# Measuring a 9volt battery with a D.Multimeter

I try to measure a 9volt battery and it displays "9.14V". But the battery is empty. What is happening? Does the multimeter measures it's own 9V battery?

Can someone explain to me what i observe? How does a completely empty battery acts in a circuit with a multimeter?

EDIT When I connect a LED (without resistors) the battery is able to light it a bit, and then the multimeter displays 8.8V and falling. But if I disconnect the LED the voltage measured starts rising again until it reaches 9.15V again...

The weird thing is that the battery is almost empty.

• An empty battery acts like it's empty. Stick it across your tongue. If it hurts, the meter is right. If it doesn't, the meter is wrong.
– EML
Commented Nov 8, 2017 at 11:25
• No, the battery is not empty. Connect a LED in series with a 1 kohm resistor across the battery terminals, the LED should light up. If not reverse the polarity. How can an empty battery make a LED light up? The battery might not be able to deliver enough current for a different application but it is not empty. Commented Nov 8, 2017 at 11:26
• Thanks, this battery that displays 9.15V gives a small feeling in the tongue but it is not able to rotate a small motor. Another one that measures 4.5V rotates the motor fine... Commented Nov 8, 2017 at 11:28
• When a battery gets depleted, its internal resistance increases meaning the voltage drops when a (demanding, current hungry) load is connected. The battery can still drive a light load though like a LED. Commented Nov 8, 2017 at 11:28
• So I can understand that the "chemical damage" is kind of unpredictable Only if you load the batteries too much for too much time. Look at this datasheet: d2ei442zrkqy2u.cloudfront.net/wp-content/uploads/2016/03/… Note how at 250 mA, battery life is less than 2 hours. For a 9 V battery I'd stay below 50 mA peak current and a long time average current less than a few mA. Are your batteries all same brand and model? All same age? Only then can you compare fairly. Commented Nov 8, 2017 at 12:44