Picking The Right Battery Tester For Your Product

Batteries are important components for many electronic applications, providing portable power for everything from electric vehicles (EVs) to wearable medical devices. But they must be tested in production and measured for regular maintenance, and battery test systems provide the means of checking the health of batteries of all shapes and sizes. Battery testers are available as function-rich, rack-mount systems and smaller, portable units. By understanding the capabilities of various battery test systems, batteries can be evaluated for voltage, current, power, and energy storage capacity over an expected operating lifetime. Some battery testers are “green” and highly efficient, returning most of the battery power during charge and discharge cycles to the energy grid for reduced test operating costs.

Rechargeable batteries such as lithium-ion (Li-ion) devices have gained considerable attention with the growing adoption of EVs. But lead-acid batteries have long been the electric power sources for vehicles powered by internal combustion engines. And batteries of all sizes are being developed and added to many smaller electronic applications including computers and communications devices. Although older architectures such as lead-acid batteries could be characterized by essential electrical measurements of voltage, current, and power, newer, rechargeable batteries such as Li-ion batteries must be evaluated for many more operating parameters, such as recharge rates and times and expected operating lifetimes. Modern battery test systems go well beyond simple voltmeters in their measurement capabilities and functions, with multiple measurement channels that allow, for example, simultaneous testing of source and sink currents during a battery’s recharge cycle.

A rechargeable battery may run in sleep or standby modes, with changes in current consumption. Testing newer rechargeable batteries requires a battery test system not only with sufficient electrical ranges but with the functionality to perform measurements that analyze battery performance under changing conditions. Insufficient switching speed when testing changing battery operating modes, for example, can result in false production-line test results which impact the production yields.

No matter the chemistry or design, batteries undergo loss of charge over time, a characteristic known as self-discharge. An ideal battery would store its rated maximum energy indefinitely, but all exhibit some self-discharge. A battery test system with sufficient measurement capabilities and control functionality can evaluate a battery under test or BUT for its amount of self-discharge under different operating conditions, such as changes in load and temperature. Finding a suitable battery test system is a matter of meeting the measurement requirements for the batteries to be tested.

Portable Power

Small size does not require sacrificing test capabilities as evidenced by the Keithley 2308 Battery/Charger Simulator. The multifunction tester is optimized for measuring battery power in mobile and portable electronic devices such as laptop computers and mobile telephones and can measure sleep, standby, and full operating currents at voltages from 0 to +15 VDC. It provides two independent power-supply channels, for a battery and its charger, with 1-mV resolution for the battery channel and 10-mW resolution for the charger channel, with both channels rated for maximum current of 5 A. The battery channel’s variable output resistance can simulate the internal resistance of a battery under test, allowing users to mimic the operating conditions of a DUT. The battery supply channel can also sink current to simulate a discharged battery. The charger channel provides voltage for evaluating battery charge control circuitry in an associated device, such as a mobile phone, with the battery channel as the load. The model 2308 tester features a wide dynamic range, including low current for sleep-mode testing, and can measure current pulses as narrow as 50 µs when analyzing transient events. It has load current measurement ranges with maximum values of 5 mA, 50 mA, 500 mA, and 5 A.

Most batteries lose energy over time because of a self-discharge process, even when the battery terminals are not connected to a load. The self-discharge behavior of rechargeable batteries such as Li-ion vehicle batteries is a major concern for the long-range use (in time and distance) of these charge cells. It is not a difficult measurement but is time consuming. A battery must go through multiple discharge/charge cycles as part of testing. To save time, use the Keysight BT2152B Self-Discharge Analyzer to more quickly measure how the open-circuit voltage (OCV) of a battery changes over time. Because manufacturers of Li-ion batteries typically devote long time periods to analysis of OCVs, they often maintain excess inventory to account for batteries made unavailable due to self-discharge testing. But rather than days or weeks to test the self-discharge characteristics of a Li-ion battery, the BT2152B uses a unique measurement approach to measure self-discharge in as little as 1 hour.

Another means of determining a battery’s self-discharge behavior is with the Hioki BT4560 Battery Impedance Meter. Rather than putting a DUT through multiple charge and discharge cycles, it measures the internal impedance of a battery at low frequency (1 Hz or less) to determine the battery’s tendencies for loss of energy. In a modular package measuring just 12.99 × 11.54 × 3.15 in (330 × 293 × 80 mm), It works with input voltages to +5 VDC and simultaneously measures voltage and impedance at different temperatures. While performing measurements as fast as 0.1 to 1.0 s, it provides high accuracy for low-impedance batteries, with test current of 1.5 A in the 3 m? impedance range, 500 mA in the 10 m? range, and 50 mA in the 100 m? range.

When battery testing involves the need for wide voltage and current ranges, the EA Elektro-Automatik BT 20080 Triple Battery Tester offers voltage testing in ranges with maximum settings as low as +10 VDC and as high as +900 VDC and current as low as 0 to 40 A and as high as 0 to 600 A/channel. The rack-mountable unit has three output ports and performs battery simulation testing as well as battery charge and discharge testing. It can quickly switch regulation modes, including constant-current (CC), constant power (CP), constant resistance (CR), and constant voltage (CV) modes in response to control circuitry connected to a BUT. The high-speed digital battery tester, with 16-b analog-to-digital converters (ADCs) and digital-to-analog converter (DACs), features 96% or more efficiency in returning power to the energy grid during discharge testing.

The NH Research 9200-4912 Battery Module/Pack Test System handles all battery chemistries, including lead-acid, nickel-cadmium (Nicad), and Li-ion batteries across wide ranges of battery voltage, current, and power requirements. The rack-mounted test system performs battery emulation, battery charger test, and power supply burn-in across six channels with as much as 12 kW power for voltages from +4 to +120 VDC and currents as high as 200 A. For voltages less than +4 VDC, the maximum power across six channels is 8 kW. Its 12-kW loads are bidirectional, supporting fast charge and discharge cycles, and with 87% of the input test power recycled.

For those in need of battery testing at high power levels, the NHR 9300-100 High-Voltage Battery Test System, tests at voltages as high as +600 VDC, current to 333 A, and power levels to 100 kW. For additional power, it occupies twice the floor space of the model 9200-4912, in two floor-standing racks. These represent a small sample of the battery testers we have available. For more information on these, please visit our website or contact a Transcat | Axiom Rental Account Manager for guidance at (760) 806-6600.