The low self-discharge NiMH battery
) was introduced in November 2005
. It reduces self-discharge
and, therefore, lengthens shelf life compared to normal NiMH batteries
. By using a new separator, manufacturers claim the batteries retain 70 to 85% of their capacity after one year when stored at 20 °C (68 °F). These cells are marketed as "ready-to-use" or "pre-charged" rechargeables.
Low self-discharge NiMH batteries are good for photography and other high energy requirement applications. Due to the low self-discharge, they are also suitable for long-term intermittent or low-current uses; they might last up to a year between charges, much better than ordinary NiMH batteries. They can therefore also be used for electrical clocks, remote controls, etc.
Aside from their longer shelf life, and moderately higher prices, they are otherwise similar to normal NiMH batteries of equivalent capacity and can be charged with normal NiMH chargers.
It is generally claimed that low self-discharge NiMH batteries retain 90% of their charge after six months, 85% after a year and 70% after two years, when stored at 20 °C (68 °F).
Low self-discharge NiMH batteries are marketed with over twenty different brand names, but only actually manufactured by five companies: Sanyo
, Gold Peak
Sorted by brand name and product name:
- AccuPower AccuLoop
- AgfaPhoto direct energy
- Alcava All in One
- Ansmann maxE
- Conrad Electronic Endurance
- Duracell ActiveCharge
- Duracell Pre-charged
- Gold Peak ReCyko
- Hähnel Synergy
- Kodak Pre Charged
- Maha Powerex Imedion
- Nexcell EnergyON
- Panasonic INFINIUM
- Panasonic R2
- Powertech Enekeep
- Radio Shack Precharged
- Rayovac Hybrid
- Sanyo Eneloop
- SBS BiReady
- SKB ready2use
- Sony CycleEnergy (manufactured by Sanyo)
- Sunmol AnyEnow
- SWISSBATTERIES accubattery
- Titanium Enduro
- Uniross Hybrio
- VARTA Consumer Batteries Ready2Use
- Vapextech Instant
's Eneloop batteries are one brand of low self-discharge NiMH battery, rated at capacities of 800 mAh for AAA, 2000 mAh for AA, 3000 mAh for C, and 5700 mAh for D batteries (C and D sizes announced August 2008).
A Sanyo official has stated:
- "The Eneloop batteries are sold charged, but not necessarily 100% fully charged. In Europe we charge them about 75%."
- "Several long term tests have shown that the self-discharge rate decreases over time. This means that Eneloop batteries discharge relatively fast at the beginning and relatively slower the longer you store them."
- "Higher temperatures substantially increase self-discharging. It is best to store Eneloops as cool as possible to keep the charge in the battery. As a rule-of-thumb, every 10 °C increase in storage temperature is equivalent to doubling the discharge rate."
- "The chemical decomposition of the cathode has been reduced substantially by the use of a new super lattice alloy."