Panasonic Eneloop Pro AA (BK-3HCD)

Eneloop Pro AA is a high-capacity, low self-discharge NiMH cell designed for devices that pull substantial current—camera flashes, LED flashlights, wireless mics, game controllers, and smart tools. Compared with standard Eneloop, it trades some cycle life for longer runtime per charge.

When to choose it

• Use if you need maximum runtime per charge in high‑drain gear (flashes, photo triggers, bright flashlights, game controllers).
• Use if you operate in cold conditions; NiMH holds up better than alkaline as temperatures drop.
• Consider standard Eneloop (≈2000 mAh, up to ≈2100 cycles) for low‑drain devices like remotes, clocks, or sensors where longevity per cell set matters more than capacity.
• Consider primary lithium AA (non‑rechargeable) for expedition use where recharging isn’t possible or for extreme cold below −4°F.
• Not a substitute for 14500 Li‑ion cells; those are 3.6/3.7 V and can damage AA‑only devices.

Key specs

Chemistry	Nickel‑Metal Hydride (Low Self‑Discharge)
Size / IEC code	AA / HR6
Nominal voltage	1.2 V
Capacity	Typical 2550 mAh; minimum 2450 mAh
Cycle life	Up to ~500 cycles (with proper charging and usage)
Self‑discharge	Retains about 85% after 1 year at 68°F/20°C (unused)
Operating temp (discharge)	−4°F to 122°F (−20°C to 50°C)
Recommended charging temp	32°F to 104°F (0°C to 40°C)
Dimensions	14.5 × 50.5 mm (AA standard)
Weight	≈30 g per cell

Runtime planning

Approximate runtime depends on device current draw and conditions. Use this quick estimate:

Runtime (hours) ≈ Capacity (Ah) ÷ Device draw (A) × 0.85 (the 0.85 factor accounts for real‑world losses and high‑drain effects).

• LED flashlight at 1.0 A: ≈ 2.2 hours per cell.
• Game controller averaging 0.20 A: ≈ 9–11 hours per set (2 cells in series keep the same Ah; runtime is similar to a single cell).
• Wireless mic at 0.05 A: ≈ 40–45 hours per set.

Note: Using two or four cells in series raises voltage, not capacity. Keep matched cells together as a set.

Charging guidance

• Use a smart NiMH charger with individual slots and −ΔV and/or temperature monitoring. Examples: Panasonic BQ‑CC17, BQ‑CC55.
• Recommended charge current: 0.3–1.0C. For 2550 mAh, that’s ~750–2550 mA. Common safe consumer rates are 500–1000 mA per slot.
• Charge time estimate: hours ≈ (Capacity mAh ÷ Charge current mA) × 1.2. Example: 2550 ÷ 800 × 1.2 ≈ 3.8 hours.
• Allow cells to cool after heavy use before charging. Avoid dumb timers or rapid chargers without termination.

Care and safety

• Do not mix brands, capacities, or old and new cells in the same device. Keep 2‑ or 4‑cell sets together.
• Avoid deep discharge. Replace/recharge when a device signals low battery; do not run cells flat below ~0.9 V under load.
• Store cool and dry (59–77°F / 15–25°C). For long storage, leave 40–80% charged and top up every 6–12 months.
• Recycle NiMH cells at approved drop‑offs; do not dispose in household trash.

Compatibility notes

• Most devices designed for AA alkaline work fine with 1.2 V NiMH because NiMH maintains voltage under load better than alkaline. A few devices may misread battery level—this is normal.
• Not interchangeable with 1.5 V lithium primaries or 3.7 V 14500 Li‑ion cells.

Pros and cons

• Pros: Long runtime per charge, stable output under load, good cold‑weather performance, low self‑discharge, fewer disposables.
• Cons: Fewer total cycles than standard Eneloop; heavier than alkaline; some devices show an early “low battery” warning due to 1.2 V nominal.

FAQ

Will the 1.2 V rating cause problems in my device?

In most AA devices, no. NiMH holds voltage better under load than alkaline, so performance is typically equal or better. Some devices may show a low‑battery icon early; this does not always indicate imminent shutdown.

How many cycles can I expect?

Up to about 500 cycles with proper charging and moderate temperatures. Very high drain, heat, or overcharging will reduce cycle life.

Can I mix Eneloop Pro with standard Eneloop in the same device?

No. Mixing capacities or ages can cause uneven discharge and shorten life. Use matched cells as a set.

Do I need to fully discharge before charging?

No. NiMH has minimal memory effect. Partial charges are fine and preferable to deep discharges.

Are they pre‑charged?

Yes, they ship ready to use. Topping them up before first use can ensure maximum runtime in high‑drain gear.