To continue our last post (Part One) of April 27^th, 2022. There are another two factors affecting the understanding of battery maintenance.

Myth 3: A multimeter is enough to measure the internal resistance of the battery

There are three reasons why a multimeter cannot be used to measure the internal resistance of a battery:

1. Method - As we all know, multimeters measure resistance based on Ohm's law, which only applies to metal conductors. However, the battery is a chemical battery, and its internal chemical reaction cannot be calculated by Ohm's law, so the internal resistance value measured by a multimeter has no reference significance. At present, there are basically three methods for measuring the internal resistance of a battery: the AC injection method to measure the internal resistance, the AC discharge method to measure the conductance, and the DC internal resistance discharge method. It is recommended that the engineer choose a professional instrument to accurately and reliably test the internal resistance of the battery.

2. Accuracy - The internal resistance of the battery is generally at the milliohm level, but the resistance resolution of an ordinary multimeter is about 0.1Ω, which does not meet the test accuracy requirements.

3. Safety - The resistance gear of the multimeter does not allow the voltage to be present on the object under test, but there is always voltage at both ends of the battery. Using a multimeter to test the internal resistance of the battery can easily burn out the multimeter.

Myth 4: The battery voltage is low, no need to pay attention to the safety level of the test equipment

According to the IEC61010-2-030 standard of the International Electrotechnical Commission, the battery test environment belongs to the CATIII electrical environment. Since the UPS or DC screen is not completely isolated from the mains, the instantaneous high-voltage shock in the power grid (due to lightning strikes or switching of capacitor cabinets, etc.) may be transmitted to the battery terminal and cause personal injury to the testers. Therefore, please use a battery internal resistance tester with at least CATIII 600V rating. The concept of CAT rating is not alarmist, and its design requirements ensure that there is sufficient creepage distance between the exposed metal part of the meter and the human hand when the test lead is subjected to an instantaneous high-voltage shock.

Powered & Powerful!

Distributors and OEM business are warmly welcome.

Get connected with professional lead-acid battery manufacturer,

www.gembattery.com

sales@gembattery.com

WhatsApp: +8615959276199