Battery Storage
Edit on GitHubStoring 18650 cells correctly: the storage voltage, temperature rules, and the calendar of checks that keeps cells alive.
Battery Storage
Most cells are killed by storage, not by use. The three storage mistakes: stored full, stored empty, stored hot. This page is the correct procedure.
The storage voltage
| State | Voltage | Effect |
|---|---|---|
| Stored full | 4.2 V | Fastest aging; calendar capacity loss |
| Stored empty | below 2.8 V | Cell damage, possible death |
| Storage charge | 3.6 - 3.8 V (40 - 60%) | Minimal aging |
The rule: store at 3.7 V, roughly 50%. A beacon coming out of storage at 50% is also ready to use faster.
Temperature
- Ideal storage: 10 - 20 C, dry.
- Never store in a hot car or on a radiator: heat accelerates every degradation process.
- Cold storage is fine (the chemistry tolerates it) but condensation is not: dry, sealed storage wins.
The calendar
| Interval | Check |
|---|---|
| Every 3 months | Measure the voltage; top up to 3.7 V if below 3.6 V |
| Every year | Run a capacity check (see Battery Troubleshooting) |
| Every 2 years | Replace cells that fail the capacity check |
The long-term storage decision
For a beacon stored for a season: leave the cell in place at 50% or remove it? Removing it protects the device’s springs and the cell’s contacts, but a beacon with no cell cannot be picked up and used. The compromise: cell installed, at 50%, checked quarterly.
Related pages
- Charging and Cell Care for the charge side
- Beacon Care Seasonal for the device rhythm
- 18650 Battery Guide for the cell