BU-913: How to Maintain Fleet Batteries

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Battery maintenance keeps batteries within a given performance standard and schedules replacement when the capacity drops below a set target. This utilizes each pack for its fully intended life without fear of unexpected downtime; it also enacts a solid replacement procedure. Device manufacturers support battery maintenance because it eliminates under-performing batteries and reduces the number of devices being sent for repair. Well-performing batteries reflect positively on the equipment; a win-win situation for all parties. 

Rechargeable batteries do not die suddenly but gradually get weaker with time. A service every 3 months or so offers plenty of assurance that all batteries meet the required capacity and last through the shift with extra energy to spare.

One of the simplest systems of battery maintenance is attaching a label that displays the last service, the due date, the capacity and the internal resistance. Figure 1 illustrates such a label. The system is self-governing in that a prudent user only picks a battery that has been serviced and meets the capacity requirements. Expired packs are analyzed, and when meeting the capacity requirements, they are relabeled and returned to service. Batteries that have slipped below the target capacity threshold are replaced or assigned to a less demanding use.

Fleet battery management

Figure 1: Sample of removable battery label. The label shows battery information at a glance with service and service due dates

Courtesy of Cadex

Figures 2 to 4 illustrate the battery label system involving [1] identifying batteries that are due for service, [2] analyzing and recertifying them upon meeting the requirements and [3] returning the qualified batteries to service while replacing the faded packs with new units.

Sorting batteries for servicing

Figure 2: Sorting batteries for servicing. When taking a battery from the charger, the user checks the service date and if expired, the battery is placed in the “To be serviced” box.


Servicing expired batteries

Figure 3: Servicing expired batteries. The analyzers service the batteries and recondition them if low in capacity (only nickel-based batteries receive recondition). Passing batteries are relabeled with new the capacity readings and the next service date.


Reinstating batteries

Figure 4: Reinstating batteries. Failed batteries are retired and replaced with new packs. The new and serviced batteries go back into service.

Setting up a battery maintenance system requires a battery analyzer that can print battery stick-on labels. The analyzer should also offer a program that automatically applies a corrective service if certain parameter thresholds cannot be met. Cadex analyzers satisfy these requirements and offer target capacity selection to establish the minimum performance criteria.

Most fleet operations use a capacity threshold of 80 percent as the battery pass/fail criterion. Increasing the threshold to 85 percent tightens the performance tolerance but passes fewer batteries; lowering the settings extends service life but relaxes the performance standards. When choosing the target capacity setting, the organization must ensure that the lowest performing battery is still able to fulfill its assigned duty. This can be done by examining the spare capacity after a busy day. (See BU-504: How to Verify Sufficient Battery Capacity.)

Another maintenance method is labeling each battery with a permanent ID number. The printer that is part of PC-BatteryShop™ (Cadex) generates these labels in bar code format. To service a battery, the user scans the label, which configures the analyzer to the service parameters and retrieves historic performance data for review. Besides service dates and capacity readings, purchasing date, vendor information and pricing can also be entered. Figure 5 illustrates the battery scan, service and data examination.

Fleet Batteries
Figure 5: Fleet battery management. Labeling each battery with a unique number simplifies battery service. Swiping the barcode label reveals the history of the battery.

Courtesy of Cadex

Smart batteries have the ability to store delivered performance taken by coulomb counting during discharge and charge. This data can be utilized with reasonable accuracy to estimate battery capacity without applying a full discharge cycle. (See BU-604: How to Process Data from a “Smart” Battery.) Occasional full discharges will still be needed to calibrate the battery.

Maintenance for critical systems can be shared on the cloud. Such a system oversees the performance of fleet batteries and assists in the budgeting to replace packs that have fallen below the target capacity. This enables a fully transparent battery maintenance system, virtually eliminating failures caused by underperforming batteries.

Battery maintenance, once a “fly by the seat of your pants operation” will see a firming up, leading to greatly improved battery reliability. Our expectation is not so much for a super battery that does not yet exist but in properly maintaining what we have.

Last updated 2016-05-27

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Comments (1)

On May 5, 2012 at 8:06am
mordecai wrote:

thank you for this site i hope it will help me in my new business for battery services