A lithium battery built for power-hungry devices
Camera, GPS, motion detector, motorised toy: the Ultimate Lithium AA targets uses that draw a lot of current, exactly where a standard alkaline battery quickly shows its limits. Its single-use primary lithium chemistry clearly sets it apart from a rechargeable battery like the Eneloop.
A runtime gain that depends entirely on the device
This is the single most important point to understand before buying this battery: its real advantage over a standard alkaline varies enormously depending on the device used. In a motorised toy, the runtime gain exceeds 60%; in a power-hungry audio device, the gap stays roughly the same. In a low-drain device such as a clock or a clock radio, that gain drops to under 5%, a difference barely noticeable in use. The rule is simple: the more current a device draws, the more a lithium battery is worth it over an alkaline; for a low-drain device, the extra cost does not translate into a proportional runtime gain.
A 25-year shelf life claim that cannot be verified over such a timespan
Energizer states a shelf life of up to 25 years in storage, a figure obtained through accelerated-ageing methods rather than direct observation over a quarter of a century, which remains standard practice for this type of claim in the industry. No independent source can confirm this precise figure over the real timeframe, for obvious calendar reasons. What is solidly established is the gap in shelf life against a standard alkaline battery, which is markedly less enduring in long-term storage, making the Ultimate Lithium AA a good choice for backup batteries left sitting in a drawer for years.
A confirmed edge in the cold, without verification at -40 °C
Energizer states operation from -40 °C to 60 °C, a much wider range than a standard alkaline battery. This extreme figure remains a manufacturer claim, with no independent measurement to confirm it at this precise level; under more moderate cold conditions, however, the Ultimate Lithium AA held the best voltage among the lithium batteries compared, a real edge in the cold that does not, on its own, validate the extreme figure printed on the packaging.
A caveat on flash photography, despite being promoted
Flash photography is among the uses the manufacturer recommends, but reality calls for some nuance. In an external flash unit, the Ultimate Lithium AA recycles more slowly between flashes than a rechargeable NiMH battery such as an Eneloop, due to the higher internal resistance inherent to lithium chemistry. In return, it allows a higher total number of flashes before running flat. For occasional use, where the wait between two flashes barely matters, that is not an issue; for burst shooting or intensive professional use, a rechargeable NiMH battery stays more responsive.
A leak-resistant battery, with no safety concerns reported
The Ultimate Lithium AA is designed to resist leaks, a reassuring point for backup gear stored for a long time without supervision. Nothing points to any particular safety issue with this battery. Being single-use, it should be recycled at end of life like any primary lithium battery, through a dedicated collection point.
Against the two rechargeable Eneloop batteries
How do you choose between the disposable Ultimate Lithium AA and the rechargeable Eneloop batteries in our line-up?
| Criterion | Energizer Ultimate Lithium AA | Eneloop AA | Eneloop Pro AA |
|---|---|---|---|
| Type | Disposable lithium | Rechargeable NiMH | Rechargeable NiMH |
| Cold performance | -40 °C announced | Not stated | Not stated |
| Shelf life | 25 years (storage) | 70% / 10 years | 85% / 1 year |
| Reusable | No | Yes, ≈ 1,000 real-world cycles | Yes, ≈ 150-170 real-world cycles |
| Observed price (x4) | £9.38 | ≈ £17.54 (prorated x8) | £22.15 |
The Ultimate Lithium AA earns its keep for backup use, outdoors or in severe cold, where its long shelf life and cold-weather performance outweigh the recurring cost of a disposable battery. For everyday use in devices recharged regularly, Eneloop batteries remain cheaper over time and more eco-friendly.
