Exploring the Benefits of Higher Watt-Hour Batteries
I recently conducted a project for my school science fair, and with the help of my dad, the editor-in-chief of Pro Tool Reviews, I was able to explore the integration of powerful tools into my experiments. The main goal of my project was to determine whether higher watt-hour batteries could provide extended work performance and ultimately save consumers both time and money. I wanted to find out if investing in a battery with more watt-hours would be a cost-effective decision in the long run, despite the higher initial expense.
My Hypothesis: Unleashing the Full Potential of Higher Watt-Hour Batteries
My hypothesis proposed that a higher watt-hour battery would yield a longer overall runtime. I believed that the battery with the greatest watt-hours would outlast others and drive the largest number of screws. This information would prove incredibly valuable to consumers. However, I also recognized the importance of being able to calculate the number of screws a high-capacity Li-Ion battery could drive, which served as the “control” in my tests.
To ensure accurate battery testing, several factors needed to be considered. With the support of Milwaukee Tool, who kindly provided an M12 brushless drill kit (2404-22) and different M12 batteries of various capacities, I was equipped to execute my experiments. While the batteries they sent were extended run models, I opted for the compact M12 pack to simplify the testing process and save time.
Setting Up the Experiment: Precision and Consistency
To commence the experiment, I fully charged all the batteries. With the assistance of my dad, we cut a 4×8 sheet of 3/4 plywood into 4″ by 48″ strips. These strips were then fastened together to create the test board. In total, we required 12 test boards, three for each battery. My brother and I meticulously marked a half-inch grid on each board using a marker, tape measure, and an Empire Level laser-etched square.
Once the marking was complete, we mounted the plywood on a pair of sawhorses. My dad then inserted the #2 Phillips bit into a Milwaukee brushless 12V drill/driver, ensuring a consistent depth of fastening to maintain balanced results. I began the testing process with a fully charged 14Wh battery, recording the number of screws it could drive before depleting. The test was repeated two more times with the same battery to obtain an average result. As the watt-hour capacity increased, I found myself using a significant number of screws!
Calculating Future Runs Based on the 14 Wh Control
In order to anticipate the number of screws that other batteries would secure, I devised a formula to calculate the value of “X.” This value represented the average number of screws secured per watt-hour for a 14 Wh battery (the control). By dividing the controlled average number of screws (181) by the watt-hours (14), the following equations and solutions were obtained:
- If 14 Wh produces 181 screws, then X = 181/14 = 12.929 screws/Wh
- For other batteries:
- 16 Wh • X = 207 screws
- 22 Wh • X = 284 screws
- 36 Wh • X = 465 screws
With these calculations completed, I was ready to compare them to the actual test results using different batteries.
Running Tests: Balancing Precision With Real-World Performance
Accurate testing required each battery to be tested three times to ensure consistency. I drove screws into the 3-ply plywood until each battery was drained, then recharged the battery and repeated the process. Finally, I calculated the average number of screws driven during each set of three tests and compared the results to the calculated quantities.
Overall, the actual results closely aligned with the calculated values, as demonstrated in the table above. The only notable discrepancy was found in the 36 Wh calculations and estimates. It is important to note the average number of screws per battery compared to the estimated figures. The data substantiated my assumption that batteries with higher watt-hours are capable of driving more screws, allowing for longer runtimes. Despite having the same voltage as the 14 Wh battery, the 36 Wh battery was able to drive twice as many screws.
Evaluating the Results: Considering the Impact of Battery Technology
Curious about the variations between the calculated and actual results for the higher watt-hour batteries, I discussed this matter with my dad. He explained that batteries with higher watt-hours are also newer. He further elaborated that advancements in battery technology could impact the results due to various factors. Batteries are not simply standalone power sources; they incorporate electronics and controls to monitor heat buildup, thereby preventing overloading and damage to the tool and battery pack.
Battery Capacity and the Price per Watt-Hour: A Surprising Revelation
Following the aforementioned calculations, I decided to delve deeper by examining the price per watt-hour (Wh). The results were astonishing. Higher watt-hour batteries actually boasted a lower cost per watt-hour. This could be attributed to cost savings through higher volume production or an update to a larger battery model. I calculated the price per watt-hour by dividing the total cost of the battery by its watt-hours. The chart below illustrates my findings (please note that the price for the 14 Wh battery is based on its original list price and is no longer available):
According to my calculations, a 16 Wh battery costs $39, resulting in a cost per Wh of $2.44. When considering a $49 22 Wh battery, the cost decreases to $2.23 per Wh. Surprisingly, the 36 Wh battery costs only $59, translating to a mere $1.64 per Wh. It is worth mentioning that the 14 Wh battery used to be priced at $39, making it the most expensive battery per watt-hour. These calculations shed light on some intriguing insights. Consumers who invest in more expensive batteries with higher watt-hours over an extended period will benefit from reduced costs, greater work capacity, and ultimately save time.
In Conclusion: Prioritizing Watt-Hour Capacity for Optimal Performance
In conclusion, when shopping for batteries to power your tools, it is crucial to prioritize higher watt-hour batteries. Watt-hours surpass higher voltages in terms of runtime efficiency. Remember this valuable insight the next time you find yourself browsing for batteries for your cordless power tools.
I thoroughly enjoyed working on this project for my school science fair, and I am proud to say that I secured third place and advanced to the county level. This experience has taught me that science can be both educational and enjoyable!