A charge display that jumps, or falls from two bars straight to shutdown, usually isn’t a dead pack — it’s the body’s estimate drifting away from the cell’s real state. The camera infers the percentage from the voltage curve and accumulated charge, and that estimate slides once internal resistance rises, temperatures drop, or you only ever do shallow cycles. Start with a full charge and discharge calibration: charge to full, run the camera down to automatic shutdown, let it cool, then charge to full in one go. Repeat once or twice and the display usually returns to normal. If it still jumps after that, look at capacity loss.
How the percentage is estimated
Understanding this helps you tell a display problem from a battery problem:
- Voltage method. Cell voltage falls gradually during discharge, and the body reads the remaining charge from it. Voltage also moves with load, so bursts, video and flash recycling pull it down momentarily and the display drops a bar.
- Coulomb counting. This tracks energy in and out, and needs a complete cycle to realign its endpoints. If you only ever recharge halfway, the endpoints get vague.
- Temperature compensation. Cold lowers voltage, so the body may show low early and appear to recover once warm. That’s normal, not a fault.
So a sudden drop to zero is often a momentary voltage sag shown as a display value. The underlying issue is that a worn cell sags further under load than a fresh one does.
Symptom and cause
| Symptom | Likely cause | What to do |
|---|---|---|
| Drops from two bars to shutdown | Rising internal resistance, estimate drift | Run one calibration |
| Shows 30%, empties quickly | Habitual shallow cycling, capacity loss | Calibrate; replace if no change |
| Falls fast in cold, recovers when warm | Temperature effect on voltage | Normal; keep packs warm |
| “Remaining charge may not be displayed accurately” | Standard message for a non-genuine pack | Keep shooting, watch the margin |
| Old reading still shown after a swap | Body hasn’t refreshed, system lag | Restart, refit the pack |
Calibration, step by step
Step 1 — Charge to full
Use a charger matched to the spec and take the pack all the way to full, unplugging only after the light turns green. Don’t interrupt it, and don’t use the pack while it charges.
Step 2 — Shoot until the camera shuts down
Fit the pack and use the camera normally until it reports the battery is exhausted and powers off. Real shooting load matters more than simply leaving it on, because the body needs a genuine discharge curve. If the camera idles for long stretches, fire a few bursts near the end to finish what’s left.
Step 3 — Let it cool, then recharge
A just-emptied pack runs warm. Take it out and leave it at room temperature for ten minutes or so, then charge it in one uninterrupted session until the light turns green. At this point the body’s estimate has been realigned once.
Step 4 — Repeat once or twice
One round often isn’t enough for a pack that has drifted a long way. Run the sequence one or two more times and watch whether the display becomes linear — falling evenly from full to shutdown rather than in big steps.
Step 5 — Record a baseline
After calibrating, note how many frames full-to-shutdown delivers and keep that as the pack’s baseline. Comparing against it once a quarter shows wear clearly and takes the guesswork out of retirement. For cycle and aging rhythm, see charging cycles and storage basics.
If calibration doesn’t fix it
- Runtime is genuinely shorter. Meaningfully fewer frames than the baseline — a third or more down — points to real capacity loss. Roughly 80% remains after 300–500 cycles, so replacing around two years is normal.
- Charging is also unreliable. Never turns green, or goes green the moment it’s plugged in: work through charging troubleshooting steps as well.
- There’s an error too. “Cannot recognize this battery” means follow the recognition troubleshooting steps.
- Something looks wrong. Swelling, deformation, heat or smell: retire it immediately and follow swollen battery safety steps.
Calibration fixes a display that has fallen out of sync with the cell. If the cell itself has aged, calibration only makes the display more honest — it won’t make the pack new again.
Habits that reduce dropouts
- Swap at one bar rather than running to shutdown. You avoid missing the moment and you avoid deep discharge.
- Do one full charge and discharge every month or two to give the body a chance to realign. No need to do it every time.
- In cold conditions, keep spares against your body and rotate them; judge remaining charge after warming.
- Number your packs and rotate, so none sits long enough to self-discharge into over-discharge.
- Leave margin when relying on the display. On non-genuine packs the percentage can be approximate, so go by bars rather than numbers.
FAQ
Does calibration damage the pack?
Once in a while, no. Frequent deep discharge does accelerate wear, so calibrate only when the display is clearly off — a few times a year is plenty.
Why does it drop from 100% to 80% after a few frames?
Usually because those first frames involved bursts, flash or video. The momentary load pulls voltage down and the display follows; it settles once you’re back to normal shooting.
Is the display less accurate with third-party packs?
Some Sony bodies show “remaining charge may not be displayed accurately” with non-genuine packs — a notice, not a fault. A compatible pack built to spec usually reads consistently enough for daily work after one calibration.
Still jumping after calibration — worth replacing?
If runtime is clearly below your baseline, replacing is the economical move. If the frame count is still healthy and only the display jumps, keep using it and build the habit of swapping early.
Swapping out a questionable pack means one less thing to worry about on a shoot: 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, with the larger TNP-FZ100 (2400mAh, roughly 17.3Wh) at about $19.66 / $24.70 / $39.92. Studios and rental houses refreshing stock in volume should use wholesale inquiry — orders above 100 units are quoted by batch.