SONY FZ100

Short answer: the right way to run four packs across two cameras is not to give each body two — it is to number all four, pair them permanently by camera position, and stagger the swaps so that at any moment only one pack is recharging in the case and another is ready to go. That way you never reach a point where both bodies are flat with nothing charged. What follows is a rota you can copy directly.

The scenario: two A7S III bodies, one as the main angle (wide, head-on) and one as the second angle (side or hands), four NP-FZ100-class packs — two OEM and two third-party units such as the TNP-FZ100. Audio is recorded separately, with each take running 40–50 minutes and a 15-minute break between takes.

Step one: number and pair

Label the packs A1, A2, B1 and B2, with the sticker on the back away from the contacts and the heat path. Group A belongs to the main camera, group B to the second camera; they do not cross over or mix.

The reason for fixed pairing is that two packs used in the same body gradually converge in how they discharge, so your sense of how long a given pack will last gets sharper over time. Random allocation each day means relearning that every time. Constant mixing also levels out the wear across all four, which removes the buffer of always having one pack in better condition.

If the four are a mix of OEM and third-party, pair by capacity and condition rather than by brand. Two packs in similar shape in the same group make the swap rhythm predictable.

Step two: work out usable time per pack

Recording format	Whole-camera draw	Runtime per pack	At 40 minutes a take
4K 24p 10-bit	8–9W	About 100–120 minutes	2 takes, margin is tight
4K 60p 10-bit	9–10W	About 85–100 minutes	2 takes, comfortable
4K 120p 10-bit	11–12W	About 70–85 minutes	1 take, swap before the second

The figures are ranges derived from a power model, not measurements from a particular body. Temperature, screen brightness and whether stabilization is on all shift them, and a twenty percent deviation is common. Plan around the lower end of each range rather than the upper — the margin you leave is your room for error.

At 4K 60p and the 85-minute lower bound, one pack covers two 40-minute takes with something to spare. That means a morning of four takes needs only one swap per camera. That is the most comfortable rhythm available: fewer swaps, fewer interruptions.

Step three: stagger the swaps

This is the most important rule in the whole plan. If both cameras swap at the same moment, you get a window where both are stopped — precisely the situation you least want, especially when the two angles have to be matched, since realigning timecode after an interruption is a chore.

The method: swap camera A after take two, and camera B after take three. That way, whenever one body is swapping, the other is still recording, and only one camera goes down at a time. The pack that comes out goes straight into a DR-FZ100 slot to recharge, with the second slot reserved for the pack due to come out next.

A schedule you can copy

Time	Camera A (main)	Camera B (second)	Case status
Take 1, 09:00	A1 recording	B1 recording	Empty
Break, 09:40	A1 continues	B1 continues	Empty
Take 2, 09:55	A1 recording (margin tight)	B1 recording	Empty
Break, 10:35	Swap to A2, A1 on charge	B1 continues	A1 charging
Take 3, 10:50	A2 recording	B1 recording (margin tight)	A1 charging
Break, 11:30	A2 continues	Swap to B2, B1 on charge	A1 full, B1 charging
Take 4, 11:45	A2 recording	B2 recording	B1 charging

What matters in this table is not the clock times but the constraint behind them: only one pack charges at any moment. That guarantees the case always has a free slot ready to receive a pack that has just come out, and that you always know exactly how long the other pack has been on charge and roughly where it stands.

Step four: the recharge rhythm

Breaks are usually only ten to fifteen minutes. Taking a pack from low to fifty or sixty percent in that window is realistic; reaching full is not. So do not expect a break to finish a pack — the right expectation is partial top-up between takes, full charge at lunch or after wrap.

The lunch hour is the most effective window. One pack will very likely reach close to full in that time; two depends on the case’s total output, and if the slots share power, charging both is considerably slower than charging one. That is a practical point: at lunch, charging a single pack is often a better use of the hour than loading both.

If your packs are TNP-FZ100 units with a built-in USB-C port, there is a further option: a pack that comes out need not go into the case at all — plug it into a power bank and leave the case free for the other one. You have effectively gained a third charging position. On long location days this combination is very practical, and the FX3 power article covers the underlying approach.

Details that catch people out

• Never swap mid-take. A pack reading 15% can hit the warning within minutes. Put swaps in the breaks and do not gamble.
• Confirm the pack is seated before you walk away. A pack that is not latched may still light the indicator while not actually charging, and you only find out when you fit it and it is empty.
• Let a hot pack cool first. After continuous recording the pack surface is warm, and going straight into a closed case stacks the heat. Give it five minutes, or charge with the lid open.
• Log how each pack performs. Note on your phone that A1 lasted to the end of take two with one bar left; after a few takes your estimates correct themselves.

The value of a rota is that it absorbs uncertainty in advance. At the scale of four packs, two bodies and four takes, getting numbering and staggering right means almost no on-the-spot decisions. More detail is in the DR-FZ100 category, and judging pack condition is covered in the direct-charge battery category.

FAQ

Are four packs enough for a full day of two-camera work?

At four takes a day of forty minutes each in 4K 60p, usually yes, but without much spare. With more takes, longer ones, or 4K 120p, go to six packs or add external power to the fixed camera. The test is whether you can hold the state of two packs in use, one charging and one full at the start of every take — if you can, you have enough; if not, add packs.

Can the two cameras share packs?

Physically yes, but it is better not to swap them mid-shoot: it breaks your runtime expectations and levels out the wear curves. Swap only in an emergency, then update the numbering notes afterwards.

Can the case sit next to the cameras?

Yes, with two cautions: do not put it on the floor where it can be kicked, and do not press it against equipment that runs hot. A partly open lid helps heat escape but lets dust in, so on a dusty set keep it closed and top up back at the hotel.

Why stagger the swaps rather than doing both at once?

Swapping both saves you a few movements and costs you the risk of both cameras being down together. On a two-camera shoot the angles usually complement each other, so a simultaneous interruption means that stretch exists on neither card. Staggering costs two extra minutes and guarantees at least one camera is always recording, which is the better trade.

Short answer: the DR-FZ100 is a dual-slot charging case, so the slot count is the storage count — two NP-FZ100 packs at most, and a third will not go in. A camera body will not fit at all: an A7 series body with a pack inside is far larger than the interior, so this is not a matter of trying harder but of different orders of size. As for small items such as cables and memory cards, whether they fit depends on the internal layout of the particular unit, and the method at the end of this article lets you check that yourself.

A note on approach first: this article deliberately avoids figures such as interior length, width and height in millimeters, or the weight of an empty case to the gram. Those numbers should come from the unit in your hand and its documentation, and they can differ between batches. What can be given is the structural logic, comparable orders of size, and a two-minute procedure you can run yourself.

Why two packs and not three

The DR-FZ100 was designed around charging two packs at once, so the slots, contacts, latches and indicator lights all come in pairs. Each slot has a defined seating structure and a pack must latch home to count as seated. A third pack has no matching position and would simply sit on top — which means it will not charge and will press on the contacts and shell when the lid closes.

Some people reason that they will not seat it, just lay it in the lid. That achieves nothing: the lid only presses down properly when both packs are latched in their slots, and a loose pack shifts in transit and knocks against the latches and contacts. Half the value of the case is that you drop packs in and they charge, and close the lid and they travel.

So the storage ceiling is two. If your normal pattern is four packs in rotation, the right arrangement is two in the case and two in use, not one case holding four. The DR-FZ100 category has a two-camera article covering how to schedule four packs.

Why a camera body cannot go in

This does not need dismantling to settle; comparing dimensions is enough. Take the A7 series: the body alone, without a lens but with pack and card, is roughly 130mm wide, 96mm tall and 75mm deep, with bodies such as the A7S III a little thicker. The interior of a dual-slot case, by contrast, is designed around two packs of about 38.7mm width and 22.8mm thickness side by side, so its overall length and depth are both under a hundred millimeters.

Item	Order of size	Against the interior	Verdict
One NP-FZ100 pack	About 38.7 × 22.8 × 51.5mm	Matches one slot exactly	Yes, two of them
Two packs side by side	About 78 × 22.8 × 51.5mm	Matches two slots	Yes, this is the designed capacity
A7 series body, pack installed	Around 130 × 96 × 75mm	A single dimension already exceeds the interior	No
Body plus a small prime lens	Tens of millimeters deeper again	The gap widens further	No

The conclusion is clear: any idea of storing a camera body in the charging case is a non-starter. It is not a design trade-off but a difference in what the product is for — the case deals with how packs charge and travel, not with how a body is carried. Carrying a body means a camera bag or an insert.

A third pack, memory cards, cables

A third pack

No, for the reasons above. If you genuinely need to carry three or more packs in one container, choose a multi-slot charger or a separate battery case rather than forcing a dual-slot unit.

Memory cards

It depends on the unit. Some leave a small pocket or mesh sleeve on one side that holds one or two SD cards; others are pure slots with no spare volume. The way to tell: load both packs and see whether the remaining gap takes a hard card case — usually it will not, and a bare card will slide into the gap beside a slot.

It is better not to put bare cards in a battery case at all. Card contacts are more delicate than battery contacts, mixing them risks scratches, and pulling a card out tends to bring a pack with it.

Charging cables

Most dual-slot cases expect the cable to stay outside; there is no room to wind one inside. Forcing it in presses on the lid and loosens the latch over time, so a cable tie is the better answer.

The two-minute self-check

1. Seat both packs and confirm they latch home with the indicator lights behaving normally.
2. Close the lid and press gently on it, feeling for springiness or a localised bulge. A bulge means it is already full — add nothing more.
3. Pick the case up and shake it lightly, listening for anything shifting. A rattle means something is not secured.
4. Open it and look for clear gaps around the interior, and check whether those gaps run through to the slot area. Small items in a through-gap will slide into the contacts.
5. If you intend to add a card or an adapter, put it in, close the lid, shake again and repeat steps 2 and 3.

This turns whether something fits from a guess into a test. Any arrangement that needs force to close should not be used long term.

A more practical arrangement

If you regularly carry four packs or more, split the two jobs: one dual-slot case for charging, a separate container for carrying. The case then only has to charge, not carry everything, and it lasts longer — repeated overloading and lid pressure is the most common cause of a distorted body.

The other direction is to depend on the case less. Packs with a built-in USB-C port, such as the TNP-FZ100, need only a cable and a power bank on the road, and each pack can live in any compartment rather than being collected in one place. Once you have several packs, that approach usually wins on volume. The weight and volume comparison between the two routes is in the direct-charge battery category.

One more point that gets overlooked: the rules for flying with lithium batteries are built around carrying them with you. How you pack does not change compliance, but spreading packs across several bags makes counting them at security slower. Kept together in one case, you get through faster. The rules are in this article.

FAQ

Will the DR-FZ100 take third-party packs?

Usually yes. Any pack built to the NP-FZ100 outline varies very little in size and latches in normally. A few third-party packs with a thick protective shell or extra structure can be tight; do not force them, and check first whether it is a shell tolerance issue. The compatibility list is collected in the FZ100 series overview.

Can I put the loaded case straight into a camera bag?

Yes, but not at the bottom under heavy items. The shell is rigid with limited crush resistance, and sustained pressure loosens the latch and distorts the contacts. The top layer or a side pocket is better.

Does an empty case take up much room?

More than two bare packs — that is what the rigid shell buys you. If you only carry two packs and have no need to charge on the go, bare packs are lighter. Whether to bring the case comes down to protection and charging versus volume.

Can packs and a body share one bag?

Yes, but the packs are better off in their own soft pouch or hard case. Loose packs mixed with a body and lenses pick up metal debris on the contacts and get their shells scratched by mounts and screws. That applies equally to OEM and third-party packs.

Short answer: the DR-FZ100 is a dual-slot charging case that charges two NP-FZ100 packs at the same time and becomes a storage box once the lid is shut. Seat the packs contact-side down, connect power, and the indicator lights show charging status; two packs together typically take 3 to 5 hours. It is not a battery and plays no part in powering the camera — its value is folding charging and storage into one action. What follows covers the lights, the timings and temperature control, then a routine you can use every day.

What it actually is: three things to keep apart

People regularly confuse the DR-FZ100 with a battery. The short version: the NP-FZ100 is the pack that goes in the camera; the TNP-FZ100 is a replacement pack with its own USB-C port that can be charged on its own; the DR-FZ100 is the case that charges them. The three work together rather than replacing one another.

Inside are two independent slots. You can load one or charge both. The slots are molded to the NP-FZ100 outline with keying that prevents fitting a pack the wrong way round — a reversed pack will not let the lid close. With the lid shut, the case is a rigid storage box: packs cannot roll around in your bag, and the contacts cannot touch keys or screwdrivers.

Reading the indicator lights

Light logic can vary slightly between production batches, but the common states are broadly the same. The table below gives the usual meanings; the sheet that ships with your unit takes precedence. If you have lost it, the most reliable approach is a controlled test: put a discharged pack in and watch the color change from start to finish, then note it down.

Indicator	Usual meaning	What to do
Red, steady	Charging	Normal, just wait
Green, steady	That slot is full	Remove the pack, or leave it as storage
No light	Pack not detected, or no power	Check the pack is seated fully and power is connected
Flashing	Fault, usually thermal protection or poor contact	Disconnect, remove the pack, let it cool, then retry

The two slots work independently: one turning green while the other stays red is normal, and simply reflects different starting charge levels. If both go in together and one finishes well before the other, the difference usually comes from capacity or from how worn the two packs are.

How long two packs take

If the case charges in parallel, the two slots share the input power and each pack charges more slowly than it would alone. With a typical 5V supply, one pack takes about 2.5 to 4 hours and two together about 3 to 5 hours, depending on the supply’s output current and how much charge is left in each pack.

That range is worth remembering because it determines how you plan. Start two packs at ten in the evening and they are done a little after one; plug in at midnight with a seven o’clock departure and you still have enough time. What really causes trouble is powering the case from a computer’s USB port — those typically deliver only 5V/0.5A, which stretches the job past eight hours.

To shorten it, the direct move is a USB supply with more output current, not a different cable. Cables only affect losses; the supply sets the ceiling.

Temperature: three things not to do

Some warmth while charging is normal — even a lithium pack converts around ninety percent of the energy it takes in, and the rest becomes heat. The case is compact, so heat concentrates, which makes where you place it more important than most people assume.

Do not charge inside bedding, a sofa or a camera bag

These places trap heat, the internal temperature climbs, and once it hits the threshold charging slows or stops. On the surface it looks like a pack that charged all night without filling up; in reality thermal protection kept stepping in. On a desk in open air the problem disappears.

Do not charge in a sun-baked car

A closed cabin in summer can exceed sixty degrees, and no lithium battery should be charged in that. At best it throttles, at worst it trips protection. If you must top up in the car, run the air conditioning or at least open a window.

Do not drop it straight into a sealed bag when full

A freshly charged pack and the case both carry residual heat, and a sealed pouch gives it nowhere to go. Waiting ten minutes before packing up is a habit that costs almost nothing.

Cold is the opposite problem. Below freezing the pack’s internal resistance rises, the case limits its charging current, and it looks as though the pack will not take a charge. Let it sit at room temperature for half an hour first; that is safer than forcing it, and the cold-weather test notes have the supporting detail.

The daily routine

1. Open the lid after a shoot, seat both packs in the keyed slots, contacts down and pressed fully home.
2. Connect a USB supply of 5V/2A or more, and confirm both slot lights come on red.
3. Put the case on a desk or another ventilated surface — do not cover it and do not charge it inside a bag.
4. Take the packs out when the lights go green, or simply close the lid and go: the case is the storage box.
5. For long-term storage, leave packs at around half charge and top them up every two or three months.

Step three is the one that matters. Most complaints about packs that will not fill, or charge slowly, trace back to a case left smothered inside a bag. The case is designed to be opened up on a hotel nightstand, not wedged into the corner of a suitcase.

How it divides work with a dock and direct charging

Each of the three charging methods has its place. A TNP-FZ100 with its own USB-C port suits topping up half a charge in the field, in a café, or anywhere without a case; a single dock suits light travel where only one pack needs charging; a dual-slot case suits the habit of emptying the day’s packs in one go every evening. For anyone with three packs or more, the case’s efficiency advantage is clearest, and the dual-slot charger section has the comparisons.

For choosing the packs themselves and which bodies take an NP-FZ100, see the Sony FZ100 battery section, which includes a body-to-battery chart.

FAQ

Can two packs of different capacity charge together?

Yes. The slots are managed independently and each decides when it is full. The larger pack simply turns green later, which is normal and does not affect safety.

Will leaving packs in after the green light overcharge them?

A properly built case switches to a maintenance state once it detects a full pack and does not keep pushing current in. Even so, sitting at full charge and warm for hours is not good for cycle life, so take them out when you can.

Can I use the case as a storage box on the road?

Yes — closed, it is a rigid box that keeps dust and knocks off the packs. Just do not put screws or coins inside, and do not let heavy items press on it in the bag for long periods.

Why does the indicator keep flashing?

Disconnect power, remove the pack and feel whether it is noticeably hot. Let it cool and try again; most cases recover. If it keeps flashing, check the contacts for dirt, wipe them gently with a dry cloth and retry. If it is still abnormal, stop charging it.