This Battery Storage Loss Calculator estimates how much energy a battery loses when stored unused for a given number of months.
Each battery chemistry has its own natural self-discharge rate. Simply enter capacity, chemistry and storage duration and you’ll get the remaining usable capacity.
How Battery Storage Loss Happens
Even when not in use, batteries slowly lose charge through a process called self-discharge. The percentage depends on the internal chemistry.
Lithium batteries generally have lower idle loss compared to Lead-acid and NiMH.
Formula (per month):
Remaining Wh = Previous Wh × (1 − Loss%)
Typical Monthly Storage Loss by Chemistry
- Li-ion ≈ 3% / month
- LiFePO₄ ≈ 2% / month
- Solid-state ≈ 1.5% / month
- LTO ≈ 1% / month
- Lead-Acid ≈ 5% / month
- NiMH ≈ 10% / month
Best Storage Tips
- Store Lithium batteries at 40–60% charge
- Avoid full or empty storage
- Keep temperature around 15–25°C
- Recharge every 2–3 months if possible
Frequently Asked Questions
Q: Why do batteries lose charge during storage?
All chemistries experience internal chemical reactions that slowly reduce state of charge over time.
Q: Which battery has the lowest storage loss?
Solid-state and LTO typically have the lowest. LiFePO₄ is also excellent for long-term idle storage.
Q: Do I lose capacity permanently?
Most storage loss is temporary charge loss, not permanent capacity reduction, unless stored in extreme temperature conditions.
Q: Should I store at 100%?
No. Lithium batteries prefer partial storage (40–60%) for minimal degradation.
Q: Is LiFePO₄ best for long idle periods?
Yes. It has one of the lowest monthly self-discharge rates and excellent long-term stability.
