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How Many Watts Is a Motorcycle Battery? (Solved & Explained)

Motorcycle batteries come with some specifications that may be at first quite confusing to a new rider. However, the good news is that these specifications are easy to understand.

Often on motorcycle batteries, you will find the amps and the volts mentioned, but there may be no information about the watts. This brings us to a rather important question that many owners will ask themselves at one point or another.

How many watts is a motorcycle battery?  Generally, motorcycle batteries have between 15.75 Watts/h and 403.2 Watts/h depending on the battery’s Voltage and Ampere-hours. 12 Volt motorcycle batteries typically have more Watts than 6 Volt batteries, which is usually between 31.5 Watts/h and 403.2 Watts/h. 6 Volt batteries are between 15.75 Watts/h and 201.6 Watts/h.

As you can see, motorcycle batteries can be very different as not all of them are created equal. This is why below, I will go into more detail about all the small details and caveats worth knowing. Let’s take a look.

Usually we don’t qualify a battery by the number of watts it can deliver per hour. For a motorcycle battery, what will be important is the CCA the Ah and the Volts. We rarely talk about watts when talking about battery.

How Many Watts Is a Motorcycle Battery? (Solved & Explained)

Motorcycle battery specifications

Sine the watts of your motorcycle battery can vary a lot, it is recommended to understand how the electrical specifications actually work and how they affect each other.

Of particular interest to us will be the ampere (A) or ampere-hours (Ah) of the battery and its voltage (V).

You should find these specifications on all motorcycle batteries on the label or the user’s manual on all motorcycle batteries.

Volts (V)

If your motorcycle was made in the last 40 to 50 years, it most likely uses a 12 Volt battery.

Generally, motorcycle batteries are either 6 Volts or 12 Volts. Older motorcycles were designed to use a 6 Volt battery. However, in the early 1960s, both motorcycle and car manufacturers slowly switched to 12 Volt systems.

This means that there will not be a lot of variation when it comes to how many volts a motorcycle can be. However, a 6 Volt motorcycle should not be used with a 12 Volt battery and vice versa.

However, a 12 Volt battery is not exactly 12 Volts, and a 6 Volt battery is also not exactly 6 Volts. Motorcycle batteries are made of several battery cells, 12 Volt batteries have 6 cells, and 6 Volt batteries have 3 cells, and each cell is rated at 2.1 Volts. This means that 12 Volt batteries will actually be 12.6 Volts, and 6 Volt batteries will measure 6.3 Volts.

See article: Is a Harley Davidson Battery 6 Volt or 12 Volt?

Ampere-hours (Ah)

The amps of a motorcycle battery are also a very important specification that needs our attention. However, before we continue, let me stop you right here. Although many people are referring to the amps of a motorcycle battery, it is worth knowing that batteries are measured in ampere-hours (Ah).

Motorcycle batteries can be between 2.5 and upwards of 32 ampere-hours. The lower the ampere-hours, the smaller the battery is. The ampere-hours do not affect how much power the battery can produce, but rather for how long it can produce that power. In other words, a battery with lower ampere-hours has less capacity and will die sooner.

Cold cranking amps (CCA)

The other specification of motorcycle batteries that you will find often mentioned is the cold cranking amps (CCA). CCA measures the ability of the battery to start the engine in cold temperatures. The cold cranking amps are the amps a 12 Volt battery can deliver at 0°F for 30 seconds while not going below 7.2 Volts.

The CCA of your motorcycle battery is a very important rating of the batteries, but it is not going to be of particular use to us when it comes to finding out the Watts of a motorcycle battery.

How Many Watts Is a Motorcycle Battery? (Solved & Explained)

How to find out how many watts is a motorcycle battery

Some motorcycle batteries will have their rated watts already printed out on their label or spec sheet. However, most of them may not feature any such information, in which case you will need to find it out using a very easy formula.

Before we continue, let me mention that much like how motorcycle batteries are measured in Ampere-hours, we are also talking not about Watts but Watts-hours.

To find out how many Watts a battery is, all you have to do is multiply the Ampere-hours by the Volts. The formula is: (Wh) = (Ah) x (V).

For example, a 16 Ampere-hours motorcycle battery will have 201.6 Watts (or Watt-hours). Or 16Ah x 12.6V = 201.6 Wh.

Average Motorcycle battery Watts

Since we already know that motorcycle batteries can have between 2.5 and at least 32 Ampere-hours, we can calculate how much watts in general motorcycle batteries have.

For 12 Volt batteries, we have:

  • 2.5Ah x 12.6V = 31.5Wh
  • 32Ah x 12.6V = 403.2Wh

And for 6 Volt batteries, we have:

  • 2.5Ah x 6.3V = 15.75Wh
  • 32Ah x 6.3V = 201.6Wh

This means that generally, 12 Volt motorcycle batteries can have between 31.5 to 403.2 Watts. However, 6 Vol motorcycle batteries can have between 15.75 and 201.6 Watts.

Are the watts of your motorcycle battery important?

The wattage of your motorcycle battery is a number that can be used to determine how much current the electrical system is drawing from the battery.

Since we know that the Volts are fixed, this means that if we go over the battery’s rated wattage, we are trying to draw too much current out of it. In this case, there are two possible outcomes.

  • As the current exceeds the capabilities of the battery, the Voltage will drop, which may cause the motorcycle to not start or work properly. For example, the headlights can get dimmer, or the battery can discharge at faster rates, which can also seriously damage the battery.
  • The higher current that is continuously drawn can produce heat, which can melt parts of the electrical system and wiring. The fuses can also blow in order to prevent melting and fires.

Miscalculating the watts of your motorcycle battery and trying to draw too much current than what it is designed to supply is not recommended as it is not only a fire hazard but can also seriously damage the battery and other electrical components and accessories.

If you have difficulty to start your motorcycle check this articles Jump Start Your Adventure: How to Jump Start a Motorcycle.

However, since this is an electrical system that has fixed voltage, you may not necessarily need to convert everything into watts. If all accessories and devices you use are the same voltage the motorcycle battery supplies, all you need to do is ensure that you do not exceed the battery’s rated Amper-hours.

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