Battery Testers

A battery tester is an electronic device intended for testing the state of an electric battery, going from a simple device for testing the charge actually present in the cells and/or its voltage output, to a more comprehensive testing of the battery’s condition, namely its capacity for accumulating charge and any possible flaws affecting the battery’s performance and security.

 there are numerous battery chemistries whose qualities must be assessed to judge their practicality for specific applications. Two terms often come up in battery test equipment: battery testers and battery analyzers.

Battery test systems that work with huge battery banks, and significant amounts of power, often are regenerative. Instead of just dissipating battery energy in a static load, the system will send the battery output to some sort of synchronous inverter. The inverter converts the battery energy to ac power that is routed back to the utility grid as an energy saving measure.

Battery testers can run a variety of measurements. Among the most common are tests of actual battery capacity, battery cycle life testing, characterization of battery dc internal resistance, Hybrid Pulse Power Characterization (HPPC) tests (for batteries in hybrids and EVs), electric double-layer capacitor (EDLC) tests, lithium-ion capacitor (LIC) tests, and several others.

Battery testers generally run capacity tests at the final battery charge and discharge rate to gain a more accurate image of capacity than given by ordinary tests which take place at high charge and discharge rates. The same philosophy generally applies to battery cycle life tests.

DCIR test waveforms and equivalent circuit of the battery under test, courtesy, Chroma.

Because battery internal resistance can depend on loading current, battery testers may gauge dc internal resistance (DCIR) using more than one method. For example, they may use the voltage difference caused by the change of several different loading currents. HPPC tests were created by the US DoE to assess EV battery qualities such as depth of discharge, conductive resistance, and polarization resistance. Battery testers handling HPPC tests often do so without any manual intervention by the operator.

The IEC 62391 standard governs EDLC characterization and calls for charging the capacitor before testing the capacity and then discharging according to a prescribed curve. EDLC capacity gets calculated from the discharge energy and spacing time at prescribed points. Moreover, test conditions depend on whether the intended EDLC application is for energy storage, memory backup, transient power, or a power application. Similarly, dc internal resistance tests employ calculations made from the discharge curve, discharge time, and difference in discharge voltage.

There are similarities between tests of LICs and EDLCs. The applicable standard for LICs is IEC62813 which specifies the LIC be fully charged before testing. Calculations of LIC internal resistance also use points on the discharge curve in calculations of the resistance value.

Such tests are generally beyond what battery analyzers can do, but are well within the capability of sophisticated battery test systems.

Most battery testers have two clips (or test leads), you first attach these to the battery’s terminals (connectors), then you press a button (or switch), and a few seconds later, the tester displays or prints a result indicating the battery’s condition. The details of how you use a battery tester depends on what kind of battery you have, the electrical system it is connected to, and which tester you plan to use. Some battery testers require disconnecting the battery from the vehicle, while others have different limitations. Most battery testers only work on one, or a few different types of batteries.

Why Batteries Get Old

• Electrolysis
• Sulfation
• Stratification

Overcharging can cause problems with a lead-acid battery, including loss of capacity and even explosions. This is because overcharging causes electrolysis, also known as ‘gassing’, which is the separation of water into hydrogen and oxygen. The loss of water can cause problems with electrolyte levels,