Direct answer: no, don’t run it flat. Lithium cells have none of the memory effect that nickel-based packs did; what they dislike is deep discharge and sitting at full charge. Top up whenever it’s convenient and keep day-to-day use in the 20–80% band. Long-term storage is the case that needs a rule: hold 40–60% charge, keep it cool and dry around 15–25°C, and top up every three months. Treated that way, most packs retain about 80% of original capacity after 300–500 cycles, so replacing around the two-year mark is a normal rhythm rather than a failure.
What counts as one cycle
A common misconception is that plugging in once equals one cycle. It doesn’t. A cycle is the cumulative discharge of 100% of rated capacity.
- Shoot down to 60% and recharge (40% used), then do the same tomorrow — those two sessions together make one cycle.
- Draining from full to shutdown and refilling is also one cycle, but it’s harder on the cell.
- So charging more often doesn’t burn extra cycles. What consumes life is total energy discharged and depth of discharge.
Depth of discharge versus lifespan
| Habit | Typical depth | Cycle count | Note |
|---|---|---|---|
| Shallow cycles (30–80% band) | About 50% | Higher | Longest life; good daily default |
| Normal use (20–90%) | About 70% | Medium | Balances convenience and life |
| Run to shutdown, then full (0–100%) | 100% | Lower | Comparatively more wear |
| Stored at full charge | — | Clearly shorter | Worse again in heat |
These are experience-based ranges. Roughly 80% capacity remains after 300–500 cycles, so a pack that feels noticeably shorter after a year is showing normal aging, not a fault.
Heat is the other half of the aging story, and it’s easy to underestimate. Time spent at high charge in a warm environment wears a cell faster than the same time spent at a moderate charge in a cool one. A pack left on a dashboard for an afternoon, or charged straight after coming in from a hot car, is doing itself no favors — and no charging habit offsets that.
Good charging habits
- Top up whenever. Plug in when you get home rather than deliberately draining first.
- Don’t sit at zero. Left discharged for long, cell voltage can keep falling into over-discharge territory, and in bad cases the pack won’t accept charge again.
- Don’t sit at 100% either. Full-charge storage speeds up aging; if you’re not shooting for a few days, bring it down to 40–60% before putting it away.
- Unplug once the light turns green. Green means full. Leaving a pack parked on the charger gains nothing.
- Warm is fine, hot is not. Slight warmth while charging is normal. Clear heat to the touch, any smell, or a deformed shell means stop immediately and take it out of service.
- Charge at room temperature. Around 15–25°C is ideal. Let a pack recover after a hot car or a freezing day before charging.
- Use a charger that matches the spec. Correct voltage and interface, from a known source — unbranded chargers often skip protection circuitry.
Storing packs you won’t use for a while
- Hold 40–60% charge. That’s the balanced state for storage; better than full or empty.
- Keep them around 15–25°C, dry, out of sunlight, away from radiators and damp.
- Top up every three months. Packs self-discharge even unused, and skipping this can drop them into over-discharge.
- Protect the terminals — original packaging or a cap — so they can’t meet metal.
- Rotate through your packs instead of using one favorite while the rest sit untouched.
When to replace
Work through the signs in this order:
- Runtime clearly shorter. Meaningfully fewer frames than when it was new in the same conditions, with temperature and settings ruled out.
- Charge level jumping. Dropping from two bars straight to shutdown points to rising internal resistance. Try one full calibration first — see how to recalibrate the charge display — and replace if it doesn’t help.
- Charging problems. Won’t turn green, won’t accept charge, or empties quickly after a full charge; charging troubleshooting steps covers this.
- Physical damage. Any swelling, deformation, leak or smell means retire it now and follow swollen battery safety steps. No further charging or discharging.
- Abnormal heat. Hot to the touch in normal use or while charging is also a stop-using signal.
For anything physical or heat-related, replace first. It isn’t worth risking an incident to save the price of one pack.
It also helps to set a replacement budget rather than reacting pack by pack. If you shoot regularly, retiring a couple of packs a year and keeping the rest in rotation costs far less than a mid-shoot failure, and it keeps your baseline consistent so you can plan battery counts with confidence.
FAQ
Does a new pack need a 12-hour first charge?
No. Lithium cells have no conditioning procedure. Charge it until full and use it; overcharging does more harm than good.
Does unplugging at half charge hurt it?
No. Shallow charging is kind to lithium cells. Plugging and unplugging freely is better than deep discharging.
Is it bad to run the camera until it shuts down?
Occasionally, it’s fine — just don’t make it a habit. Repeated deep discharge accelerates capacity loss and tends to catch you out at the wrong moment.
Do third-party packs have shorter cycle life?
That depends on the cells and build quality; a pack built to the same spec can come close. A genuine Sony NP-FZ100 runs $70 and up through official channels, so the appeal of compatible packs is kitting out several to rotate at a far lower cost — which suits anyone running multiple bodies.
Several packs in rotation beat squeezing one to its limit: our NP-FZ100 compatible battery is rated 2280mAh / 7.2V / roughly 16.4Wh, around $17.89 per pack, around $22.93 with one charger and around $36.74 for two batteries plus charger; the higher-capacity TNP-FZ100 (2400mAh, roughly 17.3Wh) runs about $19.66 / $24.70 / $39.92. Studios and rental houses swapping out aging stock should use wholesale inquiry — orders above 100 units are quoted by batch.