Ode to the AA Battery

AA vs. other chemistries and voltage behavior

• Several comments explain that 1.2 V NiMH vs 1.5 V alkaline is usually not why toys fail; well‑designed devices should work down to ~1.0 V and account for alkaline’s rapidly dropping voltage.
• NiMH cells hold a flat ~1.2 V for most of their discharge then fall off a cliff, which breaks simple “voltage = charge level” indicators; devices may falsely report “low battery” or “full until dead.”
• Some devices do misbehave on NiMH (older Apple mice, certain weather stations, testers, smoke/CO alarms calibrated to alkaline curves), which commenters call bad design.
• 1.5 V Li‑ion “AA” cells with internal converters and USB charging are praised as convenient but criticized for flat voltage curves that can confuse battery gauges.

NiMH / Eneloop ecosystem and chargers

• Many participants report running almost everything on NiMH (often Eneloop or similar LSD cells), citing reliability, no leaks, long life, and low self‑discharge.
• Others argue Eneloops are somewhat overhyped versus higher‑capacity NiMH cells, depending on use (storage vs immediate heavy use).
• There’s annoyance at cheap “pair‑only” trickle chargers and confusing status behavior; defenders note NiMH tolerates mild overcharge at low current, making such chargers cheaper but slow.
• Some prefer smarter per‑cell chargers despite higher cost and complain that most consumer chargers feel flimsy.

Alkaline leakage vs primary lithium

• Strong consensus that alkalines frequently leak and destroy gear, especially in rarely used devices (flashlights, remotes, toys, cameras). A minority say they’ve almost never seen leaks.
• Older “no‑leak” alkalines from specific brands are nostalgically remembered as better than current formulations.
• Several recommend non‑rechargeable lithium (Li‑FeS₂) cells for long‑term, low‑drain or critical devices: higher energy, long shelf life, wide temperature range, and no leaking, at a higher price.
• Debate appears around cases (like IR remotes or medical pumps) where alkaline discharge curves may still be preferred or specifically calibrated for.

Device design and replaceable batteries

• AA‑powered controllers (Xbox, Wii, some 8bitdo), keyboards, and mice are praised: instant swap, long runtime with quality NiMH, and no dependence on aging sealed packs.
• Sealed Li‑ion in phones, e‑readers, controllers, and gadgets is viewed as environmentally and practically worse: batteries fail first, replacements are hard to source and risky to install.
• Power‑tool ecosystems with long‑lived, backwards‑compatible packs (e.g., 18–20 V platforms) are admired; OEM vs off‑brand pack safety and lack of cross‑brand standards are discussed.
• Some call for regulation to standardize interfaces/battery packs; others warn against over‑prescriptive mandates but support interoperability requirements (similar to USB‑C rules).

Form factors and future standards

• Discussion of Li‑ion formats (18650, 14500/AA‑size, 10440/AAA‑size, RCR123A/16340) and the desirability of protected “nubbed” cells.
• Risk noted in visually identical AA and 14500: dropping 3.7 V cells into 1.5 V gear can over‑voltage devices; some mitigate via taped‑on dummies or dedicated lights that accept either.
• Several propose new standardized flat packs (phone‑battery‑like) with built‑in BMS, data pins, and stackability, to give future‑proof, user‑replaceable packs across devices.

Li‑ion deep discharge and safety

• A few admit to “jump‑starting” over‑discharged Li‑ion pouches by manually pushing a little current until normal chargers take over, reporting apparent success.
• Others caution this is risky: deep discharge can form lithium dendrites and internal shorts, raising fire/explosion risk.
• Anecdotes mention specialized “intelligent” chargers used to safely recover deeply discharged packs; details of what they actually do remain unclear.
• One commenter imagines a purpose‑built, safer recovery tool with temperature sensing and controlled trickle for such cells.

Usage patterns, training, and small hacks

• People describe going all‑rechargeable at home, labeling NiMH cells “do not dispose,” and training children to put all batteries in recycling so rechargeables don’t get thrown away.
• Outdoor enthusiasts are split: some insist on AA/AAA + solar so every device shares spares; others argue modern Li‑ion rechargeables plus a power bank are simpler and lighter.
• Multiple tips are shared for rescuing alkaline‑damaged contacts (vinegar to neutralize crust, then mechanical cleaning), but many ultimately conclude it’s easier to avoid alkalines entirely.