Low self-discharge NiMH battery

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Example of a low self-discharge NiMH battery

The low self-discharge NiMH battery (LSD NiMH) was introduced in November 2005^[1]^[2]^[3]. 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. Aside from the longer shelf life, they are otherwise similar to normal NiMH batteries of equivalent capacity and can be charged in typical NiMH chargers. Low self-discharge NiMH batteries are good for photography and other high energy requirement applications.^[4] 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.

1 Charge retention
2 Brand names
- 2.1 Sanyo Eneloop
3 Price
4 References
5 External links

[edit] Charge retention

It is generally claimed that the 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).^[5]^[6]

[edit] Brand names

This new type of batteries is marketed with over a dozen different brand names, but only actually made by three companies – (Sanyo, Gold Peak and Yuasa).^[7]^[8]

Sorted by manufacturer and the product name:

AccuPower AccuLoop
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^[9]
Panasonic R2
Radio Shack Precharged
Rayovac Hybrid
Sanyo Eneloop^[10]^[11]^[12]
SBS BiReady
SKB ready2use
Sony CycleEnergy^[13] (manufactured by Sanyo^[14])
Sunmol AnyEnow
SWISSBATTERIES accubattery
Titanium Enduro
Uniross Hybrio^[15]
VARTA Consumer Batteries Ready2Use
Vapextech Instant

[edit] Sanyo Eneloop

Sanyo's Eneloop batteries are one brand of low self-discharge NiMH battery.

A Sanyo official has stated^[16]:

"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."^[17]

[edit] Price

Low self-discharge NiMH batteries are typically moderately more expensive than ordinary NiMH batteries and are sold in sets of 2 or 4 AA or AAA, with or without a charger. They are fully compatible with ordinary NiMH chargers.