Using a multimeter to check lithium battery health is a valuable technique that can reveal a lot about a battery's condition without invasive measures. Whether it's an initial voltage check, investigating cell groups, assessing under load, or monitoring self-discharge, each method provides crucial data.
To measure the current (in amps) of a lithium-ion battery, you need to set the multimeter to measure current (A). Connect the negative (-) lead of the multimeter to the negative (-) terminal of the battery and the positive (+) lead to the positive (+) terminal of the battery.
The capacity of a cell is probably the most critical factor, as it determines how much energy is available in the cell. The capacity of lithium battery cells is measured in amp-hours (Ah) or sometimes milliamp-hours (mAh) where 1 Ah = 1,000 mAh. Lithium battery cells can have anywhere from a few mAh to 100 Ah.
Occasionally lithium battery cells are marketed with just a C rating and not a maximum current rating. This can make it easier to compare the power level of battery cells of different capacities. As long as you know the capacity of the cell, you can use the C rate to quickly calculate the maximum current rating of the cell.
Load Tester A load tester applies a controlled load to the battery and measures its voltage response. It also provides readings for current, resistance, and other parameters relevant to the test. Multimeter A multimeter measures voltage, current, and resistance during the load test.
Lithium ion battery capacity is the utmost quantity of energy the battery can store and discharge as an electric current under specific conditions. The lithium ion battery capacity is usually expressed or measured in ampere-hours (Ah) or milliampere-hours (mAh).