Short answer: with four batteries and two bodies, the point is not carrying more — it is numbering, a fixed rotation order, and one consolidated charge each evening. Concretely: split the four into groups A and B, A for the main body and B for the second, number each 1 and 2 within its group, swap strictly 1 to 2 through the day, and put the two spent batteries into the DR-FW50 together at night with the lid closed. The value of the routine is not saved power but the fact that you always know which battery is in hand, how much it has left, and where the next one is.
The plan below assumes a common pairing such as an A6400 with an A6000, or an A6400 with a ZV-E10. Both bodies use the NP-FW50 and the batteries are fully interchangeable, which is one reason this system suits two-body work.
Why two bodies need a rotation more than one
With a single body you carry one battery, and when it dies you change it. Simple. With two, the picture becomes two batteries in use, two in the bag, and two possibly in the case. Any moment of “I’ll just set this down” leaves you staring at four near-identical batteries half an hour later.
The FW50 shell has no charge display; you only learn the level by putting it in a body. That makes one misjudgment cost a lens change, a battery door, a swap and a remount — and at an event those thirty seconds can be the shot you miss.
A rotation turns improvisation into a fixed sequence. You do not have to remember anything; you just follow the rule.
Step one: number and group
- Label all four. With a fine marker or label tape, write A1, A2, B1 and B2 on the back. Do not write on the contact face or anywhere that blocks the latch.
- A for the main body, B for the second. The groups do not cross. The main body is usually the busier one, so give group A the two batteries in better condition.
- Record the starting state. One line in a phone note: A1 new, A2 new, B1 genuine but old, B2 genuine but old. Three months later you will know which to retire first.
- If one of the four is a TNP-FW50, put it in a group rather than setting it aside. Its USB-C port makes it the natural pick for the midday top-up slot; body compatibility is on the TNP-FW50 category page.
Labels exist to remove decisions. Before you leave you do not think about which two to take: A1 and A2 go in the bag, B1 and B2 are the spares. That is the whole system.
A day’s rotation schedule
| Period | Main body (group A) | Second body (group B) | Case status |
|---|---|---|---|
| Before leaving | A1 full | B1 full | A2 and B2 full, standing by |
| Morning | A1 in use | B1 in use | Bays empty |
| Lunch break | A1 swapped out and cased | B1, depending on remaining charge | A2 goes into the body |
| Afternoon | A2 in use | B2 takes over as needed | A1 charging |
| Wrap | All swapped out | All swapped out | Two charging, two waiting |
The pivot of this table is the lunchtime swap of A1. Most people shoot a battery until the camera shuts down, but with two bodies, deliberately replacing a half-full A1 at lunch avoids a scramble at the start of the afternoon. A1 goes straight into the case and is back by dinner.
The second body usually draws less, so group B needs one change a day. If the second body is running long recordings, treat it on the same rhythm as the main one.
Charging back at the hotel
The DR-FW50 takes two batteries at a time, so four means two rounds. A sensible split is the two that ran dry today first, the other two second. Two hours or so per round is typical, which is enough to finish both before bed. For the specifics of using the case, see the DR-FW50 category page.
If time is short, run a parallel top-up through the YO TNP-FW50’s USB-C port: one battery in the case, one on an adapter, and the two cables do not compete. That is the most practical value of a direct-charge battery on a trip — not replacing the case, but opening a second lane when the case is full.
Charge on a ventilated table, not on a bed, a carpet or inside a suitcase. The lid belongs closed for storage; while charging, leave it open to shed heat and close it once the lights go out.
Three common ways this falls apart. Avoid them in advance.
- Forgetting which battery is uncharged. Four identical shells defeat memory. The rule is: the moment a battery leaves the body, it goes into the case, never back into the bag.
- Charging only two and calling it a night. The second round is the one that gets skipped. Set a phone reminder, or leave the case by the door so you pass it on the way out.
- Bringing too few cables. The case is powered over USB-C, and one spare cable solves more problems than one spare battery.
One further detail: do not bury all the batteries at the bottom of your carry-on. Pressure at security and while lifting bags in and out of vehicles is the main source of deformed shells.
FAQ
Are four batteries enough for two bodies over a full day?
For most event work, yes. At 300-400 frames per battery, four cover roughly eight hundred to fifteen hundred shots. For long 4K recording, plan on three per body instead.
Can two bodies share one set of batteries?
Yes. The A6000, A6300, A6400, A5100 and ZV-E10 all use the NP-FW50 and the batteries are fully interchangeable — which is exactly why this system suits two-body shooting.
Can the DR-FW50 charge two batteries at once?
Yes. The two bays are controlled independently and can charge two NP-FW50 series batteries at once, with each bay stopping when its battery is full. With the lid closed it doubles as a storage case.
Can an A6600 join this rotation?
Not directly. The A6600 uses the NP-FZ100, so neither battery nor case is shared and it needs its own kit. See the FZ100 category page for details.