Start from the batteries, not the charger
A camera battery charger is chosen for the batteries it must serve, not for its own features alone. List the battery types it must charge, how many must be charged at once, and where it will be used, before looking at charger models, because those three facts determine which chargers can serve and which cannot. A charger that serves the wrong battery types, however well made, cannot serve the buyer.
A charger that serves one battery type well may not serve another, because battery types differ in voltage, connectors, and charging requirements. Name the battery types in the inquiry, so the seller can check them against the charger's specification, rather than assuming a charger that looks similar will serve.
How many batteries at once
A dual charger serves two batteries, a triple charger three, and a four-slot charger four, and the choice depends on workflow, not just on numbers. A single shooter with two batteries may need only a dual charger, because one battery charges while the other is in use, while a team with many batteries may need a triple or four-slot charger, so all are ready together.
More slots mean more batteries ready together, but each battery may charge more slowly, as the triple and four-slot model pages show: output current falls as more slots are filled. A team that needs many batteries ready together should plan for the slower per-battery rate, and should not assume full speed for all slots at once.
Universal chargers and their limits
A universal charger claims to serve several battery types, and its output range describes the voltages it covers. A universal claim should be checked against each battery type it must actually serve, because a voltage range alone does not guarantee fit or connector match, and a charger that covers a voltage but not a connector cannot charge that battery.
The universal model on this site lists its output range and its included adapters, and the inquiry is the place to confirm coverage for each battery type. A buyer who needs a universal charger for many types should list every type in the inquiry, so the confirmation covers all of them, not just one.
Travel chargers and input voltage
A travel charger is compact and covers a wide input voltage range, for use in different locations, and it suits a shooter who charges on the move. Check the input range against the locations where it will be used, because a charger with a narrow input range may not work in some locations, and a charger that works everywhere is worth more to a traveller than a larger charger that works in one place.
Weight matters for a travel charger, because it is carried with the camera gear, and a heavy charger adds to the load on every journey. The travel model on this site is the lightest charger in its category, and its weight reflects its purpose. A traveller should weigh the charger's weight against its capacity, as with any travel gear.
Input, output, and power together
Input describes how the charger is powered: USB-C, Micro, or AC mains, at a stated voltage and current. Output describes what the charger delivers to the battery: voltage and current, per slot where stated. Power describes the charger's total output, where stated. All three together describe a charger, and a charger with the right output but the wrong input cannot be powered.
Do not choose by a single figure, and do not assume a figure for a model that does not state one. Check the specification table against the batteries and the workflow, and confirm in the inquiry, naming the battery types and the number that must be charged at once.
Charging time and planning
Charging time describes how long a battery takes to refill, and it matters for planning, because a battery that needs hours to charge must be charged well before it is needed, not between takes. Some model pages state charging times, and those figures should be used for planning, while models that do not state a charging time should be asked about in the inquiry, not assumed.
A shooter who needs batteries ready for a shoot should plan charging the night before, or carry enough charged batteries for the shoot, rather than relying on fast charging during the shoot. A team should plan charging as part of its workflow, with enough chargers and slots for its batteries, rather than as an afterthought.
Safety and charger matching
Use a charger that matches the battery, and do not use a charger with the wrong voltage or current for a battery, because a mismatched charger can damage the battery or be a safety risk. Charge in a ventilated place, where a charging battery can be watched, and do not leave a charging battery unattended for long periods, especially overnight or in a hot place.
These are general terms, not a safety manual for a specific charger or battery: the charger's and the battery's own documentation should be followed where they differ. A buyer who needs safety documentation for a specific model should ask in the inquiry, and should not rely on general terms alone.
Before you order a charger
Name the model, the battery types it must serve, the quantity you have in mind, and the market you sell into, in the inquiry. Ask for the specification for the exact model, the minimum order quantity, the lead time with its meaning, the warranty terms, and the certificates that apply to your market, by name, with documents attached. Do not pay before these have been confirmed for the exact models in the order.
A charger is only as good as its match to the batteries it must serve, and the match is only as good as the confirmation. The checklist takes a few minutes, and it prevents a costly mistake. The charger guide explains the types in general terms, and the charger model pages give the per-model specifications.
A note on sources and confirmation
The model specifications and compatibility statements referred to in this article come from the company profile's official product pages, as presented on this site's model and category pages. Compatibility statements are the company profile's own statements, quoted with attribution, and they are not statements by the equipment makers, nor do they imply authorisation, endorsement, or original manufacture. A specification stated for one model is not carried to another model, and a figure stated for one model should not be assumed for any other.
Figures that are not stated on a model page — a price, a minimum order quantity, a lead time, a warranty period, or a certificate for a specific model and market — are confirmed per order in the inquiry, and this article does not invent them. A buyer who needs any of those should ask for it by name, for the exact model and the exact equipment variant it must serve, with documents attached where documents are what is needed, so the answer is specific rather than general.
Before ordering, name the model, the exact equipment variant it must serve, the quantity you have in mind, and the market you sell into, in the inquiry. Ask for the specification for the exact model, the minimum order quantity, the lead time with its meaning, the warranty terms, and the certificates that apply to your market, by name, with documents attached. Do not pay before these have been confirmed for the exact models in the order, because payment removes the leverage to resolve an unconfirmed item, and a confirmed order is the only basis for a safe purchase.