Saft LS-33600 (3.6 V, 17 Ah) — Long-Life D-Size Li‑SOCl₂ Battery

The Saft LS-33600 is a D-size primary lithium-thionyl chloride cell designed for multi-year, maintenance-free power in low-drain devices. Its bobbin construction delivers high energy density, very low self-discharge, and reliable performance from −60°C to +85°C.

When to Choose This Cell

• Use if: Your device averages ≤0.1–2 mA with short, occasional pulses (e.g., meters, remote sensors, asset trackers, memory backup) and needs 5–20+ years of standby life.
• Use if: You need wide temperature performance for outdoor, industrial, or cold-chain environments.
• Avoid if: Your load is high and continuous (≥10–50 mA), or you require frequent heavy pulses without a pulse buffer. Consider a spiral Li‑SOCl₂ cell (e.g., Saft LSH series) or add a capacitor/HLC.
• Avoid if: You need a rechargeable solution. This is a primary (non-rechargeable) lithium metal cell.

Practical Runtime Planning

Nominal capacity is 17 Ah at low drain. Actual service life depends on load profile, temperature, and pulse handling.

• Rule of thumb: Estimated years ≈ 17,000 mAh ÷ average mA, then reduce for self-discharge and conditions.
• Example A (ultra-low drain): 0.1 mA average → 17,000 ÷ 0.1 ≈ 170,000 h ≈ 19 years. Real-world: typically 10–18 years after derating.
• Example B (moderate low drain): 1 mA average → ≈ 1.9 years ideal; expect ~1.5–2 years depending on temperature and pulses.
• Example C (continuous 10 mA): ≈ 70 days ideal; not an optimal use case for bobbin Li‑SOCl₂.

For devices that transmit briefly (e.g., 100–300 mA for 0.5–2 s), add a low-ESR capacitor (tens to thousands of µF, sized by pulse width and voltage droop) or consider a hybrid cell with an HLC to protect the primary cell and maintain voltage.

Key Specifications

• Chemistry: Lithium‑Thionyl Chloride (Li‑SOCl₂), bobbin type
• Nominal voltage: 3.6 V
• Nominal capacity: 17 Ah (at low drain/ambient conditions)
• Size: D (approx. Ø33.4 mm × 61.6 mm)
• Weight: ~90–100 g
• Operating temperature: −60°C to +85°C
• Typical self-discharge: <1% per year at 20°C
• Recommended continuous load: low mA range; short pulses supported with buffering
• Construction: Stainless steel can, hermetic glass-to-metal seal
• Compliance: RoHS and REACH (check current datasheet for latest regulatory approvals)

Integration Notes

Pulse Handling

• Use a buffer capacitor (low-ESR electrolytic or polymer) sized to your peak current and allowed voltage dip. Start with 220–1,000 µF for light telemetry and scale up as needed.
• Keep leads short and use adequate trace width to reduce voltage droop during pulses.

Passivation and Voltage Delay

• After storage, Li‑SOCl₂ cells can show a short “voltage delay” under initial load. A brief pre-load or a staged start-up can mitigate this.
• Test your device’s cold-start behavior at expected minimum temperature and after storage.

Series/Parallel Use

• Only combine fresh cells of the same brand, model, and lot. Do not mix old and new cells.
• In series packs, include cell protection to prevent reversal. In parallel, use current-limiting and consider isolation to avoid cross-discharge.

Mechanical & Terminations

• Standard D holders typically fit; verify dimensions and spring force.
• For soldering, use tabbed/lead versions. Do not heat the cell can directly.

Safety and Handling

• Primary cell — do not recharge. Risk of leak or vent if charged, shorted, crushed, or heated.
• Store cool, dry, and ventilated (ideally 0–30°C). Keep in original packaging until use.
• Avoid short circuits; use protective covers and handle with insulated tools.
• Dispose/recycle per local regulations for lithium metal batteries. Do not incinerate.
• Ships as a lithium metal battery; transport is regulated. Follow applicable shipping rules.

Alternatives and Selection Tips

• Higher pulse demand: Consider spiral Li‑SOCl₂ D cells (e.g., Saft LSH series) or hybrid cells with an HLC.
• Similar form/chemistry: Other D-size Li‑SOCl₂ cells (often designated ER34615) can be compatible; verify dimensions, pulse capability, and discharge curves.
• Rechargeable need: Use Li‑ion with a suitable BMS instead of Li‑SOCl₂.

FAQ

Is the LS-33600 rechargeable?

No. It is a primary lithium metal cell. Do not charge.

How do I support 200–300 mA transmission bursts?

Add a low-ESR capacitor sized for the pulse. Validate voltage droop at end-of-life and minimum temperature. For heavier or frequent pulses, consider a spiral or hybrid Li‑SOCl₂ cell.

What service life can I expect?

Low-drain applications (≤0.1–0.2 mA average) commonly achieve many years. Actual life depends on average current, temperature, self-discharge, and pulse profile. Model with your real load.

Can I use cells in series or parallel?

Yes, with care. Use matched, fresh cells; include protection to prevent reversal and cross-discharge; and follow the manufacturer’s pack design guidance.

Any special storage advice?

Store cool and dry (0–30°C). Long storage can increase passivation; test the device’s start-up after storage and at low temperature.