Longer Life Rechargeable Batteries

Sanyo announced an improved version of their Sanyo Eneloop Low Self-Discharge Rechargeable Battery, 6 October 2009 . These are now avialable in Australia and I purchased two AA cells from Dick Smith Electronics in Canberra.

These are Nickel Metal Hydride (NiMH) rechargeable batteries, which can be charged in the same sort of charger as other NiMH batteries. The main advantage advantage is that the Eneloop batteries will keep a charge for years, while normal NiMH batteries only keep a charge for months. The new batteries are claimed to retain 85% of their charge after a year, whereas normal batteries would be 50% discharged. Also they can be recharged 1,500 times, 500 times more than conventional NiMH batteries.

This makes NiMH batteries practical for low current applications, such as running a clock, where they previously they would not be of use.

Amazon.com adversities the Eneloop in AAA Battery 4 Packs
and the AA batteries in 4 Packs and 8 Packs. There is also mains powered charger with 4 AA batteries and a USB Charger with 2 AA batteries.

There is also a very elaborate "Eneloop Power Pack Kit" 8 AA and 2 AAA Batteries, plus 4 C and 4 D Size adapters.

There is a detailed "Review: Testing Sanyo's Eneloop Low Self-Discharge Rechargeable Battery" avialable, along with a comparison of the new Eneloop against other brand of batteries "Review: Pre-Charged (Low Self-Discharge) Rechargeable Battery Comparison".

It will be interesting to see if the technology is also applicable to batteries for hybrid and electric cars. One of the worrying costs with electric cars is replacing the battery pack. If the battery can be made to last 50% longer, that will reduce the cost. Also a car which can keep the charge longer will be more practical.

Aldi Ready to Use Rechargeable Batteries

Aldi is advertising AA and AAA Ready to Use Rechargeable Batteries. These are in packs of two for AU$7.99. The AA size are 2000 mAh and the AAA 800 mAh. These appear to be low discharge cells, simialr to SANYO eneloop , Sony Cycle Energy and Duracell Pre Charged. The advantage of these batteries is that they hold a useful charge for about a year and are compatible with chargers and devices which use ordinary nickel metal hydride (NiMH) rechargeable batteries.

Pre-charged Nimh C Cell Batteries

The low self discharge AA batteries I installed in a String Trimmer seem to have lost their charge after just under a year. This may be because they were left plugged into a dumb charger (the batteries are supposed to be disconnected from the cgarged when the are charged and then hold their charge). Or perhaps a year is all that can be expected in a heavy duty application from these batteries. Sub C cells, which the trimmer originally had, should offer more power.

Tenergy are offering Pre-charged Nimh C Cells on Amazon.com. The catch is that they are only 3000mAh capacity. It is likely these are actually AA cells fitted into a larger empty metal cylinder to make them up to C cell size. Other C cells are usually 5,000 to 10,000 mHa.

See also:

1. Pre Charged NiMH batteries
2. String Trimmers
3. glue guns
4. Battery chargers
5. replacement battery packs