Battery Self-Discharge
Self-discharge rates for common battery chemistries.
Reference
Self-discharge per month (at 20 °C)
| Chemistry | Rate | Shelf life (~80% remaining) |
|---|---|---|
| Alkaline | < 0.3% | 5–10 years |
| Lithium primary (Li-SOCl₂) | < 1% / year | 10–20 years |
| Lithium primary (CR/BR coin) | < 1% / year | 10 years |
| NiCd | 10–15% | Weeks |
| NiMH (standard) | 15–25% | Weeks |
| NiMH (LSD — Eneloop) | ~1% | 5–10 years at 85% rated |
| Lead-acid (flooded) | 3–5% | ~6 months before significant loss |
| Lead-acid (AGM) | 1–3% | 1 year |
| Li-ion (NMC) | 2–5% | Several months |
| LiFePO₄ | < 3% | Years at 30–50% SoC |
Storage tips
- Li-ion: store at 40–60% SoC, cool (but not frozen), dry. Full charge storage accelerates aging.
- Lead-acid: recharge every 3 months. Sulfation from deep discharge is permanent damage.
- NiMH: older cells self-discharge fast. Prefer LSD ("pre-charged") cells for occasional use.
- Alkaline: fine for emergency kits — store at room temperature, away from metal contacts.
- Freezer storage doesn't meaningfully help Li-ion and can damage the seals from condensation on removal.
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