NP-FZ100

“It does not last like it used to” is a real effect, not imagination. Lithium cells lose capacity with both cycle count and calendar time, and they typically hold around 80% of rated capacity after 300–500 cycles. A noticeable drop after a year sits well inside expectations, and by roughly two years replacement deserves a serious look. What matters is telling slow, natural decline apart from a sudden drop: the first is ageing, the second usually traces back to deep discharge, long storage at full charge in heat, or a faulty cell, and the two call for different responses.

How the Loss Happens

Charging and discharging drive irreversible side reactions in the electrode materials. Usable lithium ions are gradually consumed and internal resistance climbs. That shows up as two effects: less energy goes in (capacity falls) and voltage sags faster under load (resistance rises). The second is usually what you notice first. You read it as “the battery drains fast” when capacity may only be down by a small margin — the resistance is what makes the body decide it is empty early.

• Normal use: the curve is fairly flat early on, then steepens.
• Frequent deep discharge: running to zero each time speeds up the decline.
• Long storage at full charge in heat: the most damaging combination there is — a full pack left in a car in summer, for example.
• Left flat in a drawer: a pack that self-discharges to nothing and stays there can be ruined outright.

Rough Capacity by Stage of Life

Stage	Approximate capacity	What it feels like
Under six months, few cycles	Close to rated	Stable, in line with 60–80% of the official figure
Around a year, regular use	Roughly 80–90% of rated	Slight decline; a single day’s shooting still fine
Around two years, 300–500 cycles	Around 80% of rated	High-intensity days need an extra pack
Three years and beyond	Possibly well below 80%	Fast drain, jumping gauge, occasional shutdowns

These are rough bands. Usage frequency, charging habits and storage conditions move the curve up or down quite a bit, so do not read your own pack into a row too literally.

Four Signals That Say Replace It

• Runtime clearly shorter than another pack of the same rating, confirmed by swapping packs in the same body.
• Shutdown at power-on or mid-burst, with the body coming back after a rest — the classic voltage-sag signature; diagnostics are in sudden shutdown and ageing checks.
• A gauge that jumps from two bars to shutdown, and still does after one recalibration cycle.
• Noticeably hotter than packs from the same batch, or any swelling in the shell, which means stop using it immediately.

Replacement Timing by Shooting Style

• Casual shooter: a pack lasts around two years. Replace it when it will not cover a day, and two in rotation is usually enough.
• Weddings and commercial work: rotate proactively at roughly eighteen months, and never take a pack you are unsure about to a paid job.
• Video creators: long takes are sensitive to internal resistance, so decline shows up earlier. Pair fresh packs with a dummy battery and AC adapter for any long fixed-position take.
• Studios and rental houses: keep a log of numbering and purchase dates, replace by batch, and avoid mixing packs at very different states of health.

Slowing the Decline

• Top up when convenient rather than running to zero each time.
• Store long-term at roughly 40–60% charge, cool and dry at about 15–25°C, with a top-up every three months — details in storing batteries you are not using.
• Avoid leaving packs at 100%, especially somewhere warm.
• Number packs and rotate them so none sits idle long enough to over-discharge.
• Charge somewhere ventilated so heat does not build up.

Replace One, or Replace Both?

If your packs were bought together, they have aged together, and when one stops covering a day the other is usually close behind. In that case replacing both at once is less hassle and it avoids the confusion of running mixed-health packs with different expectations. Sizing comes down to what one shooting day actually consumes, and the kit-versus-separate arithmetic is in why kits usually cost less.

FAQ

Is 80% capacity still usable?

Yes — it just means shorter runtime, so carry a spare or swap earlier. Jumping gauge readings, shutdowns or swelling are the point where you stop using it.

Only six months in and it already feels short. Normal?

Rule out settings, cold and gauge inaccuracy first. If those are cleared and it is still clearly short, you may simply be shooting hard, or the pack itself may be faulty — worth raising with the seller.

Can I mix old and new packs?

You can, but plan around the weaker one. Size your carry count on the worst pack in the bag, not the best.

What do I do with the old packs?

Keep serviceable ones as backups or for light duties. Anything swollen, deformed or leaking goes to hazardous waste collection — do not puncture or burn it.

Replacement costs less than people expect. YO’s NP-FZ100 compatible battery is rated around 2280mAh / 7.2V / 16.4Wh: about $17.89 for a single pack, about $22.93 with one charger, about $36.74 for two batteries and a charger. For more capacity, the TNP-FZ100 at 2400mAh / roughly 17.3Wh starts at about $19.66 for a single pack. Studios and rental houses replacing by batch should go through wholesale enquiry, where orders over 100 units are quoted per batch.

Start with what the light is doing. Completely dark usually points at the supply side: outlet, cable or the charger itself. Flashing red, or a light that never turns green, usually points at the battery side: poor contact, a deeply discharged pack, age, or temperature. Steady green means either full or an empty bay on standby. Colour conventions are not standardised across brands, so treat this as the common pattern and your own manual as the authority. The checking order stays the same: supply first, then contact, then the pack.

Common Indicator States

Light	Usual meaning	Check first
No light at all	No power	Outlet, cable, charger plug seated properly
Steady red	Charging (constant current / constant voltage)	Nothing — wait for it to turn green
Flashing red	Poor contact, pack fault, or over temperature	Reseat the pack, clean contacts, let it cool
Steady green	Full, or standby with no pack fitted	Confirm the pack is actually in the bay
Alternating red and green	Abnormal voltage or pack not identified	Fit a different pack to see which is at fault
Flashes once, then goes dark	Protection trip or internal fault	Test with another outlet and another pack

One trap worth knowing: some chargers show green before any pack is fitted, which is standby, not “full”. To confirm charging is really happening, check whether the pack warms slightly after a while, or watch for the colour to change.

No Light: Three Supply Checks

• Outlet: try a socket you know is live, or plug a phone charger into the same one. Ruled out the socket and any switched strip in one go.
• Cable: with a detachable mains lead or USB cable, swap in one you know works. Loose connectors and broken inner cores are common.
• Charger: look for scorch marks, smell or bent prongs, then fit a different pack. On a multi-bay unit, try another bay — if one bay stays dark while the rest work, that bay is the fault.

Flashing Red or Never Going Green: Four Battery Checks

• Reseat it: take the pack out, confirm orientation, push it fully home, and put it back. Not seated properly is the most common cause by a distance.
• Clean the contacts: wipe the pack terminals and the charger springs with a dry soft cloth, or rub lightly with a pencil eraser, to remove oxide, sweat and dust.
• Correct the temperature: a pack just in from the cold, or one already hot on charge, can trip protection. Let it sit at room temperature for ten minutes or so and try again; heat limits are in charging heat and safety limits.
• Compare with another pack: fit one you know is good. If that charges normally, the original pack is the problem — deeply discharged or aged. If the new one flashes too, it is the charger.

A pack left in storage long enough to self-discharge deeply may be refused outright. If there is still no response after a few minutes of a flashing light, retire the pack rather than coax it.

Green Light, but the Pack Is Empty

That means the charger is not seeing a load, and the usual reason is no contact: bent springs, a pack not pushed home, film or dirt on the terminals. Press lightly on the pack to see whether contact is made, or measure the voltage with a multimeter if you have one. If other packs charge fine in the same unit, the terminals on that one pack are the issue.

When to Replace the Charger

• Still completely dark after you have swapped outlet, cable and pack.
• One bay permanently dead while the others work.
• Hot shell, smell or noise during charging.
• Fill times that are wildly off, or packs that come off “full” and die quickly.

When replacing, make sure the charger actually matches the pack spec; the buying criteria are in how to choose an NP-FZ100 charger. If the pack itself will not take a charge either, work through the seven-step charging fault checklist.

Good Everyday Habits

• Charge on a ventilated, hard, flat surface. Not a bed, not a camera bag.
• Wait for green before pulling the pack. Do not keep interrupting the cycle.
• Store long-term at roughly 40–60% charge and top up every three months.
• Pack the charger and cable separately when travelling, so the prongs do not get bent.
• Leave space between packs on a multi-bay charger so heat does not stack.

FAQ

Red never turns green, even after hours

Check whether the pack is unusually hot first. If it is merely slow, a large pack on a low-current charger will take its time. If it is several times the normal duration and the pack is clearly hot, cut power and try a different charger.

Green with no pack, red once I fit one — normal?

Normal. Red means charging has started. Once it goes green, the pack is ready to use.

The light blinks a few times and goes out

Usually a protection trip. Take the pack out, check the shell for swelling, clean the contacts and retry. If it keeps happening, stop using that pack.

Can I mix charger and battery brands?

Physically, a matching form factor usually works, but pick products with clearly stated specs that are designed for the pack. Matching voltage and connector is the minimum requirement.

Rather than decoding an old charger’s light language, use a matched kit. YO’s NP-FZ100 compatible battery is rated around 2280mAh / 7.2V / 16.4Wh: about $17.89 for a single pack, about $22.93 for one battery with a charger and about $36.74 for two batteries with a charger — the charger effectively adds roughly $5, which is hard to beat shopping for one separately. The TNP-FZ100 is the 2400mAh / roughly 17.3Wh version. Restocking in volume goes through wholesale enquiry, where orders over 100 units are quoted per batch.

When a body starts shutting down and a full pack lasts half as long as it used to, the usual cause is an aged battery, with body settings and environment coming second. Work in this order: rule out settings and environment first, run one full cycle to recalibrate the gauge, then swap in a known-good pack to see which side the problem sits on. If several packs all run short in the same body, look at the body. If only one pack runs short, that pack has aged.

Rule Out Three Non-Ageing Causes First

• Cold: capacity drops noticeably below freezing, and around -10°C you may get roughly half of what you would at room temperature. Fast drain in winter usually recovers once the pack warms up; the coping strategy is in winter runtime.
• Power-hungry settings: a bright screen for composing, burst shooting, 4K recording, constant autofocus and playback all raise draw, so the frame count falls accordingly. Drop the screen brightness and cut playback for a day and see whether the numbers come back.
• An inaccurate gauge: a jumping percentage makes it look like runtime collapsed. Do one full charge-and-discharge cycle before you judge anything; the method is in calibrating the charge display.

Six Signs of an Aged Pack

Symptom	Likelihood of ageing	What it means
Drops to one bar after a few dozen frames from full	High	Usable capacity is well below the rating
Jumps from two bars straight to shutdown	High	Discharge curve collapses at the end; resistance is up
Cuts out at power-on or during a burst	High	Voltage sags under load and trips protection
Runs clearly hotter than packs from the same batch	Medium-high	Rising resistance produces more heat
Charges suspiciously fast, then dies just as fast	High	It is accepting less energy in the first place
Swollen or deformed shell	Safety issue	Stop using it and handle it as a safety issue

Note how the first, third and fifth rows combine. A pack that charges fast, empties fast and runs hot is aged, and you can treat that as settled.

How to Locate the Problem With a Swap Test

• Swap the pack: fit a known-good battery into the same body. If runtime returns to normal, the original pack was the problem.
• Swap the body: put the suspect pack into another body of the same model. If it still runs short, it is the pack.
• Change the conditions: test indoors at room temperature with the power-hungry settings off, to remove cold and settings from the equation.
• Count frames: log the shot count for two packs across the same outing. A written comparison beats an impression.

You do not need to-the-frame precision. You only need to see whether one pack is clearly behind the other. Official CIPA figures usually sit in the 500–700 frame range, while real-world use commonly lands closer to 60–80% of the rating, and lower again for video and bursts.

How Much Life Is Left: The Ageing Curve

Lithium cells typically retain around 80% of their capacity after 300–500 cycles, so “shorter after a year” is expected rather than alarming, and by roughly the two-year mark replacement deserves serious thought. Charging two or three times a week puts most people at that point somewhere between a year and a half and two years; heavier users arrive sooner. The full curve is laid out in capacity loss and replacement timing.

Situations Where You Should Just Replace It

• Ahead of a wedding, commercial shoot or trip, when one pack is clearly underperforming.
• Shutdowns during bursts or recording that have already cost you frames.
• Obvious heat while charging, or any swelling in the shell.
• Two-plus years of service, or cycle count approaching 300–500.

Heavy users should keep at least two packs in rotation so no single pack becomes the single point of failure in a shoot.

Habits That Slow Ageing

• Top up opportunistically rather than running to zero. Frequent deep discharge is hard on cells.
• Store long-term at roughly 40–60% charge, cool and dry at about 15–25°C, with a top-up every three months.
• Avoid leaving packs at 100%, especially in a hot place.
• Number your packs and rotate them, so none sits idle long enough to self-discharge into trouble.
• Keep terminals clean and dry. Wipe them down after coastal or wet shoots.

FAQ

It shuts down, then powers back up showing charge. Is the pack dead?

Probably aged. Start-up and burst shooting draw high current; voltage sags under that load and trips protection, then recovers once the pack rests. That rebound is a classic ageing signature.

Can a new pack shut the camera down too?

Yes, under high load in burst or 4K, or in the cold. Warm it up and retest at lower load. If it still cuts out in normal conditions, contact the seller.

Will recalibration bring capacity back?

No. A full cycle improves the accuracy of the display, not the energy the cell holds. If the real frame count is still short afterwards, the cell has genuinely degraded.

Can the body itself cause shutdowns?

It can. Firmware glitches, a heavy lens focus motor, or heat protection in hot weather can all shut a body down. Use the swap test to separate the two.

Replacement is cheaper than most people assume. YO’s NP-FZ100 compatible battery is rated around 2280mAh / 7.2V / 16.4Wh: about $17.89 for a single pack, about $22.93 with one charger, about $36.74 for two batteries and a charger. If you want more headroom, the TNP-FZ100 is the 2400mAh / roughly 17.3Wh version, and long wedding days are worth planning around two or three spares per body. Bulk replacement goes through wholesale enquiry, where orders over 100 units are quoted per batch.

Direct answer: a mildly warm NP-FZ100 on charge is normal; too hot to hold for more than a second or two is not. Charging a lithium cell is an energy conversion, and some of that energy leaves as heat, especially during the bulk phase where current is highest. A rough hand test: if the pack feels warm and you can keep it against your palm, that is within the normal range. If you pull your hand away, or the charger shell is too hot to touch, cut the power and investigate. These are practical guidelines rather than a measured temperature standard — your own product documentation and common sense come first.

Where the Heat Comes From

• Conversion losses: cell internal resistance turns part of the incoming energy into heat during constant-current and constant-voltage charging. This cannot be avoided entirely.
• Charge current: higher current fills the pack faster and produces more heat per minute. A multi-bay charger running several packs at once runs warmer overall.
• Ambient conditions: a hot room in summer, or a pack charging inside a camera bag or under a blanket, has nowhere to dump heat, so it accumulates.
• Ageing: as a pack approaches roughly 300–500 cycles, internal resistance rises, so the same current produces more heat than it did when new.

So “hot while charging” covers two very different situations: a new pack on a ventilated desk, and an old pack sweating inside a closed bag.

Hand Test: Where Normal Ends

How it feels	Likely state	What to do
Barely warm, just above room temperature	Trickle stage or about to go green	Normal. Let it finish
Warm, comfortable against your skin	Typical mid-charge condition	Normal. Keep it ventilated
Hot enough that you want to let go after a few seconds	High, worth checking	Unplug, let it cool, check charger and placement
Too hot to touch, with smell, noise or case deformation	Fault, safety relevant	Cut power, move it to open space, stop using it

Hand feel is subjective and depends on room temperature. When in doubt, change one variable: a different charger in a different spot. If it runs noticeably cooler, the original charger or its location was the problem.

Six Ways to Keep Charging Temperatures Down

• Charge on a hard, flat, ventilated surface. Not carpet, not a bed, not inside a camera bag.
• Keep it out of direct sun and away from radiators and hobs. A warm room stacks on top of charging heat.
• Do not chase speed with high current. Routine-rate charging is kinder to cells.
• Leave space between packs on a multi-bay charger. Do not stack chargers or cover them.
• A pack straight out of the camera is already warm. Give it a few minutes before it goes on the charger.
• Let the charger reach its green “done” state before pulling the pack, instead of interrupting the bulk phase repeatedly.

Signals That Mean Stop Immediately

• Swelling, deformation or a case splitting at the seam — stop using it and do not charge it again; handling is covered in what to do with a swollen battery.
• Burning smell, smoke or unusual noise — cut power, move the pack to a clear dry area away from anything flammable.
• A charger that is itself too hot to touch, discoloured or scorched — retire that charger and check the spec matched.
• Charge level that goes backwards, or a pack that never finishes — swap the charger and the pack one at a time to isolate which is at fault.
• A pack that is full and then flat within minutes, or shutdowns mid-shoot — that points at a worn cell rather than a charging fault.

Heat Outside of Charging

Batteries also warm up in the camera during long video takes and fast burst shooting. That is discharge-side heat, different from charging heat but worth the same attention. If the body is clearly warming during continuous 4K, rotate packs so each one gets a cooling break, or move to a dummy battery with an AC adapter. The options are set out in uninterrupted power for video and streaming. Cold is the opposite problem: a chilled pack loses usable capacity, and the fix starts with keeping spares in an inside pocket.

Two Safety Notes

First, do not put a pack in the fridge or cool it with water to make it “less hot”. Condensation risk outweighs any benefit. Second, when buying, look at cell spec, protection circuitry and whether the charger actually matches — that reduces heat problems far more reliably than shopping for a slower charger. The reasoning is in third-party battery safety.

FAQ

A brand-new pack runs hot on its first charge. Is it faulty?

Rule out environment and charger first: move it to a ventilated desk, then try a different charger. If it still runs clearly hot, ask the seller for a replacement and do not open the pack yourself.

Does charging heat damage the cells?

Sustained high temperature accelerates capacity loss. Occasional warmth has limited effect, but storing a pack full in a hot place will age it noticeably faster.

Does it keep heating if I leave it plugged in?

Heat drops off once charging reaches the trickle or done state, but leaving a pack at 100% indefinitely is not a good habit. Take it off the charger when it is done, and store long-term at roughly 40–60%.

Is fast charging worse than slow?

High current runs hotter and has a small long-term effect on ageing. Use routine current when you are not in a hurry, and save fast charging for when you are.

A matched charger removes most of the guesswork. YO’s NP-FZ100 compatible battery is rated around 2280mAh / 7.2V / 16.4Wh, at about $17.89 for a single pack, about $22.93 for one battery with a charger and about $36.74 for two batteries with a charger — the bundled charger is specified for these cells. The TNP-FZ100 is the 2400mAh / roughly 17.3Wh alternative. Studios and rental houses kitting out batteries and chargers together should go through wholesale enquiry, where orders over 100 units are quoted per batch.

Short answer first: the “not genuine” style warning you get with a third-party NP-FZ100 is normally just a disclosure about charge display accuracy. It does not affect power delivery and it does not affect shooting, so you can carry on using the pack. Some Sony bodies phrase it as “the remaining charge may not be displayed accurately”. What it really means is that the body cannot fully confirm the discharge curve of a non-original pack, so it will not vouch for the percentage. The wording that should worry you is different: “cannot recognise this battery” or “this battery cannot be used”. That means the body is refusing to draw power, and it goes down the fault-finding path instead.

What Each Message Actually Means

Body message	Nature	Can you keep shooting?	What to do
Remaining charge may not be displayed accurately	Standard disclosure	Yes	Nothing. Swap at one bar instead of waiting for empty
Not genuine / non-original battery notice	Identified as third-party	Usually yes	Confirm the spec matches, then carry on
Cannot recognise this battery / use a compatible battery	Communication or power fault	No	Work through the not recognised troubleshooting steps
Battery exhausted / replace the battery	Voltage below the working threshold	No	Fit a charged pack

The test that matters is simple: can you shoot? If the camera powers on, fires and plays back, the message is informational. If it will not run at all, that is a fault, not a disclaimer.

Why the Warning Appears at All

Modern camera batteries carry a communication chip. The body reads data off that chip to estimate the remaining percentage. An original pack has a cell curve and internal-resistance profile that is fully modelled in the body firmware, so the readout tracks well. A third-party pack can match the spec sheet and still discharge slightly differently. With no matching curve in firmware, the body takes the conservative route and tells you the number may be off.

The important distinction: this is a communication and identification difference, not a power delivery difference. Whether a pack can drive the body depends on voltage, capacity and discharge capability, not on whether the firmware recognises the chip. The chip exists to report data back to the body; it does not gate how much current the pack can deliver.

Three Practical Effects on Shooting

• Runtime is unaffected: real shot count comes from capacity and body power draw, not from the message. A pack rated around 2280mAh / 16.4Wh still delivers what its capacity allows.
• The percentage may drift: slow to fall at the top, quick at the bottom, or a jump from two bars straight to shutdown. That is the inaccuracy being described.
• A few functions may behave differently: a small number of bodies want extra battery data in certain modes. If something refuses to run, test once with an original pack to see whether the battery is the variable.

If the drift is obvious, one full charge-and-discharge cycle usually tightens it up. A full discharge followed by one uninterrupted charge usually pulls the readout back into line.

When the Warning Deserves Attention

• Runtime is clearly shorter than a comparable pack — possibly overstated capacity or a worn cell.
• Full-to-empty time swings wildly, or the body shuts down repeatedly mid-shoot.
• The wording escalates from “may not display accurately” to “cannot recognise”, which points at contacts or model mismatch.
• The pack is swollen, deformed, or hot to the touch while charging — stop using it.

You can sanity-check capacity with one full cycle and the body’s own shot count: if one pack is clearly behind another of the same rating, the cell is the likely cause.

Keeping Display Drift to a Minimum

• Buy a spec-matched pack with a communication chip and clear capacity and voltage markings.
• Run two or three full cycles on a new pack so the body can relearn the curve.
• Store long-term at roughly 40–60% charge and top up every three months.
• Keep terminals clean and dry. Oxidation raises the odds of flaky communication.
• Rotate several packs instead of leaving one idle for months, which lets its curve drift.

FAQ

Can this warning damage the camera?

There is no evidence that the notice itself harms a body. What can cause harm is a poor cell with mismatched voltage or spec, which is why the buying decision should be based on spec, not on whether a warning shows up.

Can I turn the warning off?

Most bodies have no such option, and blocking it by unofficial means is not advisable. Treat it as a reminder that the percentage is indicative.

Does runtime get shorter once the warning appears?

No. Runtime follows capacity and power draw. A pack that feels shorter is usually worn or cold; the ageing curve is set out in capacity loss and replacement timing.

Do original packs never drift?

They generally track better, but an aged original jumps too. Around two years in, or after roughly 300–500 cycles, any pack can start misreporting.

Clean specs and a communication chip cut most of this friction. YO’s NP-FZ100 compatible battery is rated around 2280mAh / 7.2V / 16.4Wh, at about $17.89 for a single pack, about $22.93 with one charger, and about $36.74 for two packs and a charger; the TNP-FZ100 is the 2400mAh / roughly 17.3Wh version. For the wider picture, original versus third-party compared lays out the trade-offs. Studios and rental houses buying in volume should go through wholesale enquiry, where orders over 100 units are quoted per batch.

A new NP-FZ100 that refuses to go in is rarely a dead battery. In most cases it is one of three things: wrong model, wrong orientation, or a protective film still on the terminals. Start by confirming the body belongs to the FZ100 family. A7 III, A7R III/IV/V, A7 IV, A7S III, the A9 series, A1, A6600, A6700, the A7C series, FX3, FX30 and ZV-E1 all run on this pack. A6400, A6500, A6300, A7 II, A7R II and A7S II take the NP-FW50, which looks broadly similar but physically will not seat. Once the model is right, work through orientation, latch, then contacts. Most cases resolve in a minute or two. Do not press hard.

Step 1: Make Sure You Bought an NP-FZ100

This is the most common cause. Plenty of orders get placed under a generic “Sony mirrorless battery” listing and arrive as an FW50 or a BX1. The three families differ in size, capacity and latch position, and they cannot be swapped. The full cross-reference lives in Sony mirrorless battery comparison chart, and the body-by-body list is in every camera that takes the NP-FZ100.

• NP-FZ100: most full-frame and flagship bodies from the A7 III onward, rated around 2280mAh / 7.2V / 16.4Wh.
• NP-FW50: earlier bodies such as the A6000, A6300, A6400, A6500, A7, A7 II, A7R II and A7S II.
• NP-BX1: compact cameras like the RX100 series.

One more naming trap worth knowing: TNP-FZ100 is the 2400mAh variant. Its shell and latch are identical, so it drops into the same bodies — the difference is the cell rating, not the fit.

Step 2: Check Orientation and Latch Position

The NP-FZ100 is directional. The front face usually carries an arrow or a body diagram; the terminal side goes inward, and the side with the latch notch lines up with the spring catch inside the compartment.

• Open the compartment door fully and look at which way the contacts inside face.
• Terminals inward, label outward. Push straight along the rails, not at an angle.
• You should hear a faint click at the end of travel — that is the catch engaging.
• If the tail of the pack sits proud, it is not seated. Take it out and start over rather than closing the door against it.

Reversed, the pack simply will not go in. That is the point to stop pushing: forcing it can bend the spring contact in the compartment or scratch the terminal plating.

Step 3: Check for Terminal Film and Packaging Residue

Some packs ship with a thin transparent film or plastic strip over the terminals for short-circuit protection. It is close in colour to the contacts and easy to miss. Hold the pack up to the light before loading and confirm the metal is fully exposed, with no film and no adhesive residue. Film in place means no power, and the body may report that it cannot read the battery.

Step 4: When the Latch Feels Too Tight

A fresh pack with tight shell and latch tolerances is normal, and it usually loosens up after a few cycles.

• To insert: push the pack all the way in, press with the flat of your finger near the tail by the latch, and release once you hear the click.
• To remove: flick the release lever inside the compartment first. The pack will lift slightly on its own, then pinch and pull it out. Do not dig into the side of the pack and yank.
• Door will not close: the pack is not seated. Take it out, reload it, and check the compartment for debris or a bent spring.
• If the catch is genuinely stiff, a trace of dry lubricant on the plastic edges away from the terminals can help. Work it in with a few insert-and-remove cycles. Keep it off the contacts.

Step 5: Inspect the Pack and the Compartment

Look over the shell for swelling, deformation or flashing on the moulding, and check whether the terminals sit straight. Then look inside the compartment for debris and for a spring contact that is bent or loose. A swollen pack must never be forced in — set it aside and handle it as a safety issue. A visibly deformed spring is a body-side fault and belongs in a service centre, not in a battery replacement.

Three Checks Once It Is In

• Power on and confirm the charge indicator appears normally instead of a “cannot be used” message.
• Fire off a few frames and check that playback is clean.
• Charge it fully before the first outing rather than heading out on shipping charge.

If a full pack drains quickly, or the gauge drops from two bars straight to shutdown, a full charge-and-discharge recalibration usually helps. The procedure is in fixing an inaccurate charge display.

FAQ

The pack goes in but will not latch and pops out when touched

Usually the catch has not engaged, or the compartment catch is worn. Make sure you push to the end and hear the click. If it keeps happening, check the latch notch on the pack for flashing and ask the seller for a replacement if needed.

It is in but the camera does nothing — is it reversed?

Reversed, it would not have gone in. No power at all is more likely film on the terminals, dirty contacts or a flat pack. Charge it, wipe the contacts with a dry cloth, and try again before assuming a fault.

I forced it once. Can that damage the camera?

One light squeeze is unlikely to cause damage, but check the compartment contacts for deformation and the pack shell for cracks. Watch for “not recognised” messages or odd shutdowns over the next few shoots.

I have two packs and one is smooth while the other is tight

Batch tolerances vary and that is normal. The tighter one usually improves with use. As long as it latches and delivers stable power, it is fine.

If the model was simply wrong, reorder against the FZ100 spec. YO’s NP-FZ100 compatible battery is rated around 2280mAh / 7.2V / 16.4Wh: about $17.89 for a single pack, about $22.93 for one battery with a charger, and about $36.74 for two batteries with a charger. If you want more capacity, the TNP-FZ100 is the 2400mAh version at roughly 17.3Wh. Studios and rental houses kitting out in volume should go through wholesale enquiry, where orders over 100 units are quoted per batch.

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.

Direct answer: a swollen NP-FZ100 is done. Don’t use it, and don’t charge it. Swelling means gas has formed inside the cell and the internal structure is no longer stable. Further charging or discharging risks more expansion, leaking, or thermal runaway. The correct response is to stop using it, insulate the terminals, store it alone, and hand it over to a battery or hazardous waste collection point. The price of one pack is far below the cost of one incident, and this isn’t a place for optimism.

How to tell whether it’s swollen

Mild swelling isn’t always obvious to the eye. These checks will confirm it:

• The spin test. Set the pack on a flat table or a piece of glass and give it a gentle push. If it spins or rocks freely, the underside is no longer flat.
• Look at the seam. Is the case seam opened up, or do the sides bulge so the middle sits higher than the edges?
• How it fits. Noticeably tight going into the compartment, sticking on the way out, or a battery door that won’t close properly.
• How it feels. A hollow or slightly springy feel under light finger pressure, instead of the solid feel of a healthy pack.
• Companion symptoms. Sudden capacity loss, clear heat while charging, or the level jumping — all possible signs of internal trouble.

Any one of these is enough. Treat it as swollen and don’t wait for it to get more obvious.

Why packs swell

Cause	What happens	Preventable
Overcharging or failed charge control	Long overcharge, or a charger that doesn’t match the spec	Yes
Short circuit	Terminals touching metal, or an internal micro-short	Yes
High temperature	A car in summer sun, or long storage beside a radiator	Yes
Stored at full charge	Full charge plus heat accelerates gas formation	Yes
Deep over-discharge	Left unused without top-ups, cells take damage	Yes
Normal aging	Wear sets in after roughly 300–500 cycles	Only slowed
Physical damage	Drops, crushing, puncture	Yes

Almost every cause traces back to use and storage habits. Even a dropped pack that looks fine deserves an observation period before you trust it on paid work.

What to do once you find one

• Step 1: stop using it. No camera, no charging, and don’t try to drain it.
• Step 2: remove it. If it’s stuck in the compartment, don’t pry or force it — rock gently or use tape to pull, without squeezing the cell.
• Step 3: insulate the terminals. Tape over the contacts, or use the original packaging or a cap, so they can’t meet keys or coins.
• Step 4: store it alone. Dry, cool and away from anything flammable. Don’t stack it with other packs.
• Step 5: never puncture, crush or burn it. All of these can start a fire. Don’t put it in general trash either.
• Step 6: take it to a collection point. Hazardous waste facilities, electronics markets and retailer battery drop-offs, following local rules.
• Step 7: check the rest of the batch. Inspect other packs from the same set and the same charger, and retire them together if needed.

If a pack is smoking, clearly hot or smelling, move people and flammables away, keep the area ventilated and follow local emergency guidance.

Preventing the next one

• Use a charger that matches the spec on voltage and interface. Cheap chargers without protection circuitry carry more risk.
• Avoid sitting at full charge. If you’re not shooting for a few days, bring packs down to 40–60% rather than leaving them on the charger.
• Control temperature. Store around 15–25°C. No packs in a sunlit car, none beside a heater.
• Avoid over-discharge. Top up every three months in storage — see charging cycles and storage basics.
• Prevent shorts. Terminal covers or individual slots; no loose packs sharing space with metal objects.
• Don’t drop or crush them. Keep batteries in their own pouch, not under heavy gear at the bottom of a bag.
• Inspect routinely. A glance at each pack before and after a shoot catches problems early.

More on third-party pack safety in are aftermarket camera batteries safe; if the pack also shows recognition errors, the recognition troubleshooting steps applies.

FAQ

Can I keep using a slightly swollen pack for a while?

We wouldn’t. Swelling is irreversible and progresses unpredictably — especially not on a job that matters.

Can I fly with a swollen battery?

No. Lithium cells in an abnormal condition aren’t permitted on aircraft, in the cabin or in checked bags. Dispose of it through a collection point instead.

Can I release the gas and carry on?

No. Puncturing or squeezing to vent gas destroys the internal structure and can cause a short and a fire. It’s a dangerous maneuver — never try it.

How do I tell swelling apart from a normal curved case?

A healthy pack sits flat and doesn’t rock on a tabletop. The spin test answers it in a second; if it rocks, treat it as swollen.

Replace what you retire and match stock to your shooting volume: 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 TNP-FZ100 (2400mAh, roughly 17.3Wh) at about $19.66 / $24.70 / $39.92 — pair either with a charger built to the same spec. Studios and rental houses cycling out aging packs on a schedule should use wholesale inquiry — orders above 100 units are quoted by batch.

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.

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.