April 7 2009 01:12 PM
From Knowledge Central Answer #8986:
Intermec predominantly uses Lithium Ion (Li-ion) battery packs in its newer products. This battery type has many advantages over its predecessors. Your User’s Manual will indicate the type of battery used in your equipment. The label on the battery pack will also specify the type of battery being used.
As with any type of battery pack, it’s recommended that you charge the pack prior to using it. This is suggested as Intermec purposely ships new packs with a partial charge (approximately 35% of full charge) to prolong the life of the battery. An overnight charge is recommended prior to first use of the pack.
Intermec provides several options for charging your Li-ion battery pack. All of them provide a safe means to charge the battery. Typically, Li-Ion battery packs will take about four hours to fully charge. An LED indicator on the equipment is generally used to indicate a full charge. Be sure to always use Intermec specified chargers in order to provide maximum safety and battery life.
All types of battery packs will normally self discharge when they are stored for an extended period of time. This decreases the charge in the battery as the pack sets idle. Li-Ion packs have lower self discharge characteristics than most other battery chemistries. They will self discharge at a rate of about 5-6% per month at room temperature.
When you need to store these packs for any length of time, it’s not always practical to do it with a partial charge (such as 35%). Storing a Li-Ion pack at full charge for up to several months is not a problem if the ambient temperature is at normal room temperature or cooler. Actually, cooler temperatures are optimal. (Recommended storage temperature range is from 40-72 degrees F or 5-23 degrees C.) The Intermec specification for the minimum storage temperature is typically about -30 degrees Celsius. (Consult your User’s Manual regarding operating temperature for your specific battery pack.) The upper end of the storage temperature range is typically about 60 Celsius, although this high temperature is not recommended except for very brief periods of time. Since Li-Ion batteries provide power through a chemical reaction, these packs will permanently lose some capacity if they are stored for months at a time even when the best practices are followed.
This same temperature issue applies to usage and charge of the pack. Avoid leaving the battery on a vehicle’s dashboard where temperatures can quickly exceed the maximum recommended storage temperature.
Do not store these batteries for months at a time if the packs are at the point where they have almost no power. If the battery voltage is allowed to reach a certain minimum level, the pack may not be recoverable. Keep in mind that the battery power is constantly being used whether or not the battery is installed in the handheld. This is true due to the inherent self discharge characteristics of the battery cells and the small current being used by the supporting electronic circuitry.
Li-Ion batteries will provide a longer service life if they are not fully discharged with each use. Rather, these batteries prefer more frequent charges as opposed to draining all of the available power from them and then performing a recharge. Not all applications will allow this type of usage, but those that do will experience a longer life of the pack.
There are several things that can be done with your handheld computer to maximize battery run time. (These are detailed in your User’s Guide.) Under the Settings section, you can do the following:
* In the Power screen, check the box to turn off the unit when it hasn’t been used for a certain number of minutes. Set the time for the smallest amount that you can work with in your application.
* On the Battery Tab, move the sliders so that they are set to Max Battery Runtime (or as close to it as possible). There’s a trade-off here where you sacrifice RAM retention time (for when the unit will no longer power up due to a low battery) for retaining your data as compared to the time you will be able to use your handheld operationally.
* Set the Backlight to turn off very quickly from the point in time where the device is not being used.
The actual amount of run time will be dependent on these settings, your usage and several other factors. If your handheld has several radios and a scanner or imager, these will consume more power than those without these features. Frequency of usage of these features also affects the run time.
Intermec equipment will shut itself down when it detects that its battery is low. (This suspend condition will only occur after the user is given a visual indication well ahead of the occurrence of the event.) This self shutdown feature preserves the data on the handheld computer and protects the battery from being discharged too low into an unsafe condition.
An on-board electronic protection circuit is typically used in Intermec Li-Ion battery packs. This circuit is used to detect several potential unsafe conditions from occurring. If a potential unsafe condition is detected, the battery cells will be disconnected from the electrical terminals on the battery pack. Generally, these situations can be recovered from by placing the pack on charge (either in the handheld computer/dock combination or an external battery charger).
Never place the battery pack in your pocket where loose change or other items could short it out. This would apply to any situation that could short out the terminals. Although the pack is designed to be protected against this condition, it’s best not to allow this scenario to occur. Likewise, you should never place the battery pack near a heat source or allow it to get wet. This could damage the on-board protection circuit and allow the pack to become unsafe.
As the battery pack is used over many charge and discharge cycles, the available capacity (run time) will gradually diminish. When approximately 500 full charge/discharge cycles have been reached, the battery may only have about 80% of its original capacity. However, this is based on an ideal situation where the battery has been handled in optimal conditions. There are many factors that will affect the capacity over time. Some of these factors are storage and operational temperatures and the discharge rate that has been presented to the battery. Your application may not be as demanding as some, allowing you to use the battery pack well beyond this 80% or 500 cycle level. For example, If you discharge only to 50%, then this becomes a 1000 cycle life, 25% gives you 2000 cycles. Uses beyond the 2000 cycle limit, while theoretically possible, will approach the design limits of the battery.