18650-0V-dat.md
0V issues
A Li-ion cell showing 0 V usually means something seriously wrong.
Two main causes:
1. Protection Circuit Tripped (Only for “protected 18650”)
Some 18650 cells include a tiny PCB at the bottom.
If the cell is over-discharged, the protection board disconnects the output → terminal voltage reads nearly 0 V.
- Internal cell voltage is usually still 1–2 V, not truly 0 V.
- Only applies if your cell is a protected 18650.
2. Cell Is Internally Damaged (Most common)
A fully unprotected or old 18650 can reach 0 V if:
- Severe over-discharge
- Internal chemical breakdown
- Internal short circuit
- Copper plating inside
- Safety vent (pressure valve) triggered
If the safety vent opens, the cell is permanently unsafe.
True 0 V = the cell is dead.
⚠️ Can You “Fix” a 0 V 18650?
No. Not safely.
Trying to recharge a 0 V Li-ion can cause:
- Fire
- Venting hot gas
- Explosion
- Thermal runaway
Even trained engineers only attempt recovery in fireproof labs.
For home use:
0 V = NOT repairable.
✔️ What You Should Do
- Do NOT charge it.
- Do NOT heat, hammer, or puncture it.
- Recycle it at an e-waste / battery recycling point.
This is the only safe option.