Energizer Ultimate Lithium (AA/AAA)

Energizer Ultimate Lithium are primary lithium iron disulfide (Li‑FeS2) AA/AAA batteries engineered for long runtime, strong cold‑weather performance, and low risk of leakage. They are not rechargeable.

When to choose these batteries

• High‑drain gear that needs steady voltage: LED flashlights/headlamps, digital cameras, GPS handhelds, professional audio/measurement tools.
• Cold or hot environments: reliable operation from −40°F to 140°F (−40°C to 60°C).
• Intermittent or mission‑critical use: emergency kits, first‑aid/response bags, sensors and trail cameras where long shelf life matters.
• Weight‑sensitive kits: about 33% lighter than comparable alkaline cells.

When to consider alternatives

• Daily‑use devices you recharge often (kids’ toys, game controllers, photography flashes used every day): choose low‑self‑discharge NiMH rechargeables to cut cost per use.
• Low‑drain remotes, clocks, basic radios: quality alkaline usually offers the best value.
• Devices that prohibit lithium primary cells or attempt in‑device charging of AA/AAA: follow the device manual—do not use lithium primaries where disallowed.

Performance snapshot

• Chemistry/format: Li‑FeS2 primary, 1.5 V nominal (AA/AAA).
• Operating temperature: −40°F to 140°F (−40°C to 60°C).
• Shelf life: up to 20 years (store cool and dry).
• Weight: AA ~15 g; AAA ~7.6 g (approx.), typically ~33% lighter than alkaline.
• Runtime: often 1.5–3× longer than alkaline in high‑drain or cold conditions. Actual runtime depends on device current draw and cutoff voltage.

Quick runtime estimator

Approximate runtime (hours) ≈ effective capacity (Ah) ÷ device current (A). At moderate loads, AA lithium cells often deliver around 3.0 Ah; AAA around 1.2 Ah. Capacity decreases at very high currents and varies by device cutoff settings.

Ultimate Lithium vs. Alkaline vs. NiMH Rechargeable

Criteria	Ultimate Lithium	Alkaline	NiMH Rechargeable
Upfront cost	High	Low	Medium (plus charger)
High‑drain runtime	Excellent	Fair to poor	Good to excellent
Cold‑weather performance	Excellent	Poor	Good
Shelf life	Up to 20 years	5–10 years typical	1–5 years; periodic charging needed
Self‑discharge	Very low	Low	Low on LSD types; higher on standard
Reusable	No	No	Yes (hundreds of cycles)
Best for	Critical or intermittent high‑drain use; extreme temps; emergency	Everyday low‑drain and budget uses	Frequent, cost‑sensitive use

Cost and value tips

• Deploy in gear where failure or frequent swaps are costly (expeditions, shoots, patrols). Use alkaline or NiMH elsewhere to manage budget.
• Carry spares: lithium cells hold voltage steadily, then drop quickly near end‑of‑life—having a spare prevents surprise shutdowns.

Safety and compatibility

• Do not recharge, short‑circuit, crush, or incinerate. Use the correct orientation.
• Do not mix chemistries or old/new cells in the same device.
• Check device documentation for lithium compatibility; avoid in devices with in‑device charging.
• For travel, protect terminals and follow airline rules for spare batteries.

Storage and handling

• Store in original packaging or a battery case in a cool, dry place.
• Remove from devices that will sit unused for months to reduce parasitic drain.
• Recycle according to local regulations.

FAQ

• Are these batteries rechargeable? No. They are single‑use primary lithium cells.
• Can I use them in any AA/AAA device? Generally yes, but follow the device manual. Do not use where lithium primaries are prohibited or where the device charges cells in place.
• Do they leak? They are designed with strong leak resistance and are less likely to leak than alkalines. Still remove batteries from seldom‑used devices.
• How do they perform in the cold? Much better than alkaline; they remain usable down to −40°F (−40°C).
• Why did my device shut off suddenly? Lithium cells hold voltage steadily, then drop quickly at end‑of‑life. Carry spares to avoid downtime.

Bottom line: Choose Energizer Ultimate Lithium when reliability, runtime, and temperature resilience matter more than lowest upfront cost.