What is the output current of two batteries in series?

In summary: But in series, the current will always be the same.In summary, when two batteries are connected in series, the same current circulates in them due to their equal properties. This means that the output current will also be the same, regardless of their individual health. However, in real batteries, there is an internal resistance that can affect the actual voltage and current provided. Therefore, the output current may vary slightly depending on the external resistance in the circuit.
  • #1
hikari1987
4
0
when they have the same properties , the same current circulates in them because they are in series .. but the question is how to define the output current when there are two batteries , one in good health and the other defective so one deliver a high current and the other a lower one ?
thank you for your help !
 
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  • #2
Hello Ikari, welcome to PF :smile: !

the same current circulates in them because they are in series
still holds !
 
  • #3
BvU said:
Hello Ikari, welcome to PF :smile: !

still holds !

thank you :D

well actually given the chemical and physical properties of the batteries , the same current circulates in them when they operate at the same conditions , but when for example a battery delivers let's say I=2A and the other I=0.5 , which current would be the output ?

thank you again !
 
  • #4
It would be 0.5 A according to
the same current circulates in them because they are in series
.

There is a question mark to be placed here: If you put two batteries in series, the combination delivers a higher voltage, so the 'bad' battery doesn't have to "push" that hard, which means it may be able to deliver a bit more current.

Batteries are sold as "voltage providers" (you buy a 1.5 V battery, not a 0.5 A battery).
Ideal voltage providers deliver the nominal voltage, no matter what current is flowing. They don't exist (fortunately -- or there would be a lot more fires).

Our first approximation to describe the behavior of real batteries is to assume there is an internal resistance inside the battery. So if our 1.5 volt battery has to deliver 1 A and the actual voltage provided is 1.25 V we say that the internal resistance takes away 0.25 V at 1 A. Ohm's law tells us the internal resistance must be 0.25 Ω.

Actual batteries don't have such a simple linear behaviour for V as a function of I.
 
  • #5
Absolutely. A battery provides a certain voltage, say in this case, 1.5 V. If you have two such batteries in series, together they provide 3 V. provided both of them are still alive. It is not they they "give" a certain current. The current depends on the circuit that you connect. If, with the two batteries in series, you connect a 10 ohm resistor, you draw a current of 0.3 A. If you connect a 1 ohm resistor, you draw 3 A. This is assuming that the batteries are ideal, with zero internal resistance. For real batteries, you just add the internal resistance to the outside resistance you connected, in series. If you draw more current by using two small a resistance in the circuit, you just kill the battery sooner.
 
  • #6
hikari1987 said:
well actually given the chemical and physical properties of the batteries, the same current circulates in them when they operate at the same conditions, but when for example a battery delivers let's say I=2A and the other I=0.5 , which current would be the output ?

The question is invalid.

Two batteries in series will ALWAYS deliver the same current. It's not possible for them to deliver different currents if they are in series.

Two batteries in parallel could deliver different currents.
 

1. What does it mean for batteries to be connected in series?

Connecting batteries in series means connecting the positive terminal of one battery to the negative terminal of another battery, creating a single circuit with increased voltage.

2. How does connecting batteries in series affect the output current?

Connecting batteries in series does not affect the output current. The current remains the same as it would for a single battery, but the voltage is increased.

3. Can connecting batteries in series be dangerous?

Yes, connecting batteries in series can be dangerous if not done properly. It can lead to overheating, explosion, or other hazards. It is important to follow proper safety precautions and use appropriate batteries.

4. What is the formula for calculating the output voltage of two batteries in series?

The formula for calculating the output voltage of two batteries in series is Vtotal = V1 + V2, where Vtotal is the total output voltage and V1 and V2 are the individual voltages of each battery.

5. Is there a limit to the number of batteries that can be connected in series?

Technically, there is no limit to the number of batteries that can be connected in series. However, as more batteries are added, the voltage increases and can become too high for certain devices to handle. It is important to check the voltage requirements of your device before connecting multiple batteries in series.

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