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
- Open the lid after a shoot, seat both packs in the keyed slots, contacts down and pressed fully home.
- Connect a USB supply of 5V/2A or more, and confirm both slot lights come on red.
- Put the case on a desk or another ventilated surface — do not cover it and do not charge it inside a bag.
- Take the packs out when the lights go green, or simply close the lid and go: the case is the storage box.
- 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.