Instructables
Picture of How to Wire Batteries in Series (or in Parallel)
Get the power you need from the power you have by wiring together different power sources to get the voltage or the current to drive your project.

This is a simple insructable which will graphically demonstrate how to wire multiple power sources together to get the voltage and current you need for your project.

You will see that this demo uses a couple of my Al/Air fuel cells but you should be able to use any power sources you like.

It is not required that all the power sources be the same and this can affect your output. For instance wiring 3V and 9V batteries in series will give you 12V

Step 1: Bill of Materials

Picture of Bill of Materials
Okay you're going to need some batteries to wire together and some way to wire them together.

In this example we will be wiring together two aluminum air batteries so we'll need a couple of batteries and some leads for interconnecting them.

A multimeter for measuring voltage and current also comes in handy.

Other power sources that can be used include battery packs, wall warts ( two 9V warts = 1 18V ) or just about anything else.

Step 2: Wiring two batteries in series

Wiring multiple power sources in series will increase the available voltage.

First we measure the voltage from each battery. Then we wire them in series by connecting the negative lead (connected to aluminum foil) to the positive lead of the other battery.

Here we can see that two batteries, one with 850 mV and one with 774 mV produce 1.568 when wired in series. As you can see we lose a tiny bit of power in this circuit ( approximately .05 mV ) most likely due to the nature of the connections.

Now let's take a look and see what happens when we wire them in parallel...
 
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Mike__5 years ago
Putting voltage sources in parallel is potentially very dangerous, especially if there exists a difference in potential between the cells. The internal resistance will cause an over current (short) situation through one of the loads (cells) and may cause one cell to explode or catch fire. One should never put voltage sources in parallel, only current sources.
espdp2 Mike__2 years ago
I don't understand the terminology "voltage source" and "current source." Clarify please.
dhymers Mike__4 years ago
 I think this is true for ideal (ie, not real) voltage sources, but wiring up real batteries in parallel is standard practice as long as they are the same state of charge, chemistry, ah and voltage, otherwise its either slightly dangerous or useless.

I have a riddle which I can't figure out in relation to batteries (and current sources) wiring different batteries with differing AH's in series is not a good idea, and the ckt will be limited by the one with least capacity, but how can you show this on paper ?
Same is true of current sources (real ones, not ideal) I know series current sources isn't the norm, and ones with different values especially, how do you prove that one will be limited by the other ?
my head hurts.
ncblu dhymers4 years ago
batteries have an internal resistance which dictates what the current will be
ncblu Mike__4 years ago
you can parallel batteries - as long as they are the same voltage
angeleus3 years ago
I believe the bottom right battery is wired wrong.
mt52523 years ago
I have (2) 12v 5ah battiers wired in series and get short run can i change the battiers to say 12v (10 or 20) ah and get more run time on a 24v 5ah motor thanks i need help