Which is better for a smoke detector?

The Ultimate Lithium. Its 25-year storage life and leak resistance suit detectors that sit for years, and it is rated for extreme temperatures. The E91 works but needs changing more often.

Which lasts longer in a camera or game controller?

The Ultimate Lithium. It is built for high-drain devices and delivers more usable runtime than alkaline. The E91 is fine for low-drain items like remotes.

Is the Ultimate Lithium worth the extra cost?

Only if the device is high-drain, hard to reach or exposed to heat or cold. At $30.00 for 4 at Walmart as of November 3, 2026, it costs far more per battery than bulk alkaline.

Can I store both for years?

Yes, but lithium keeps power up to 25 years versus 12 years for the E91. Store both in a dry place within their rated temperature range.

Are either rechargeable?

No. Both are single-use disposable batteries. For rechargeables, look at NiMH AA cells and a charger instead.

How many batteries do I get?

The Ultimate Lithium pack has 4 AA cells. The E91 pack has 48 AA cells, which suits households that burn through batteries in low-drain devices.

Energizer Ultimate Lithium AA Batteries vs Energizer E91DP-24 AA Batteries (48 Count)

Buy the Ultimate Lithium 4-pack if the batteries go in a smoke detector, camera, game controller or anything used outdoors in cold or heat. Buy the E91 48-count if you want a cheap bulk supply for remotes, clocks, toys and other low-drain devices. The lithium pack is $30.00 at Walmart as of November 3, 2026; no current price was given for the 48-count, so compare it against the lithium pack on cost per battery before deciding.

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