Your battery can go down while charging when the phone is using power faster than the charger can supply it, or when there’s a fault in the charger, battery, or charging hardware.

What’s Really Happening

Think of charging like filling a bucket with a tap while someone is drilling holes in the bottom. If water leaving is faster than water entering, the level still drops. The same happens when:

  • The charger is weak or faulty.
  • The cable or port is damaged.
  • The battery is old or degraded.
  • The phone is under heavy load (games, video calls, GPS, etc.) while charging.

Common Causes (Quick Scoop)

1. Charger or Cable Issues

  • Low‑power or cheap chargers can’t provide enough current, so the phone drains even while plugged in.
  • Damaged or low‑quality cables cause unstable or reduced power delivery.
  • Mismatched charger (wrong voltage/amp rating) can lead to very slow charging or net drain.

2. Heavy Usage While Charging

  • Gaming, video streaming, hotspot, or navigation can consume more power than the charger supplies, so the percentage drops.
  • Bright screen, high refresh rate, and loud speakers add extra load.
  • Background apps (social media, sync, cloud backup) can silently drain battery during charging.

3. Overheating

  • If the phone gets too hot, the system deliberately reduces or stops charging to protect the battery, so you may see the percentage stagnate or fall.
  • Heat comes from: gaming, charging under a pillow/blanket, direct sun, or fast charging in a hot room.

4. Old or Damaged Battery

  • Aged or heavily cycled batteries lose capacity and can’t hold charge properly, so they drop quickly even when plugged in.
  • Swelling, sudden shutdowns at 20–40%, or very fast drops from 100% to 90% are classic signs.

5. Charging Port or Internal Hardware Faults

  • Loose, dirty, or damaged charging port means power doesn’t flow properly, making the phone charge very slowly or drain.
  • Internal components like the power IC or sub‑board can fail, causing unstable or insufficient charging that you notice as “charging but going down.”

6. Software, Updates, and “Fake” Drain

  • Big OS updates, app updates, or sync/backups running in the background can temporarily cause strong drain during charging.
  • Sometimes the battery meter is miscalibrated, so the percentage jumps or drops even though the actual charge hasn’t changed much.

How to Fix It (Step‑by‑Step)

Step 1: Test the Basics

  1. Use an original or reputable charger with the correct power rating for your phone.
  1. Try a different cable that you know works well.
  2. Plug into a different socket or power strip to rule out a bad outlet or unstable power.

Step 2: Reduce Power Use While Charging

  • Close all heavy apps (games, video streaming, navigation).
  • Turn off hotspot, Bluetooth, GPS, and Wi‑Fi if you don’t need them.
  • Lower screen brightness or turn the screen off.
  • Ideally, let the phone charge while idle or even powered off for a test.

Step 3: Deal With Heat

  • Remove any very thick or insulating case while charging.
  • Don’t charge on soft surfaces (bed, couch, under pillow); use a hard, cool surface.
  • If the phone is hot, unplug it, let it cool to room temperature, then try again.

Step 4: Check for Battery or Software Issues

  • Look at battery usage in settings to see if one app is consuming an unusual amount.
  • Update your operating system and apps to the latest versions.
  • If percentages seem wrong (for example, instantly dropping from 100% to 90%), do a simple calibration:
    1. Charge to 100%,
    2. Use it down to around 5–10%,
    3. Then charge uninterrupted back to 100%.

Step 5: Inspect Hardware

  • Gently clean the charging port with a non‑metallic tool (like a wooden or plastic toothpick) to remove lint and dust.
  • If the cable wiggles a lot or only charges at certain angles, the port may be loose or damaged and needs a technician.

When You Should Worry

You should consider professional repair or battery replacement if:

  • The battery continues to drop while charging even with:
    • Original charger and cable,
    • Minimal usage,
    • Normal temperature,
    • Different power outlets.
  • The phone gets abnormally hot, smells burnt, or shows visible swelling (screen lifting, back cover bulging).
  • It shuts down suddenly at higher percentages or never really charges past a certain point.

In those cases, the safest move is to stop using the device, avoid charging unattended, and get it checked by an authorized service center, as a severely damaged battery or power circuit can be a fire risk.

Mini TL;DR (Bottom Line)

If you’re asking “why is my battery going down while charging,” the most common culprits are a weak/faulty charger or cable, very heavy phone usage while plugged in, overheating, or an aging battery. Try a known‑good charger, cool the phone, minimize usage while charging, and check battery health; if it still drains, you’re likely looking at a hardware or battery issue that needs repair or replacement.

Information gathered from public forums or data available on the internet and portrayed here.