You bought a "20,000mAh" power bank expecting roughly 4 full phone charges, but you're only getting 2-3. This isn't a defect — it's how power bank capacity actually works, and almost no seller in Pakistan explains it clearly.
What "Rated mAh" Actually Means
The number printed on a power bank (e.g., 20,000mAh) refers to the capacity of the raw internal battery cells — measured at the battery's native voltage (usually 3.7V), before any conversion happens.
Why You Never Get the Full Number
Your phone charges at 5V, not 3.7V. Converting power bank voltage up to phone-charging voltage isn't lossless — energy is lost as heat during this conversion, plus additional loss in the internal circuitry and cable. The realistic result: a "20,000mAh" power bank typically delivers around 12,000-14,000mAh of actual usable charge to your phone — roughly 60-70% of the rated number.
A Simple Way to Estimate Real Capacity
Take the rated mAh and multiply by approximately 0.6-0.65 to estimate real-world usable charge. A 10,000mAh power bank realistically delivers 6,000-6,500mAh — enough for about 1.5-2 full charges on an average modern smartphone, not the 2-3 the rated number might suggest.
This Isn't Unique to Cheap Brands
This voltage-conversion loss happens with every power bank, including premium ones — it's basic physics, not a quality shortcut. What separates a good power bank from a poor one is how close it gets to that realistic 60-70% figure, and whether the manufacturer is honest about it rather than implying you'll get the full rated number.
What This Means When Buying
- Don't buy based on the biggest mAh number alone — buy based on your actual charging needs
- For 2 full smartphone charges, look for at least 15,000-20,000mAh rated capacity
- For a full day of heavy use or load shedding backup, 20,000mAh+ is a safer buffer than the math alone suggests
Genuine Power Banks at AvaNext
AvaNext stocks the genuine Xiaomi 20,000mAh Power Bank and Anker PowerCore Essential 20,000mAh — both genuine cells with fast charging, nationwide Cash on Delivery.
Frequently Asked Questions
Is a power bank defective if it doesn't deliver its full rated mAh?
No — this is normal, expected behavior due to voltage conversion loss, not a manufacturing fault.
How many phone charges will a 10,000mAh power bank realistically give me?
Roughly 1.5-2 full charges for an average modern smartphone, accounting for real-world conversion loss.
0 comments