Kinds of batteries and battery tips
2008-08-19

Kinds of batteries and battery tips

Lithium-ion battery

Lithium-ion batteries (sometimes abbreviated Li-ion batteries) are a type of rechargeable battery in which a lithium ion moves between the anode and cathode. The lithium ion moves from the anode to the cathode during discharge and from the cathode to the anode when charging. Lithium-ion batteries should be charged early and often. A new Lithium-ion battery will benefit from an initial "conditioning" of the battery. For the first 3 charge cycles, fully charge the battery overnight and allow it to fully discharge before recharging. And if they are not used for a long time, they should be brought to a charge level of around 40%–60%. Lithium-ion batteries should not be frequently fully discharged and recharged ("deep-cycled") like Ni-Cd batteries, but this is necessary after about every 30th recharge to recalibrate any external electronic "fuel gauge" (e. g. State Of Charge meter). This prevents the fuel gauge from showing an incorrect battery charge. To achieve a true full charge when rapid charging, the battery needs to be slow charged the last 10-15% of its charge cycle. Most "intelligent" desktop and Lithium-battery rapid chargers provide this capability. A Lithium-ion battery may be damaged by extensive overcharging (continuously on a charger for more than 24 hours).

NIMH batteryA nickel-metal hydride battery, abbreviated NiMH, is a type of rechargeable battery similar to a nickel-cadmium (NiCd) battery but using a hydrogen-absorbing alloy for the negative electrode instead of cadmium. As in NiCd batteries, the positive electrode is nickel oxyhydroxide (NiOOH). A NiMH battery can have two to three times the capacity of an equivalent size NiCd. However, compared to the lithium-ion battery, the volumetric energy density is lower and self-discharge is higher. NiMH historically had a somewhat higher self-discharge rate (equivalent to internal leakage) than NiCd in the past. However, this is no longer the case. The self-discharge is 5-10% on the first day, and stabilizes around 0.5-1% per day at room temperature. This is not a problem in the short term, but makes them unsuitable for many light-duty uses, such as clocks, remote controls or safety devices, where the battery would normally be expected to last many months or years. And the rate is strongly affected by the temperature at which the batteries are stored with cooler storage temperatures leading to slower discharge rate and longer battery life. The highest capacity cells on the market (> 2700mAh) are reported to have the highest self-discharge rates. It is very important to properly "condition" a new NiMH battery. For the first 3 charge cycles, fully charge the battery overnight (preferably on a conventional slow charger) and allow it to fully discharge before recharging. Over its lifetime, a NiMH battery will perform best if it is regularly charged on a charger/conditioner type charger. A NiMH battery may be damaged by extensive overcharging (continuously on a charger for more than 24 hours).

Nicd batteryThe nickel-cadmium battery, commonly abbreviated NiCd, is a type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes. NiCd batteries can charge at several different rates, depending on how the cell was manufactured. The charge rate is measured based on the percentage of the amp-hour capacity the battery is fed as a steady current over the duration of the charge. Regardless of the charge speed, more energy must be supplied to the battery than its actual capacity, to account for energy loss during charging, with faster charges being more efficient. For example, the typical "overnight" charge, called a C/10 charge, is accomplished by applying 10% of the batteries total capacity for a period of 14 hours; that is, a 100 mAh battery takes 140 mAh of energy to charge at this rate. At the "fast charge" rate, done at 100% of the rated capacity, the battery holds roughly 80% of the charge, so a 100 mAh battery takes 120 mAh of energy to charge (that is, approximately 1 hour and fifteen minutes) The downside to faster charging is the higher risk of overcharging, which can damage the battery. The Do’s and Don’ts of Battery Use Battery Do's: Fully charge/discharge battery up to 4 cycles before achieving full capacity of a new battery Fully discharge and then fully charge the battery every two to three weeks for battery conditions. Run the device under the battery's power until it shuts down or until you get a low battery warning. Then recharge the battery as instructed in the user's manual. Remove from the device and stored in a cool, dry, clean place if the battery will not be in use for a month or longer, Recharge the battery after a storage period Ensure maximum performance of the battery by optimizing the device's power management features. Refer to the manual for further instructions.

Battery Don'ts: Do not short-circuit. A short-circuit may cause severe damage to the battery. Do not drop, hit or otherwise abuse the battery as this may result in the exposure of the cell contents, which are corrosive. Do not expose the battery to moisture or rain. Keep battery away from fire or other sources of extreme heat. Do not incinerate. Exposure of battery to extreme heat may result in an explosion.