In the world of consumer electronics, numbers often tell a story that consumers find confusing. You buy a 20,000mAh power bank, but after charging your 4,000mAh smartphone barely three times, the power bank is dead. Mathematically, it should have provided five full charges.
Is the manufacturer lying? Not necessarily. The discrepancy lies in two technical terms that every distributor and consumer should understand: Battery Capacity and Rated Capacity.
At Honghao Electronics, as a leading manufacturer specializing in high-end wireless chargers and PCBA processing, we believe transparency and technical excellence are the keys to long-term partnerships. In this guide, we will peel back the layers of power conversion, circuit design, and why the PCBA (Printed Circuit Board Assembly) is the “heart” that determines how much power your device actually receives.
1. The Definitions: Battery Capacity vs. Rated Capacity
What is Battery Capacity?
Battery capacity refers to the total energy stored within the internal lithium-ion cells. Most power banks use cells with a nominal voltage of 3.7V. When you see “10,000mAh” on a box, it represents the cumulative capacity of those 3.7V cells.
What is Rated Capacity?
Rated capacity is the actual output capacity that a power bank can deliver to a device at a specific output voltage (usually 5V for USB standards). This is the figure that truly matters to the end-user. Because the output voltage (5V) is higher than the battery voltage (3.7V), the “available” mAh must decrease as energy is conserved.
2. The Physics of Power Loss: Why the Numbers Drop
There are three primary reasons why energy “disappears” during the charging process.
A. The Voltage Boost Process (Voltage Conversion)
Mobile devices charge via USB at 5V (or higher for Fast Charging). However, lithium batteries operate at an average of 3.7V. To charge your phone, the power bank must “boost” the voltage from 3.7V to 5V.
Using the principle of energy conservation, we can see that as Voltage goes up, the Capacity (mAh) must go down: Theoretical Capacity at 5V = (3.7V x Battery Capacity) / 5V
For a 10,000mAh battery, the theoretical output at 5V is only 7,400mAh — and that is before we even account for heat loss!
B. PCBA Conversion Efficiency
The PCBA is where the “magic” happens. It manages the voltage boost, safety protocols, and current regulation. However, no circuit is 100% efficient. High-quality PCBAs, like those manufactured by Honghao Electronics, achieve 85% to 95% efficiency. Lower-grade, cheap PCBAs may drop to 65%, meaning more energy is wasted as heat.
C. Wireless Charging Impedance (The Wireless Factor)
For our specialized products like long-distance wireless chargers or multi-functional wireless charging sockets, there is an additional layer of loss: Inductive Coupling Loss. Energy is lost as it travels through the air and through the phone’s casing.
3. The Honghao Electronics Advantage: Why Our PCBA Makes a Difference
As a professional electronic technology company with deep expertise in PCBA production and processing, Honghao Electronics doesn’t just “assemble” products; we engineer them.
Precision PCBA Engineering
The core difference between a “cheap” power bank and a Honghao product is the quality of the components on the PCBA.
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Low ESR Capacitors: We use components that minimize internal resistance.
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Advanced IC Controllers: Our chips provide smarter power distribution, ensuring that the conversion from 3.7V to 5V (or 9V/12V for PD charging) is handled with minimal thermal dissipation.
Thermal Management in Wireless Charging
Our Long-distance (Under-desk) Wireless Chargers utilize proprietary coil designs that optimize the magnetic field. By reducing heat on the PCBA, we ensure that the “Rated Capacity” remains as high as possible, providing a faster and more reliable charge.
4. How to Calculate “Real-World” Charges
If you are a distributor or a brand owner, you can use this formula to help your customers set realistic expectations:
Actual Output = (Battery Capacity x 3.7 x Conversion Efficiency) / Output Voltage
Example with Honghao High-Efficiency PCBA (90% Efficiency): For a 10,000mAh Power Bank charging at 5V: (10,000 x 3.7 x 0.90) / 5 = 6,660mAh
Example with Low-Quality Competitor (70% Efficiency): (10,000 x 3.7 x 0.70) / 5 = 5,180mAh
The difference is staggering. Choosing a partner with superior PCBA processing capabilities like Honghao Electronics means your customers get nearly 30% more actual power from the same size battery.
5.The Future of Integrated Charging
Honghao Electronics is at the forefront of integrating these technologies into everyday furniture and office spaces. Our product line includes:
Under-Desk Wireless Chargers
Eliminating clutter while maintaining high-speed power delivery through surfaces up to 30mm thick.
High-Density Power Banks
Utilizing the latest lithium-polymer cells coupled with our signature high-efficiency boards.
Multi-functional Wireless Charging Sockets
Combining AC power with DC wireless charging, requiring complex PCBA layouts to prevent interference.
Quality Control and PCBA Processing
Our factory utilizes SMT (Surface Mount Technology) lines with AOI (Automated Optical Inspection) to ensure every solder joint on our PCBAs is perfect. This rigor is why our products maintain a longer lifecycle and higher rated capacities than the industry average.
6.Transparency Builds Brands
In a crowded market, the “numbers game” can be tempting. However, at Honghao Electronics, we believe that educating the consumer about the difference between Battery Capacity and Rated Capacity is the only way to build a premium brand.
By focusing on high-efficiency PCBA design and innovative wireless charging solutions, we ensure that every milliampere counts. When you choose Honghao, you aren’t just buying a battery; you are buying optimized power delivery.
Partner with Honghao Electronics Today
Are you looking for a reliable OEM/ODM partner for wireless charging solutions or PCBA processing? Let our engineering team help you bridge the gap between theoretical capacity and real-world performance.
Contact us today to receive a technical consultation or a quote for our latest PCBA designs.