbreak sensors, asset trackers
• Industrial controls: PLC memory/RTC backup, valve/actuator controllers with intermittent duty
• Test and measurement: portable meters and field instruments

Integration Guidelines

Power profile and pulsed loads

• Use a bypass/reservoir capacitor close to the load (radio or actuator) to support transmit or actuation peaks and reduce voltage sag.
• Set a conservative cutoff voltage that keeps the system above its minimum operating threshold as the cell approaches end-of-life.
• Validate peak current performance at the lowest expected temperature and near end-of-discharge.

Mechanical and environmental

• Use quality C-size holders or clips with firm spring force; avoid denting the can. Protect against vibration and shock.
• Plan for operation across the expected temperature range; allow reduced pulse demands at cold start.

Protection and safety

• Do not charge. Disable or block any charge path in mixed-chemistry or universal designs.
• Provide reverse-insertion protection (mechanical keying or diode/ideal-OR) in user-serviceable products.
• Use fusing or resettable protection in accessible compartments to mitigate short-circuit risk.

Runtime Planning

Model actual duty cycle: sleep current, wake current, pulse magnitude/duration, and interval. Add temperature and pulse derating, then include a 15–25% margin for field variability. Before volume rollout, run a small pilot under real conditions to verify assumptions and set maintenance intervals.

Installation & Field Replacement

1. Power down the device if practical to avoid inrush or brownout events.
2. Inspect and clean contacts; replace worn holders to minimize contact resistance.
3. Confirm polarity; seat the cell fully with no rattle or partial insertion.
4. Perform a quick functional test (e.g., a radio ping or sensor cycle) before closing the unit.

Storage & Inventory

• Store cool, dry, and ventilated—away from heat sources and direct sun.
• Keep in original packaging to protect terminals and labeling.
• Rotate stock FIFO; periodically check open-circuit voltage for critical spares.

Compatibility and Alternatives

Series/Parallel Use

• Only combine identical cells of the same model, age, and state of charge.
• Use matched packs and consider cell balancing/fault containment for multi-cell designs.
• Avoid mixing chemistries or partially used cells with new cells.

Troubleshooting

Device resets during transmit

Increase local capacitance, verify RF power settings, and test at lowest temperature/near end-of-life.

Shorter-than-expected runtime

Re-measure real duty cycle; check for extra wake events, firmware changes, or colder-than-planned operation. Recalculate with margin.

Intermittent dropouts after replacement

Inspect holder tension and contact oxidation; replace worn holders and clean contacts.

FAQ

Is the LM26500-M rechargeable?

No. It is a primary (single-use) lithium cell and must not be charged.

Can it support short, higher-current pulses?

Yes, within its rated envelope. Use a local reservoir capacitor and validate under worst-case temperature and state-of-charge.

How does it compare to alkaline C cells?

It typically offers better energy density, a flatter voltage curve under load, improved cold performance, and longer shelf life.

Can I use multiple cells in series or parallel?

Yes, if you use identical, similarly aged cells and design for balancing and fault containment. Do not mix chemistries or new with used cells.

Is it suitable for sealed enclosures?

Use enclosures with appropriate venting and ensure thermal conditions stay within the cell’s operating range. Follow standard primary lithium handling practices.

Safety & Handling

• Do not crush, puncture, heat, or incinerate.
• Prevent short circuits with proper holders, covers, and fusing where user-accessible.
• Follow applicable transport regulations for primary lithium batteries.
• Recycle or dispose according to local regulations.

Deployment Checklist

• Confirm load profile (sleep/active/transmit) and peak currents.
• Select adequate bypass/reservoir capacitance for pulse loads.
• Set conservative voltage cutoffs aligned to device needs.
• Validate cold-start and end-of-life behavior.
• Specify robust, corrosion-resistant holders; document field replacement SOP.