SONY FZ100

Short answer: capacity fade in a lithium-ion pack like the TNP-FZ100 is gradual, typically falling to about 80% of rated capacity after 300–500 full cycles; whether to replace comes down to how many fewer frames it delivers in the same situation, and whether charging heat and charging time have visibly changed — you do not need to wait until it refuses to charge at all. The method below needs no instruments and no disassembly; ordinary shooting records are enough.

One thing to be clear about: this article will not give figures like “after X months it is at Y percent”. Fade correlates strongly with depth of discharge, ambient temperature, storage charge level and discharge current, so any single sample’s numbers say little about anyone else’s. What can be given is the mechanism, the ranges and reproducible checks.

How fade happens

Capacity loss in a lithium-ion cell comes mainly from three places: structural fatigue in the cathode material, progressive thickening of the solid electrolyte interphase on the anode, and slow decomposition of the electrolyte. All three accumulate with cycles and are accelerated by heat. For a 7.2V / 2280mAh / 16.4Wh specification like the NP-FZ100, the two most direct variables are depth of discharge and temperature.

Running the pack to auto-shutdown before recharging wears it noticeably faster than topping up at twenty or thirty percent. Equally, leaving packs in the car in summer, or dropping a hot camera straight into a sealed bag, steepens the fade curve early. That is why two packs bought in the same batch can be in quite different states a year later.

Because the TNP-FZ100 charges over USB-C with the charging circuit in the pack itself, the effect of long, hot charging is worth more attention than with a dock — if it feels hot in the hand while charging, switch to a gentler charger or move it somewhere with airflow.

Three checks that need no instruments

Method one: count frames in the same situation

Fix one scenario — the same event, the same burst ratio, the viewfinder used or not — and count the frames between a full charge and the low-battery warning. The number a new pack delivers in that scenario is your own baseline. Repeat every two or three months; if the figure falls below seventy percent of baseline, fade is affecting real use.

Do not mix numbers from different scenarios: LCD versus EVF, stabilisation on or off, and burst ratio can each move the count by twenty or thirty percent.

Method two: watch charging time and heat

Rising internal resistance accompanies fade. It shows up as a shorter charge from low to full — because less capacity is actually going in — but with more noticeable heat, concentrated in the middle of the pack. A distinctly shorter charge combined with a hotter shell than before usually means the fade is no longer slight.

Method three: look at the shape of the discharge curve

A healthy pack falls fairly evenly. One with obvious fade often holds steady and then plunges: from 30% straight to the warning, or losing a bar soon after coming off a full charge. That non-linear drop is typical of elevated internal resistance, appears earlier than the loss of total capacity, and reflects the real state more honestly.

When you must replace, and when you can keep it

The first two rows of that table are still usable; the last three are safety matters and should not be stretched. Swelling is the least negotiable signal — once a lithium pack has swollen, the internal chemistry is out of control, and continued charging carries a fire risk regardless of how much capacity is left.

How to slow the fade

• For long storage, leave the pack at forty to sixty percent rather than full or empty across the season. Full storage accelerates cathode ageing, and empty storage risks over-discharge and sleep.
• Avoid charging in hot places. A summer car or a sunlit windowsill is not suitable.
• There is no need to drain it flat every time. Shallow cycling is kinder to cycle life; lithium cells have no memory effect.
• Charge before you travel, not a week in advance. For cold and heat precautions, see our notes from minus ten degrees.

A rough guide by intensity: two or three shoots a week at one or two hundred frames each, and two or three years from a pack is normal; with daily high-rate bursts or long recordings you will notice faster drain in about eighteen months. On this measure the YO TNP-FZ100 behaves no differently from an original pack of the same specification.

FAQ

My new TNP-FZ100 seems to last less than the original — is it fading?

Usually not. A new pack has not faded appreciably; the difference is more likely in how the rated capacity is calibrated, in the body’s estimation strategy for third-party packs, and in the fact that you compared under different conditions. Run method one above in a fixed scenario for each, then judge. Body estimates of third-party packs are also often non-linear, so a low percentage does not necessarily mean little charge remains.

Can I measure capacity myself?

Roughly. Charge the pack from low to full on a USB charger that displays wattage, note the Wh delivered, and multiply by charging efficiency (usually estimated at 0.8–0.9) to work back to usable capacity. The method has preconditions: the same starting charge, a similar ambient temperature, and an accurate readout on the charger. The error is not small, so it is good for trends, not for firm conclusions.

Must I replace at 80%?

Not necessarily. Eighty percent is the conventional threshold used to describe cycle life in the industry, not a threshold for use. If your workload is modest and the situations are controlled, a pack at eighty percent still works as a spare. The real dividing line is whether it still affects your shooting rhythm, and whether swelling or abnormal heat has appeared. The rules for flying with batteries are in this guide, and they apply equally to a faded pack.

Two packs bought together — why do they fade at different rates?

The usual reason is different intensity of use: one sits in the main camera and is often run deep, the other only comes out occasionally. Next is charging habit, for instance one regularly on a high-power charger and the other on an ordinary one. Number the packs and rotate them, and their fade will converge.

Short answer: the TNP-FZ100 is an NP-FZ100 replacement with a USB-C port built in. The charging circuit lives in the pack itself, so a phone charger or a power bank will top it up without Sony’s BC-QZ1 dock. The shape, contacts and mounting follow the NP-FZ100 specification, so it drops straight into the bay of the A7 III/IV, A7R III/IV/V, A7S III, the A9 series, the A6600 and the FX3. The differences from the original are not about whether it works, but about five practical things: the charging path, accessory cost, the charge readout, capacity expectations and after-sales. Each is set out below, so you can decide whether those differences are worth a different way of working.

Difference one: the charging inlet moved from the dock to the pack

The original NP-FZ100 is rated 2280mAh / 16.4Wh / 7.2V and has two conventional ways to charge: on the BC-QZ1 single-slot dock, or inside the camera through its USB-C port, slowly. The first needs an extra accessory; the second ties up a camera body, which cannot leave the wall while it charges.

The TNP-FZ100 adds a Type-C port on the side of the pack, which creates a third route: take the battery out, connect it to any 5V USB source, and charge. On a trip, two packs and one cable are lighter than a dock and freer than leaving the camera tethered to a wall.

One point is easy to misread: that Type-C port only works when the pack is out of the camera. Once seated in the bay the connector is covered, and any charging then runs through the body’s own USB-C input — a camera function, entirely separate from the port on the battery. For how long body-powered operation can last, see our piece on dummy batteries and continuous power.

Difference two: what you save is a whole charging kit

People who use original batteries usually carry a dock, a dedicated cable and one pack that is flat because they forgot to charge it. The TNP-FZ100 reduces that to an ordinary USB-C cable: a phone charger, the USB socket in the car, a power bank in your bag — any of them is a supply.

The cost difference is more concrete. The BC-QZ1 is sold as a separate accessory, and the TNP-FZ100 needs no matching dock, which removes that expense outright. Several packs can share the same phone charger, though charging them at once needs a multi-port charger or a splitter, and the speed falls with the divided current.

Difference three: the readout is usually normal, but there are body limits

Most NP-FZ100 bodies display the percentage normally with a third-party pack installed, and the camera will not refuse to start because you changed the battery. This is reliable on newer bodies such as the A7 IV and A7S III, because the body reads what the battery management chip reports rather than what is printed on the label.

The limit is firmware. Several Sony body updates have adjusted battery recognition logic, and particular versions may show a prompt at power-on or shut down early at low charge. If you have a specific body and firmware combination, the prudent approach is to buy one pack, confirm that the discharge curve and shutdown point suit how you shoot, and then decide whether to fill out the kit.

Low temperature is another detail. The rise in internal resistance below freezing is not identical to the original, so the fade curve differs; our field test at minus ten degrees records the specifics.

Difference four: keep capacity and cycle-life expectations realistic

The original’s 2280mAh is a rating, and usable capacity varies with discharge rate and temperature. The TNP-FZ100’s rated capacity is the figure on its packaging, and real-world shot counts usually land between 400 and 600, depending on whether you use the viewfinder, shoot bursts and review often. That range is in the same bracket as the original, but it is unwise to expect an identical result.

On cycle life, third-party packs typically lose capacity a little more visibly than the original after 300 full cycles. For a photographer shooting two or three hundred frames a day, that difference takes two or three years to show; for someone recording video daily and fully cycling the pack each time, the replacement interval will be shorter.

Difference five: a different after-sales route, and a different way of topping up

Original batteries go through Sony’s warranty system: an official channel and a clear process, but a long turnaround and a high cost. The TNP-FZ100 goes through the brand’s own support, where the advantage is a low replacement cost — if it fails, a straight swap is cheaper than a repair, and better suited to a workflow that treats batteries as consumables.

The topping-up habit changes with it. Instead of queueing packs on a dock one at a time at the end of the day, you can fill them in the car between locations, in a café, or from the same port that is charging your phone. For multi-camera and long exterior work, that change matters more than any number on a spec sheet.

FAQ

Will the TNP-FZ100 fit the A7 II?

No. The A7 II and the first-generation A7 use the smaller NP-FW50, with a different bay size and different contacts. The NP-FZ100 became the main specification from the A7 III and A7R III generation, and the A6600, A7S III, FX3 and A9 series belong to the same family.

Will the camera show a non-genuine battery warning?

Most bodies do not prompt; they simply show the charge level. A few firmware versions may display a notice, or the percentage may jump more than with the original. If the notice interferes with use, try updating the body firmware, or keep that pack for a backup body where the prompt does not matter.

Do I have to use the original charger?

No. An ordinary 5V phone charger, a power bank or a car charger all work, and a higher input current charges faster. With a PD charger that supports higher voltage, the actual power depends on what the pack and the charger negotiate, and will not necessarily reach the charger’s rating.

Is one battery enough?

It depends on the work. One pack usually covers a day of stills; for video, at least two in rotation is advisable. If you want to top up while shooting, a dual-slot case or a spare direct-charge pack is more dependable than hunting for a socket at short notice. The model list is in our Sony FZ100 battery section.

Short answer: the TNP-FZ100 matches the original at 7.2V / 2280mAh / 16.4Wh, and one pack records roughly 120–150 minutes of 4K 30p, drops to 90–110 minutes at 4K 60p 10-bit, and only 55–85 minutes at 4K 120p or 8K; what sets runtime is total system draw, not the bitrate figure itself — bitrate is only an indirect indicator of it. Below is the estimation method, and a table of ranges by body and format.

One thing to state up front: every duration here is a range derived from a power model, not a measurement of a specific camera at a specific temperature. Usable cell capacity, the body’s thermal strategy, ambient temperature and whether lens stabilisation is working will all push the real result away from the estimate, and a drift of twenty to thirty percent is common.

The basic formula

A 16.4Wh pack is usually good for about ninety percent of its rating in practice — the body shuts down when voltage reaches a threshold rather than draining the cell flat. So usable energy is roughly 14.5–15Wh. Runtime in hours = usable Wh ÷ total draw in watts. Total draw covers sensor readout, image processor, encoder, screen or viewfinder, in-body stabilisation, card writing and the lens focus motor.

For example: at 8W total draw, 14.7 ÷ 8 ≈ 1.84 hours, or about 110 minutes. At 12W, only about 73 minutes. That is why going from 4K 30p to 4K 120p nearly halves runtime — the draw roughly doubles.

Runtime ranges by bitrate and format

The draw figures are estimates by body class and encoding load, not manufacturer-published values. Runtimes calculated from them typically land within ±20% of what you see in the field, which is enough for planning headroom on a shoot.

Why higher bitrate is not linear power draw

Many people assume that doubling the bitrate halves the runtime. It does not work that way. Bitrate affects the encoder load and the card write power, and those two are a limited share of the total. The bulk of the draw is sensor readout and image processing, which stay essentially constant at a given resolution and frame rate; a higher bitrate barely moves them.

So going from 100Mbps to 200Mbps may add 10–15% to the draw and cost you a dozen minutes; but going from 4K 30p to 4K 120p quadruples the frame rate, multiplies the work of sensor and processor, and nearly halves the runtime. When estimating, look at frame rate and resolution first, bitrate second — in the other order it is easy to get wrong.

The effect of codec

At the same bitrate, H.265 usually loads the encoder harder than H.264 but produces smaller files and less write pressure. All-Intra demands more sustained writing than Long GOP and draws a little more. These differences are generally in the half-watt to one-watt range, which over a two-hour recording adds up to a dozen minutes or so.

What eats into the estimate during real recording

• Thermal time limits: many bodies trigger a recording cap at high-frame-rate 4K once the camera gets hot, stopping automatically after twenty or thirty minutes. What is limiting you there is heat, not the battery. For continuous work, external power plus active cooling is the more dependable route — see our dummy battery power guide.
• Screen brightness and ambient temperature: a bright outdoor viewfinder in summer can add one to two watts on the screen alone; in cold weather lithium-ion activity drops and the same capacity yields less energy, so usable time can fall by a fifth.
• In-body and lens stabilisation: running both adds continuous draw, which is especially visible when handholding a long lens.
• Accessories: a monitor, a wireless video transmitter or a USB-powered microphone all draw from the body, and runtime drops by the added load directly.
• Cell ageing: a pack a year or two old has already lost usable capacity, so discount the table according to its real condition.

On long-take bodies such as the FX3 and FX30, the power strategy differs from the A7 series and the camera keeps some headroom in reserve for recording. Our dedicated piece on video power covers the arrangements.

Turning the estimate into a workable shooting plan

1. Fix the longest single take of the day — say a 45-minute interview.
2. Read the lower bound for that format off the table, for example 90 minutes at 4K 60p.
3. Divide the lower bound by the take length and round down: 90 ÷ 45 = 2 takes per pack.
4. Allow 5–10 minutes between takes for the swap and build that into the budget.
5. Work back from the total number of takes to the packs you need, and add one as a buffer.

Planned this way, even a runtime twenty percent short of the estimate will not leave you dark on location. Because the YO TNP-FZ100 has a Type-C port on the body, you can top it up from a power bank during a break instead of waiting to get back to a dock charger — on a long exterior day that is more useful than carrying one more pack.

FAQ

Why does someone else get two hours from the same battery when I get one?

Confirm three things first: whether the format matches (frame rate, resolution, codec), whether the screen is used the same way (LCD or EVF, at what brightness), and whether the ambient temperature is comparable. Any one of those can shift runtime by thirty or forty percent. The other person may also be quoting the accumulated total of several clips recorded with power cycles in between, which is not the same as one continuous take.

With 20% showing, how much longer can I record?

Do not scale it proportionally. Bodies estimate third-party packs non-linearly, so 20% may collapse into a warning within minutes, or may last another twenty. The safe approach is to treat 15–20% as the point where you must wrap up, and not to count it in your plan.

Runtime drops sharply in the cold — is the battery failing?

Usually not. Low temperature thickens the electrolyte and slows lithium-ion transport, so usable capacity falls temporarily and largely recovers at room temperature. Our cold-weather notes describe the behaviour and what to do about it. Only if it is also short at room temperature is ageing worth considering.

For longer takes, a bigger battery or external power?

It depends on the shape of the work. Handheld and moving between positions, two or three TNP-FZ100 packs are more flexible; for fixed cameras, interviews and livestreams that run for hours, external power with a dummy battery is simpler and avoids stopping mid-take. More specification detail is in the FZ100 series overview.

Short answer: a TNP-FZ100 takes roughly 5–7 hours on an old 5V/1A charger, 3.5–5 hours on a 5V/2A phone charger, 4–6 hours from a power bank, and 2.5–3.5 hours on an 18W-or-better PD charger. These are ranges rather than fixed figures, because the same pack’s charging time shifts noticeably with input power, cable quality, starting charge and ambient temperature. Below we go through the three supply types, and note when you should expect to fall outside those ranges.

First, the variables: why one pack can differ by a factor of two

The NP-FZ100’s rated energy is 16.4Wh (2280mAh / 7.2V). In theory a 10W input would fill it in two hours, but charging is not a constant-power process: constant current first, constant voltage later, and the final 20% often takes a third of the total time. How much current the charger can supply and how much the battery management chip will accept — the lower of the two is what sets the speed.

Three factors are commonly overlooked. The cable: losses in a poor USB-C cable drop the voltage that actually reaches the pack, and the charging chip reduces current in response. Temperature: below 10°C or above 40°C, most battery management schemes deliberately cut current to protect the cells. And charging while in use: if the pack is simultaneously powering the camera, the charging current is shared, and the time stretches accordingly.

Realistic time ranges for the three supply types

The table assumes charging from near empty to full, an ambient temperature of 20–25°C, and the supplied or a competent cable. The figures reflect the normal behaviour of USB-C direct-charge packs; individual units vary by tens of minutes.

Phone chargers: the tier people underestimate

Many of us still have a five-year-old 5V/1A charger in a drawer. It will charge the pack, but it will eat most of a day. If you need the battery first thing in the morning, plugging in overnight is fine; if you discover an empty pack at three in the afternoon and you are shooting at seven, this tier will not save you.

5V/2A is the value sweet spot

The 5V/2A charger bundled with most phones already brings the time down to around four hours, and the gap to a PD charger is far smaller than the price gap. For anyone with one or two packs and an unhurried schedule, this tier is enough, and there is no need to buy extra gear for fast charging.

Multi-port chargers share the power

Charge two packs and a phone at once from a three-way station and the total output is divided, each pack gets less current, and the times stretch proportionally. If you want speed, plug in separately; if you want to save sockets, accept slower charging. You cannot have both.

Power banks: portable, but count the conversion losses

A power bank is rated at 3.7V cell capacity. Getting that to 5V and then into the battery involves a boost conversion, and usable energy is typically only sixty to seventy percent of the nominal figure. From a 10,000mAh bank, two to three full charges of a 16.4Wh pack is a realistic expectation; do not divide the numbers and assume four.

Cold weather makes this worse. Below freezing the bank’s own output falls and the pack restricts charging current, so both sides are discounted at once and a four-hour charge can become six or more. Our notes on battery behaviour at low temperature have the detail, and are worth reading before a winter shoot.

PD chargers: fastest, but do not expect the full rating

The advantage of PD is that after negotiation it can supply a higher voltage, which reduces line losses and lets more power through. But a charger rated at 65W does not mean the battery will draw 65W — the charging chip on the battery side has a ceiling, and anything above it simply goes unused. In practice the gap between a 65W and a 30W charger on this pack is smaller than the numbers suggest.

The most practical way to find out how fast your combination really runs is to watch the indicator rhythm on the pack or the charging prompt on the camera, then time one charge from empty to full. One measurement beats any datasheet.

Planning top-ups when you rotate several packs

1. Back at the hotel, put the empty pack on the PD charger first — do not wait until after your shower to remember.
2. Charge the second on the 5V/2A charger at the same time, avoiding a multi-port split that would slow both.
3. Leave the third for tomorrow and take it to about 80%; storing at full charge long term is unkind to cycle life.
4. Check the power bank’s level before you leave, and in cold weather carry packs in an inside pocket rather than the outer pocket of the camera bag.
5. On multi-day shoots, a dual-slot charging case handles two packs overnight in one go.

The point of this routine is not the shortest possible time but making “there is always one pack at full charge” a habit. No charging speed rescues the evening you forgot. For more on matching bodies and batteries, see the TNP-FZ100 section.

FAQ

Why is my TNP-FZ100 still not full after six hours?

Look at the charger first. An old 5V/1A unit takes five to seven hours by nature, which is normal. If you are already on a 2A-or-better supply and it is still slow, check whether the cable supports higher current, whether the plug is fully seated, and whether the ambient temperature is unusually low or high.

Can I use a phone fast charger without damaging the battery?

Yes. USB-C charging negotiates voltage and current first, and the pack only accepts the tiers it can handle, so a powerful charger cannot force current into it. The precondition is that the charger and cable are legitimate products; poor accessories are the real risk.

Does unplugging halfway through harm the battery?

No. Lithium cells have no memory effect, and partial charging is normal use. If anything, routinely running the pack to auto-shutdown before recharging is worse for cycle life.

Does charging while shooting make it slower?

Yes. The pack keeps discharging while the camera records, the charging current is shared, and the time stretches noticeably, with both the body and the pack getting warmer. For long takes it is better to keep a charged pack in rotation than to push on with a cable; the limits are set out in our FZ100 battery section.

Short answer: the quickest way to tell them apart is the connector — a genuine NP-FZ100 has no charging port and must go on a dock charger; a YO TNP-FZ100 has a Type-C port on the front face; and a counterfeit “original” usually gives itself away through rough mould seams, soft marking fonts, the colour of the contact plating and the weight of the whole pack. This article only covers what you can see in your hand or under a lamp; it does not involve disassembly or internal measurement.

One caveat first: visual inspection only screens out crude fakes. A good replica can look very close, and in the end the sales channel and the price have to carry the judgement. The value of the checks below is that they let you rule out the obvious suspects quickly, without any special equipment.

First glance: is there a Type-C port?

This is the fastest step. Sony’s NP-FZ100 has five metal contacts on the base and locating slots on both sides, and no charging connector of any kind; charging requires a dock such as the BC-QZ1. So:

• A small USB-C port on the front or side marked 5V input means a third-party direct-charge pack, of which the TNP-FZ100 is the best-known example. That is a legitimate design, not a sign of a fake.
• A Sony logo together with a Type-C port is close to conclusive. Sony has never released an FZ100 with a direct-charge port.

The check works because counterfeiters routinely take an off-the-shelf third-party shell and print a Sony logo on it, or work the other way round. The presence or absence of a port is the hardest physical feature to fudge.

Mould seams and shell finish

Hold the pack up to a side light and look at the joint between the upper and lower shells. On a genuine pack the seam is fine and straight, with no step you can feel as you run a finger along it; the matte finish is even, the corner radii are smooth, and there is no flash or burr.

Fakes give themselves away here more than anywhere else: the seam is wide and misaligned, a fingernail catches in it, the shell reflects unevenly with flow lines or sink marks visible at some angles, and there are fine burrs at the edges, especially around the latch and the contact opening. It is a difference in tooling precision, and cutting cost makes it hard to hide.

A legitimate third-party product such as the TNP-FZ100 usually sits between the two — not as rough as a fake, but not required to match the original’s surface treatment either. Judge it as a third-party pack, not against the original’s standard.

Weight and feel

The genuine NP-FZ100 has a certain heft, and nothing rattles when you shake it — the cell is cushioned and located inside the shell. Fakes usually err one of two ways: noticeably light, because the cell is smaller and there is less filler, or a faint rattle when shaken, because the internal retention is inadequate.

Do not judge on grams alone: shell thickness varies between batches and without a precise scale the comparison is unreliable. What works better is a relative comparison — with a known genuine pack in one hand and the suspect in the other, a clear difference is worth investigating.

Markings and labels: font, depth, completeness

The most useful line in that table is capacity: the genuine NP-FZ100 is 2280mAh, so anything claiming 3000mAh or 3200mAh while wearing a Sony mark is almost certainly not original. Inflated capacity is the fake’s favourite selling point and also its easiest tell.

Contacts: count, arrangement and plating

The NP-FZ100 base has five contacts plus locating structures on both sides. Look at three things:

1. Count and position. On a genuine pack the spacing, width and position relative to the slots are all regular, and the five contacts are the same size. Fakes sometimes sit slightly off, and the pack feels tight or loose going into the bay.
2. Plating colour. Genuine contacts are an even pale gold with a soft reflection. Fakes often use cheap plating that is either too yellow and bright or dull and dark, and shows scratches and oxidation after a few insertions.
3. The plastic around the contacts. Genuine packs usually have a reinforced structure here with clean edges; fakes show moulding flash, and the contacts may sit slightly recessed or proud of the surface.

Contacts directly affect contact resistance. A poorly plated pack eventually produces the “shows charge, dies on record” behaviour, which is not a capacity problem but a contact problem — clean the contacts and the body’s spring pins before assuming anything else.

Which “authentication tricks” do not actually work

• Checking an anti-counterfeit code: plenty of third-party packs carry one, fakes can print one too, and the page it resolves to is usually their own. It proves very little.
• Judging by the box: packaging is the easiest part to copy, and well-printed fake boxes are not rare.
• Seeing whether the camera recognises it: most fakes now pass basic recognition. A percentage on screen does not make a pack genuine.
• Judging by price: absurdly cheap is of course suspicious, but good replicas sell close to the genuine price, which is precisely what lowers your guard.

What actually holds up is the combination: a legitimate channel, all five visual checks passed, and a price inside a sensible range. If any one is missing, stay sceptical. For compatibility notes and the pitfalls to avoid when buying, the TNP-FZ100 category page has a more systematic treatment.

FAQ

Will the camera warn that a third-party battery is not genuine?

Most bodies do not raise a warning, but they may not show the remaining shot count, or the percentage may jump. That is normal imperfect protocol compatibility and does not affect use. A few bodies tighten the rules after a firmware update; check your camera’s manual.

Can a battery with a Type-C port go on a plane?

Yes, under the usual lithium battery rules — carried in the cabin, and under 100Wh per pack. The NP-FZ100 family is 16.4Wh, far below the limit, and a direct-charge pack needs no special explanation at security. The detailed rules are in this guide.

Will a fake damage the camera?

With the right voltage it usually will not damage the body immediately, but the risk sits in the cell quality and the protection circuit. Poor cells may lack overcharge and over-discharge protection, and the odds of swelling, leakage and abnormal heat are clearly higher. If a pack becomes unusually hot or bulges, stop using it at once and do not leave it in the camera. For the wider picture on original versus third party, see the FZ100 series overview.

How do I confirm the pack in my hand is genuine?

Work through the order above: check for a Type-C port first (a port plus a Sony mark is effectively conclusive), then the mould seam and marking sharpness, then the contact plating, and finally compare weight and feel. If two or more checks are doubtful, do not use the pack for important work.

Short answer: the TNP-FZ100 records normally in an A7 IV or an FX3, but “charging while shooting” will not rescue a long take — once the pack is in the bay its own Type-C port is completely covered, so any top-up runs through the body’s USB-C input, and whether that holds depends on the body and the supply wattage, not on the battery. What really caps recording time is body heat, not capacity. For two or three hours or more of continuous recording, neither swapping packs nor charging while shooting is a good trade; external power is the steadier answer. Below we separate the real limits of the three routes.

First, one thing to clear up: the port on the battery is unusable in-camera

The direct-charge port on the TNP-FZ100 sits on the side of the pack itself. Once the battery is seated in the bay, the wall covers it completely and there is no room to route a cable. So in practice “charging while shooting with a TNP-FZ100” has exactly one form: the pack powers the body as usual, while a cable runs from the camera’s USB-C port to a power bank or a PD supply.

That route only works if the body accepts USB power. The A7 IV, A7S III and FX3 all take PD over USB-C, and with a suitable supply the camera draws from the external source first, so the pack’s discharge slows markedly or stops altogether. Older bodies support USB charging but not USB power — with a cable attached they keep drawing from the battery, only more slowly. Check your camera’s manual on this point.

Three supply routes, and roughly how long each lasts

The table gives orders of magnitude for 4K at a normal bit rate, around 22°C ambient, a single camera and continuous recording. Actual time depends heavily on bit rate, frame rate, screen brightness and whether a fan is running.

The third route replaces the real pack with a dummy of the same shape, wired to an external supply or a USB power module. It removes capacity from the equation entirely, which suits fixed-position interviews, livestreams and conference recording. For the wiring details, see our dummy battery power guide.

The three real limits of charging while shooting

Limit one: is there enough power?

A recording body draws in the 5–10W range, and more at high bit rates, with stabilisation on and the screen bright. Feed it from an ordinary 5V/2A power bank and the input may only just match consumption or fall slightly short, so the pack keeps draining — you have moved from one hour to two, not to unlimited. A PD supply of 18W or more is what gives the charge a chance to actually hold.

Limit two: heat adds up

Charging produces heat and recording produces heat; do both at once and the interior warms faster than with either task alone. The A7 IV is fairly sensitive to temperature during long 4K takes, and recording while plugged in brings the overheat warning forward. The FX3 has an active fan and more headroom, but a blocked intake or a hot environment will still trigger protection.

Limit three: a cable changes how you shoot

Plugged in means the camera cannot move freely; handheld follow shots, gimbal work and quick repositioning all suffer. Many people conclude that carrying two more packs and rotating is preferable to living with a cable — which is the argument for a dual-slot case.

When to give up on charging while shooting

The test is simple. If a single take runs longer than the pack can supply and you cannot stop in between, do not count on charging while shooting — go to external power. Interviews, lecture capture, livestreams and multi-camera stage work all fall into that group.

Conversely, for documentary following, weddings and moving exterior work, the cable costs more than it gives. The right approach is three or four packs, all charged overnight in a dual-slot case, swapped between segments during the day. In that workflow the direct-charge port on the TNP-FZ100 earns its place: at lunch, any USB outlet will put half a charge back into the pack you have just pulled.

Video power on the FX3 and FX30 involves finer trade-offs. Our FX3 and FX30 video power guide compares the two bodies, including cooling design and recommended supply wattage.

A configuration that rarely goes wrong

1. Fixed main camera: dummy battery on a large external supply, with the pack as a buffer for power interruptions.
2. Moving work: TNP-FZ100 in the body, two spares in the bag, everything recharged at the end of the day.
3. Mixed situations: body USB-C on an 18W-plus PD bank, as an extender rather than a substitute for capacity.
4. Summer outdoors: keep the body out of direct sun, let it cool between takes, and never leave a plugged-in camera sealed in a bag.

What these have in common is that runtime is never bet on a single method. The battery buys mobility, the cable buys duration, and each covers its own stretch. More accessory combinations are listed in the TNP-FZ100 catalogue.

FAQ

Will the FX3 overheat recording 4K from a power bank?

It can, but it is more forgiving than a fanless body. The FX3 has active cooling and typically runs a long time at room temperature, provided the intake is not covered by a hand or a sticker. In direct summer sun, every body loses headroom.

Does charging while shooting cause swelling?

Not in normal use. Swelling is mostly tied to prolonged heat, failed overcharge protection or cell quality. Keeping the camera out of a sun-baked car and avoiding unknown chargers are the more effective precautions.

Will an ordinary power bank extend recording time on the A7 IV?

It will extend it, but by how much depends on the bank’s output. A 5V/2A output mostly just slows the decline; holding the level needs a PD fast-charge tier. Confirming that your bank supports PD output before you leave saves more weight than an extra battery.

Does swapping the battery mid-take lose the clip?

It ends the current clip. To change packs without stopping, you need external power to carry the camera, or a supply design that supports two batteries. That is why fixed-position work leans toward a dummy battery.