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What is Watt Hour? Why is it Important?

What is Watt Hour? Why is it Important?

Heres a short introduction to Milwaukee batteries before you begin!


A higher Wh reading means that your battery will last a longer time for the same application. Watt hours help to determine the life of the battery. Capacity voltage and output plays some part in powering the motor - but a higher Wh guarantees better capacity.

This means regardless of your brand's voltage rating and Ah rating, Wh is the consistent determinant for battery life.

Where do I find the Wh, I only see Ah?

Battery performance is determined in Wh. This is a function of the electrical configuration of the Li-On cells inside the battery. The Wh of Milwaukee batteries are located at the bottom of the battery pack.

This has some relation to the Ah of the battery. 
M18 B5 (5.0Ah) has a 90Wh capacity
M18 HB12 (12.0Ah) has a 216Wh capacity

Depending on the motor of the tool you are powering and the amount of resistance your application has (eg, cutting a thin metal sheet vs cutting through a concrete slab); the Wh will have a direct relation to the performance of your tool.

If powering a more efficient motor, less power is required and therefore less strain is put on the battery. Having better Wh batteries are always advantageous.

This also explains why some tools last longer or shorter with the same batteries.

"Motors determine the power output"
"Batteries determine the motor operation time at a certain capacity"


More on motors....

In the spec sheet you may find "no load" specifications. When working with tools, the motor will definitely be under load. Stress on the motor means that more power will need to be drawn from the battery. Things that require more stress would be cutting through concrete, drilling through very thick wood, or suction on thick surfaces in the case of vacuums.

Great. Where do I go from here?

Get on the right system. Buy some Milwaukee tools.

Milwaukee batteries are generally superior to most competitor batteries in the market. Aside from Wh, its important to look at cycle time - which refers to the amount of charges and the consistency of power output after many charges. Li-On cells often lose some capacity to produce consistent output over time and investing in a quality battery means you get more work done before needing to recharge. 

Finally, it is also important to pick the right tool for the job. Having the right blade attachment for cutting through concrete, means that your tool can perform up to expectations and not put unnecessary stress on the motor.


If you have any questions please feel free to contact us for more product advise.



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