What Is The Difference Between Batteries In Series And Parallel

What does batteries in series actually do.

People often get confused about this. They don't understand what actually happens when you put two 12v 9ah batteries in series. What does it do to the voltage and the Ah, or ampere, being the storage ability. So connecting any batteries in series increases the voltage output. 12v + 12v = 24v.

In series, the batteries are connected in a way that the current flows in one direction from the positive terminal of one battery to the negative terminal of another, so doubling the voltage. 

You can see from this that the voltage has doubled but the Ah has stayed the same overall.

What happens when you put batteries in parallel.

Well the opposite actually happens.  When in parallel, the voltage stays the same but the Ah doubles so the storage doubles. 

So now you can see what happens in parallel. Adding to this, if you put 3 batteries in parallel the voltage stays the same but the Ah (ampere) or storage is increased by adding the Ah of each battery together. 

Can I use different batteries to put in series or parallel.

NO NO NO.  the batteries must be the same make, the same age, and the same Ah rating.

My gate kit is solar and has two batteries in it, How does that work.

If you have a solar gate system it is probably a 24v system so you will have two like batteries in series to make 24v because the controller needs 24v to operate and the motors are 24v.