For four packs a day, two bays are enough for most people and four bays suit high-intensity or team work. The deciding factor is not the number of bays but whether the total charging time fits into the hours you are not shooting. With a clear six-to-eight-hour overnight window, two bays in two batches is fine. With only two or three hours before bed, or if you need to top up during the day, four bays earn their place. One caveat that catches people out: a multi-bay charger has a finite total output, so per-bay current usually drops when every slot is filled, and advertised fill times should be read with that in mind.
First, the Time Arithmetic
| Charging window | Bays to use | Why |
|---|---|---|
| A full night, 6–8 hours | Two is enough | Two batches, one swap before bed |
| 2–3 hours before bed | Four is safer | Load it once and avoid a midnight swap |
| Topping up during the day | Two bays plus portable power | Pair with a power bank or car adapter |
| Team with several bodies | Four bays, or two dual units | Two units spread the risk; one failure does not stop everything |
A pack rated around 2280mAh / 16.4Wh normally takes several hours on a routine-current charger, depending on the charger’s output and how much charge is left. Read the stated output figures rather than the marketing claim about fill time.
Two Bays: The Sensible Default
- Strengths: small, light, inexpensive, easy to travel with, and per-bay current usually stays reasonably healthy when loaded.
- Suits: two to four packs a day with a proper overnight window.
- How to run it: two packs before bed, swap to the other two in the morning — or charge the two you used during the day first, then swap at night.
- Care: multi-bay units run warmer when loaded. Keep them on a ventilated surface.
Four Bays: When They Are Worth It
- Weddings, commercial work and events where you burn four-plus packs and get back late.
- Studios and rental houses turning packs over daily.
- Teams sharing one charger, where bays are literally throughput.
- Anyone who wants charging to be a single before-bed action with no 2 a.m. swap.
Total output is the number that matters on a four-bay unit. Two four-bay chargers can behave very differently: a high-output model barely slows when full, while a low-output one can end up slower than a dual charger. Look for the per-bay output figure when all slots are occupied.
A Simple Routine for Four Packs a Day
- First thing after a shoot: take every used pack out and wipe the terminals. Sweat and dust raise the odds of poor contact.
- Set priority: the two packs you need first tomorrow go on the charger first.
- Load and check the lights: confirm every bay is actually charging — steady red is normal, and a flashing red is dealt with in reading the indicator lights.
- Pull packs once done: do not leave them sitting on a live charger overnight if you are not using them until the afternoon.
- Store properly: fit terminal covers, put packs in a case by number, and keep the rotation order obvious for the next morning; see terminal covers and storage cases.
Four Safety Rules for Multi-Bay Charging
- Charge on a hard, flat, ventilated surface. Not carpet, not a bed, not inside a camera bag.
- Leave space between bays. Do not stack chargers or cover them with anything.
- Packs at different states of health behave differently — a worn one runs hotter, so check for temperature differences between packs.
- If the charger shell is hot, smells or buzzes, cut power and stop using it.
How Many Packs Should You Own?
If you are charging four a day, you already own at least four. A good rule is what a day consumes plus one: if you get through three, carry four, so there is slack when something goes wrong. For weddings and travel, plan against how many batteries to carry when travelling and add a pack for the body you did not expect to use.
FAQ
Is a loaded four-bay much slower than a two-bay?
It depends on total output. A unit with limited output drops per-bay current noticeably when full, so charging four at once can take longer overall. Check the per-bay figure with all slots occupied.
Can I mix capacities in one charger?
Generally yes, since bays are managed independently. Do expect different finish times between a 2280mAh and a 2400mAh pack, so check each bay’s light separately.
Can I fly with a multi-bay charger?
The charger itself is normally unrestricted. The packs are the regulated part: under TSA and FAA rules, spares must travel in carry-on, never in checked bags, with terminals protected against short circuits. At roughly 16.4Wh these packs sit well under the 100Wh threshold, so no airline approval is needed, but confirm details with your carrier.
Is a model with a display worth it?
A display showing voltage, current or percentage helps if you need to track progress closely. Most people get everything they need from the indicator lights.
When you are buying packs and a charger together, the kit is the better arithmetic. 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, which puts the charger at roughly $5. The TNP-FZ100 at 2400mAh / roughly 17.3Wh runs about $24.70 with one charger and about $39.92 for two batteries and a charger. If you need four or more, or you are turning packs over in volume, go through wholesale enquiry, where orders over 100 units are quoted per batch.