Why does my Samsung EB-P4520 (20,000mAh, 45W) power bank drain completely within approximately 10 days even when not in use? Is this normal or a sign of a fault?
A Samsung EB-P4520 (20,000mAh, 45W) power bank completely discharging in 10 days without use is not considered normal, but there are a few factors to consider before assuming it's faulty:
Possible Causes:
1. Self-Discharge Rate (Normal): All lithium-ion batteries have a small self-discharge rate, typically 3–5% per month. Even with fast-charging circuitry and protection chips, 100% to 0% in 10 days is excessive unless:
2. Standby Power Drain (Likely): If the power bank auto-detects and supplies minimal current to a connected cable/device (even if it's "off"), it may be slowly draining power. Some models keep circuitry active for fast device detection.
3. Button Activated Circuitry: If the power button wasn't pressed to turn off output after charging something (or checking charge level), the power bank may stay in an active monitoring state, draining faster.
4. Temperature Extremes: If stored in a hot or cold environment, battery drain and degradation increase significantly.
5. Firmware or Hardware Fault: A defective internal control chip or aging cell could cause unusual parasitic drain.
What You Can Try:
Fully charge it and store it without connecting any cables. Recheck after 5–7 days.
Ensure the USB-C or USB-A ports are not in active detection mode (remove any cables).
Try resetting it if there's a hidden reset (usually by holding the button for ~10s — check manual).
Recommendation:
If the battery level drops significantly (e.g., 50% or more) in a week with no cables or use, it's best to contact Samsung support. It may be a warranty issue.
If it’s still under 1-year warranty, request a diagnostic or exchange, especially if you notice bulging, heat, or performance degradation.
