🔋 Battery amp-hour, watt-hour and C rating tutorial

About this video

• Video Title: 🔋 Battery amp-hour, watt-hour and C rating tutorial
• Channel: Afrotechmods
• Speakers: Afrotechmods
• Duration: 00:06:13

Overview

This video tutorial explains the fundamental concepts of battery capacity, focusing on amp-hours (Ah), watt-hours (Wh), and C ratings. It clarifies the difference between amps and amp-hours, how internal impedance affects battery performance, and how to compare the energy stored in batteries with different voltages using watt-hours. The tutorial also explains the practical meaning and calculation of C ratings for determining a battery's safe discharge current.

Key takeaways

• Amps vs. Amp-hours: Amps (A) measure the rate of current flow, while amp-hours (Ah) measure a battery's capacity, indicating how much energy it can store and deliver over time.
• Amp-hour Calculation: A battery's amp-hour rating estimates its runtime; for example, a 2Ah battery could theoretically supply 2 amps for one hour or 1 amp for two hours, though this is affected by discharge rate and internal impedance.
• Internal Impedance: Batteries have internal impedance that limits the maximum current they can deliver and causes energy loss as heat, affecting the battery's effective capacity and output voltage, especially at higher discharge rates.
• Watt-hours for Energy Comparison: Watt-hours (Wh) provide a more accurate comparison of stored energy between batteries with different voltages. It is calculated by multiplying the battery's voltage by its amp-hour capacity (V x Ah = Wh).
• C Rating Explained: The C rating is a simplified indicator of a battery's maximum safe discharge current. It's calculated by multiplying the battery's amp-hour capacity by its C rating (e.g., a 2.2Ah battery with a 20C rating can safely deliver 20 * 2.2 = 44 amps).