Can I measure a battery internal resistance with a normal multimeter?

djxpress

Newly Enlightened
Joined
Feb 22, 2021
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My multimeter has an Ohms setting. Or do I need a specific meter to test this?
 

NiOOH

Enlightened
Joined
Oct 14, 2006
Messages
431
No. In order to measure IR of batteries, you'll need a special meter or a charger that can do this. If you measure with your multimeter, you'll get a very high resistance or an open circuit, which is the insulation resistance of the separator.
IR is measured either at 1 kHz AC or at DC. With the AC method, some small alternating current is applied to the battery and the corresponding voltage is measured. DC method measures the voltage drop under constant load. The two methods, usually give different results, the DC method giving higher IR values. Care should be taken to eliminate parasitic resistances in the circuit. Some expensive multimeters can measure IR of batteries, but the usual ohmic resistance meter is useless in this case.
 
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