Here are some examples of the types of battery performance parameters that are important for different types of applications. When starting a car, the battery is rarely drained of its full capacity. So, the amp-hour rating is less important, but the ability to deliver large surge currents for short durations, especially across a wide temperature range, is extremely important. Given that the battery is not being carried by hand, but mounted in a vehicle, the size and weight are relatively less critical. This is why lead-acid batteries remain dominant for this application even though other battery types might have lighter weight and higher capacity. Cordless power tools have greatly increased in popularity in the past several years. In the 1990s and up until about 2005, they were almost all powered by NiCd or NiMH batteries.This is because high current capability was required, but lead-acid would be too heavy for a handheld tool. In recent years, the new types of Lithium-Ion “power cells” that can provide high output current have started to take over this application. Since the new Li-Ion cells are so light weight, yet high voltage, power tools can now be made more powerful without becoming too heavy. Finally, for the small handheld devices like portable computers, tablets, mobile phones, and digital cameras, the high capacity, small form factor cells that are available using Li-Ion technology are critical to allow the small, thin products that are now the norm.