Duracell 9V PP3 HR22 Rechargeable Battery 170mAh NiMH

The Duracell 9V PP3 HR22 is a rechargeable nickel-metal hydride (NiMH) battery with a 170mAh capacity, designed for devices that require regular battery replacement at low to moderate drain rates. The battery arrives pre-charged and can be recharged hundreds of times using any standard NiMH-compatible 9V charger, reducing long-term running costs compared to single-use alkaline equivalents.

Common applications include smoke alarms, carbon monoxide detectors, wireless microphones, guitar effects pedals, digital multimeters, and portable radios where the 9V PP3 form factor is standard. The 170mAh capacity suits devices with intermittent or low-draw usage patterns rather than continuous high-drain applications. For smoke detectors in particular, rechargeables can be swapped and recharged on a schedule rather than relying on the detector's low-battery warning, which often triggers at inconvenient times.

NiMH chemistry delivers a nominal voltage of approximately 8.4V when fully charged, slightly lower than the 9V of a fresh alkaline. Most 9V-rated devices tolerate this difference without issue, but check device specifications if voltage sensitivity is a concern. The battery retains charge when stored, though self-discharge over weeks or months is typical of NiMH cells and faster than alkaline, so a top-up charge before use after long storage is recommended.

How many times can it be recharged?

Duracell specifies that this NiMH 9V can be recharged hundreds of times under normal use. Actual cycle life depends on charge/discharge depth, charger quality, and storage conditions. Expect 300-500 cycles before noticeable capacity loss.

What charger does it need?

Any standard NiMH-compatible 9V battery charger will work. Avoid chargers designed only for NiCd (nickel-cadmium) cells, as the charge profile differs. Smart chargers with automatic shutoff prevent overcharging and extend battery life.

Is it suitable for smoke alarms?

Yes, though check your smoke alarm's manual. Some manufacturers recommend alkaline only due to the slightly lower voltage and self-discharge characteristics of NiMH. If your alarm accepts rechargeables, the ability to swap and recharge on a fixed schedule avoids the nuisance of low-battery warnings at 3am.

Does it arrive charged?

The battery is pre-charged from the factory but may have lost some charge during storage and shipping. For best performance, give it a full charge in a compatible NiMH charger before first use.