Lithium-ion batteries power almost all laptop or notebook computers. These types of machine are becoming increasingly powerful, which, as a result, means that manufacturers are demanding more powerful batteries or cells. Manufacturers and suppliers, therefore, need a variety of battery testing equipment with arguably the most critical piece of battery tester equipment being a battery discharge tester.
What is a Battery Discharge Tester?
During an industrial battery service, battery discharge testing will assess the charge/discharge cycle of a computer’s battery. It will determine how long a battery takes to charge and discharge as well as learn how much the battery’s capacity diminishes after every charge. Using incredibly accurate precision equipment, manufacturers can make vital improvements to cells that will make them more efficient and be more appropriate for today’s sophisticated computers.
The Impact of Stress on Discharge
How a battery is both charged and used will impact on the cell’s long-term capacity. The extent to which each variable causes damage to the battery needs determining for modifications to be made. For instance, the entire industry acknowledges that overcharging cells negatively impacts on their capacity, but manufacturers need to understand to what degree. Battery tester equipment will overcharge a battery and then measure how much capacity is lost each time this happens. The goal is to limit the effect that it has so manufacturers can then offer practical solutions and remedies.
Also, increases in temperature during both charge and discharge can cause damage to the battery, reducing its capacity, potentially significantly, in a short period. During discharge testing, results will be quantifiable, and necessary changes and modifications can be carried out. Even the smallest improvements can give manufacturers a competitive advantage. Precision battery discharge testing is therefore crucial as it can be the most modest of amounts.
Issues with Over-discharge
When a battery is over-discharged, the charge drops rapidly after 95% of the energy has been spent. This final 5% of discharge can cause further damage to the battery and reduce capacity in future. As a result, many devices have fail-safe features that prevent over-discharge. However, in most cases, it is during industrial battery service testing that this level is determined.
Healthy batteries will be able to recover a nominal voltage after removing its load. Cells that have been exposed to parasitic loads or that have experienced high self-discharge will not benefit from voltage recovery. Once again, this is something that will become evident during battery discharge testing.
How is a Discharge Cycle Defined?
A discharge cycle is when a battery is fully discharged and then charged again. In reality, cells seldom undergo a full discharge, therefore manufacturers often refer to a formula known as the depth-of-discharge (DoD). With this formula, usually, 80% of the energy is available with 20% remaining in reserve as manufacturers appreciate that not fully discharging a battery increases its service life and replicates real-life situations. Of course, the figures used for DoD formula can vary as those used for electric vehicles may differ from those that are appropriate for notebook computers.
Can Batteries in Laptop Computers be Overcharged?
Lithium-ion batteries cannot be overcharged in a laptop computer even if they are left plugged in overnight as the device will have internal circuits that prevent charging until discharging some voltage. Indeed, this is a practice that many users adopt. The first charge for any battery in a laptop should be for a minimum of 24 hours.
What Can Users do to Help?
Lithium batteries have unstable properties which can impact battery life. It is not advisable to let your laptop battery completely discharge and keeping it discharged for any significant length of time can severely impact battery life. When a battery remains discharged, the retained voltage diminishes, damaging the cell and reducing its capacity when recharged.
Also, storing computers in an environment above 30 Celsius can lessen the cell’s life expectancy. Furthermore, recent studies by Battery University suggest that batteries should only be to 80-95% as this is the optimum level. These are all factors that only the user can influence, and even the most sophisticated battery testing equipment will not help in these circumstances.