Below are the different power sources for you to consider:
For the personal (mini) fans, battery-powered as well as grid electricity-powered options are available. Your choice should be based on the type of usage. If you intend to use it in settings with an electric power source, opt for a plug-in model. But if you are going to use this fan in remote areas or as a stand-by during power-outages, buy the battery-operated fan. Keep in mind that there are two types of batteries: replaceable and rechargeable.
The first is the dry cell or "D" type of use-and-discard battery, while the second can be recharged and reused. Opt for a fan with rechargeable battery for cost-efficiency and convenience. They will prove to be cheaper in the long run, and they can be recharged in two ways -- by plugging them into a power source, or through a power bank.
Some manufacturers offer dual power source for personal fans - battery and plug-in, so that you can operate it anywhere you want. They become excellent secondary fans. If you are sitting in a far corner of a room where the air-throw of the primary fan is insufficient, you can use your personal fan on battery mode. And if you are at your work-desk, plug it in the socket and use it.
For table, floor, and wall-mounted fans, 110V to 240V domestic alternate current (AC) power supply is the standard specification. They are not available with the battery-power option, as they are not designed for portability. Remember to place or install these fans near the power plug -- nearer the better. This will shorten the length of the electric cord, hence minimizing any risk of it tangling or its accidental pulling off of the cable. Such minor oversights can lead to major electrical accidents.