The voltage mentioned on the battery represents the maximum voltage across battery terminals. Hence for 12 V batteries, the maximum voltage across the battery terminal is 12 V and for the 24 V batteries, the maximum voltage across the battery terminal is 24V.

Also ‘Ah’ (Ampere/hour) capacity marked on the battery is the current a battery can provide over a specified period of time to a specific End of discharge Voltage at a specific temperature. Whereas the End of discharge Voltage is the level to which the cell voltage is allowed to fall to before affecting the load.

As the battery starts discharging, the voltage across its terminals starts reducing too but the rate of voltage drop throughout the discharging period is not too much high.

The voltage battery provides before it fails is called End of discharge Voltage.

**Difference between 12V and 24V battery**

The main difference between a 12V battery and a 24V battery is the amount of power stored in it. A 24V battery of the same ‘Ah’ rating as a 12V stores twice the power. Because the energy stored in the battery is given by multiplying battery voltage with Battery Ampere hour.

To explain the same, let's compare 12V, 200Ah and 24V, 200Ah batteries.

**Difference between 12V, 200Ah and 24V, 200Ah battery**

The amount of power stored in a 24V, 200Ah battery will be 24V x 200 Ah = 4800 Watt-hour (4.8kWh). And the amount of power stored in a 12V, 200Ah battery will be 12V x 200Ah = 2400Watt-hour (2.4kWh).

This means that for a similar load 24V, 200Ah battery will give twice the backup time as compared to 12V, 200Ah. And for a similar backup time of 24V, a 200Ah battery can run twice the load as compared to 12V, and 200AH.

Refer to the below table to better understand the **difference between the power store in 12V 200AH and 24V, 200 Ah batteries.**

**Let’s take two interesting case**

If you connect two 12V, 200Ah batteries in series then the output voltage will be doubled while the Ampere-hour remains the same and you will get a 24V, 200Ah Battery bank made out of two numbers of 12V, 200Ah batteries.

Also, if you connect two 12V, 200Ah batteries in parallel then the output voltage will be remaining the same but the Ampere-hour will be doubled and you will get a 12V, 400Ah Battery bank made out of two numbers of 12V, 200Ah batteries.

In both above cases, the store power of batteries remains the same, i.e. 4800 Watt-Hour (12V x 200Ah x 2).

I highly recommend you to read our blog “what is a 200Ah battery”for a better understanding of the 200AH batteries.

Similarly, we can differentiate between a 12V 100Ah and a 24V 100Ah batter

**Difference between 12V, 100Ah and 24V, 100Ah battery**

The amount of power stored in a 24V, ** 100Ah battery** will be 24V x 100 Ah = 2400 Watt-hour (2.4kWh). And the amount of power stored in a 12V, 100Ah battery will be 12V x 100Ah = 1200Watt-hour (1.2kWh).

This means that for a similar load 24V, 100Ah battery will give twice the backup time as compared to 12V,100Ah. And for similar backup time 24V, 100Ah battery can run twice the load as compared to 12V, 100AH.

Also, we can differentiate between a 12V 150Ah and a 24V 150Ah battery

**Difference between 12V, 150Ah and 24V, 150Ah battery**

The amount of power stored in a 24V, ** 150Ah battery** will be 24V x 150 Ah = 3600 Watt-hour (3.6kWh). And the amount of power stored in a 12V, 150Ah battery will be 12V x 150Ah = 1800Watt-hour (1.8kWh).

This means that for a similar load 24V, 150Ah battery will give twice the backup time as compared to 12V,150Ah. And for similar backup time 24V, 150Ah battery can run twice the load as compared to 12V, 150AH.

So whatever is the capacity of the battery, the definition of the difference between 12V and 24V battery will remain the same.

You're totally wrong about your series and parallel analysis.parallel connection will give the same voltage but different Current... While series connection will give same current but different voltage.