2. Power conversion The power-consuming components in a mobile computer—memory, the display and its backlight, the processor, the imaging system, and the wireless communication system—operate at a number of different DC voltages. DC voltage regulation reduces or boosts voltage from the battery to supply the proper voltage to all components. Mobile computer manufacturers have a wide variety of voltage regulators available. All lose some power in conversion, but high-efficiency regulators lose relatively little, thereby lengthening per-charge run time. Most industrial mobile computers are built with less-costly, comparatively inefficient voltage regulators.It’s more efficient to convert voltage down to meet a component’s requirements than it is to convert it up to a higher voltage. And it’s far easier to avoid up-conversion with stacked-cell battery packs providing 7.4 volts than it is with battery packs producing 3.7 volts. These components are: 1. The battery Mobile computer manufacturers can choose from a wide variety of batteries. Key variables include battery capacity and intelligence that can be built into the battery pack. Unfortunately, battery specifications can be confusing. For example, a battery pack with a rating of 3000 mAh (milli-Ampere hours) at 3.7 volts has less capacity than a pack with a rating of 2000 mAh at 7.4 volts. Watt hours (Wh), a more meaningful measure of capacity than mAh, takes voltage into account. It’s determined by multiplying a battery pack’s mAh rating by its voltage. In the example above, the 3000 mAh battery pack has a power capacity of 11.1 Wh, while the 2000 mAh pack has a power capacity of 14.8 Wh. More sophisticated portable designs that come with higher battery capacities usually have multiple cells and higher voltage ratings—for example, 7.4 volts instead of 3.7 volts. Increasing capacity increases run time, but that is not the only benefit: higher capacity batteries may need less frequent replacement. Lithium-ion batteries are durable and efficient power sources, however, like virtually all battery types, their ability to store power declines with each charge. The greater the discharge and subsequent recharge, the greater the loss of power storage capability. Most battery types used in portable computing have a typical lifespan of 500 complete charge/discharge cycles. But if the battery is routinely recharged before it is fully discharged, it can be recharged more times. Instead of being replaced after 500 discharge/recharge cycles, it may last for as many as 1,500 discharge/recharge cycles—three times as long. With a mobile computer that can operate for longer than a full shift on a single battery charge, the battery can be recharged well before it is fully discharged. Temperature is also a factor in battery recharging. If batteries are rapidly recharged at too high or too low a temperature, damage results and battery life is shortened—a common occurrence when batteries are charged in parked trucks. When the intelligence to sense temperature and commu- nicate with a charger is built into a battery pack, an intelligent charger can respond with smart charging that prevents battery damage. Unfortunately, most mobile computers are not equipped with intelligent batteries.

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Typical Mobile Computer Per-Charge Run Times Hours Up to6 HoursUp to8 HoursUp to10+ Hours 46810 2 StandardBatteries High-CapacityBatteriesBest inClass How Mobile Computer Power Management Impacts Operators’ Hard and Soft Costs