w00d's Photo Muse: LSD-NiMH Rechargeable Batteries

Monday, December 10, 2012

LSD-NiMH Rechargeable Batteries

Low Self Discharge (LSD) are an improved type of NiMH rechargeable battery introduced in 2005 and are the only type of battery I will use. Here's why, given the self discharge rate of conventional NiMH Batteries (let's call them old tech) being unacceptable I've found the following brands will meet my needs. Therefor needing batteries that are ready to go at a moments notice I found on average LSDs will have a longer shelf life as they will retain most of their stored capacity by year end giving approximately 1500 re-charge cycles or more. The 'eneloop' brand are claimed to hold their charge for 5 years with 1,800 cycles. LSD rechargables are also available in Triple-A (AAA) sizes.

According to a battery tutorial from photo tuts+ "Conventional NiMH batteries at the approximate capacity loss of 10% after the first 24hrs and 1% per day after will loose just over ½ of their capacity by month's end." This is why Conventional NiMH rechargeable batteries are unsuitable for powering clocks, TV remotes or any device where it's batteries are expected to last a long time. Conventional (old tech) NiMH rechargeable batteries simply self-drain too fast.

Quote: Low Self Discharge (Wikipedia) NiMH are "a new type of nickel–metal hydride cell (the low self-discharge nickel-metal hydride battery, LSD NiMH) was introduced in 2005 that reduces self-discharge and therefore lengthens shelf life. By using an improved electrode separator and improved positive electrode, manufacturers claim the cells retain 70% to 85% of their capacity after one year when stored at 20 °C (68 °F). These cells are marketed as "hybrid", "ready-to-use" or "pre-charged" rechargeables. Standard NiMH batteries may lose half their charge in the same time period. Retention of charge depends a lot on the battery's impedance or internal resistance (the lower the better), and on the size of the battery as well as the mAh rating. Besides the longer shelf life, they are otherwise similar to traditional NiMH batteries of equivalent capacity and can be charged in typical NiMH chargers"