battery's life
Battery manufacturers recommend that new batteries be slow-charged for 24 hours before use. A slow charge helps to bring the cells within a battery pack to an equal charge level because each cell self-discharges to different capacity levels. During long storage, the electrolyte tends to gravitate to the bottom of the cell. The initial trickle charge helps redistribute the electrolyte to remedy dry spots on the separator that may have developed. Some battery manufacturers do not fully form their batteries before shipment. These batteries reach their full potential only after the customer has primed them through several charge/discharge cycles, either with a through normal use. In many cases, 50 to 100 discharge/charg are needed to fully form a nickel-based battery. Quality cells, such as those made by Sanyo and Panasonic, are known to perform to full specification after as few as 5 to 7 discharge/charge cycles. Early readings may be inconsistent, but the capacity levels become very steady once fully primed. A slight capacity peak is observed between 100 and 300 cycles.
Most rechargeable cells are equipped with a safety vent to release excess pressure if incorrectly charged. The safety vent on a NiCd cell opens at 1034 to 1379 kPa (150 to 200 psi). In comparison, the pressure of a car tire is typically 240 kPa (35 psi). With a resealable vent, no damage occurs on venting but some electrolyte is lost and the seal may leak afterwards. When this happens, a white powder will accumulate over time at the vent opening.
Commercial fast-chargers are often not designed in the best interests of the battery. This is especially true of NiCd chargers that measure the battery¡¯s charge state solely through temperature sensing. Although simple and inexpensive in design, charge termination by temperature sensing is not accurate. The thermistors used commonly exhibit broad tolerances; their positioning with respect to the cells are not consistent. Ambient temperatures and exposure to the sun while charging also affect the accuracy of full-charge detection. To prevent the risk of premature cut-off and assure full charge under most conditions, charger manufacturers use 50¡ãC (122¡ãF) as the recommended temperature cut-off. Although a prolonged temperature above 45¡ãC (113¡ãF) is harmful to the battery, a brief temperature peak above that level is often unavoidable.
More advanced NiCd chargers sense the rate of temperature increase, defined as dT/dt, or the change in temperature over charge time, rather than responding to an absolute temperature (dT/dt is defined as delta Temperature / delta time). This type of charger is kinder to the batteries than a fixed temperature cut-off, but the cells still need to generate heat to trigger detection. To terminate the charge, a temperature increase of 1¡ãC (1.8¡ãF) per minute with an absolute temperature cut-off of 60¡ãC (140¡ãF) works well. Because of the relatively large mass of a cell and the sluggish propagation of heat, the delta temperature, as this method is called, will also enter a brief overcharge condition before the full-charge is detected. The dT/dt method only works with fast chargers.
The batteries and chargers supplied by one-battery.com are replacement for sold, All manufacturer brand names, logos and trademarks (such as Apple, Compaq, Dell, Gateway, HP, IBM, Motorola, Nokia, Panasonic, Samsung, Sony, etc) are the property of their respective holders and while we make reference to brand name merchandise we are in no way endorsed by or associated with these companies. Any use of a brand name or model designation for a non-OEM product is made solely for purposes of demonstrating compatibility.Any reference to products or trademarks of such companies is purely for the purpose of identifying the computer manufacturers with which our products.You agree that this limitation of liability is comprehensive and applies to all damages of any kind, including without limitation direct, indirect, compensatory, special, incidental, punitive and consequential damages.
