A pack that won’t charge is rarely dead. In most cases the problem sits in one of four places: power supply, contact, temperature or over-discharge. The seven checks below run easiest first and need no tools: confirm the outlet and charger are live, then look at seating and contacts, then consider temperature and long-term storage, and only at the end conclude the pack has aged out. Ten minutes or so. Don’t start by assuming the battery is finished.
Read the symptom first
| Symptom | Likely cause | Check |
|---|---|---|
| No indicator light at all | Dead outlet, loose cable, faulty charger | Steps 1, 2 |
| Light blinks once and goes out | Poor contact, protection board acting | Steps 3, 4 |
| Shows charging but never turns green | Low current, aged cells, cold | Steps 5, 6 |
| Turns green immediately | Already full, or very high internal resistance | Steps 6, 7 |
| Charger clearly hot or smells | Charger fault or abnormal pack | Disconnect and stop using |
The seven checks
Step 1 — Confirm the outlet and cable
Try a socket you know works, or plug a phone charger into the same one to verify. Power strips with a switch, travel adapters and car inverters are the usual sources of false alarms. On a USB charger, swap the cable and the plug too; broken cables are common.
Step 2 — Confirm the charger itself works
Put a known-good pack into the same charger. If it charges, the charger is fine; if neither responds, the fault is in the charger or its supply. Chargers that have been dropped, gotten wet or have loose prongs fail more often than people expect.
Step 3 — Check orientation and latch
Take the pack out and refit it, watching terminal direction and whether the latch seats. A pack that isn’t pushed home, or sits skewed, won’t meet the charger contacts and the light stays dark. Once it’s in, a gentle wobble shouldn’t produce movement.
Step 4 — Clean the contacts
Wipe the pack terminals and the charger’s spring contacts with a dry soft cloth or a pencil eraser to remove oxidation, sweat and dust. After seaside shoots or damp storage, contacts oxidize easily — a haze you can barely see is enough to block charging. Don’t use corrosive liquids or scrape with metal.
Step 5 — Come back to room temperature
Lithium cells pause charging when too cold or too hot, which is protection rather than failure. A pack just in from freezing weather needs half an hour indoors first; one left in a hot car needs to cool. Roughly 15–25°C is the comfortable range. Below freezing, capacity also drops sharply and charging efficiency suffers along with it.
Step 6 — Over-discharge from long storage
A pack ignored for a year or two has likely self-discharged to a very low voltage, and the protection board will refuse charge. Leaving it on the charger for a while sometimes works, as some chargers attempt a low-current wake-up. If there’s still no response after a long attempt, the cell is probably damaged — stop trying and replace it. The underlying fix is storage discipline: 40–60% charge and a top-up every three months. More detail in charging cycles and storage basics.
Step 7 — Decide whether it has simply aged out
If nothing above explains it and the pack is two or three years old, its life is likely spent. Lithium cells hold roughly 80% capacity after 300–500 cycles, and at that point both runtime and charging behavior get unreliable. Judge it by frames: noticeably fewer than when new — a third or more down — and it’s worth replacing.
Stop charging if you see these
- Swelling or deformation. Stop charging and discharging at once, then follow swollen battery safety steps.
- Hot to the touch while charging. Warm is normal, hot isn’t. Power down and inspect.
- Smell, smoke or leaking. Move it away from anything flammable, and don’t rinse a leak with water.
- A damaged charger. Loose prongs, cracked housing or exposed wiring mean retire it.
Replace rather than keep troubleshooting
Work down the list: physical damage means replace outright; charging faults with the charger ruled out mean consider replacing; clearly shorter runtime plus level jumping means replace; an occasional refusal that clears after cleaning means keep using it. Packs aren’t repairable, and opening a cell is genuinely dangerous — don’t attempt it.
If the body is showing an error at the same time, such as “cannot recognize this battery”, also read the recognition troubleshooting steps. The two problems sometimes share a cause.
FAQ
Red light after a full night — is the pack dead?
Not necessarily. Cross-check the outlet and charger first, then consider high internal resistance slowing the charge. If the charger now takes much longer to turn green than it used to, the pack is aging.
Can I charge an NP-FZ100 from a power bank?
Yes, provided the charger accepts USB input and the spec matches. Keep it off heat sources and don’t record for long stretches while charging.
Is it normal for a new pack not to charge?
No. Confirm the model is right and there’s no film on the contacts, then try a different charger. Still nothing means contact the seller for a replacement.
How often should I top up packs in storage?
About every three months, held at 40–60% charge in a cool, dry spot around 15–25°C. That keeps over-discharge risk low.
If the checks point to replacement, it’s cheaper to buy once and buy enough: 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 dealers restocking in volume should use wholesale inquiry — orders above 100 units are quoted by batch.