Depending on the battery type, a direct short using a wire can cause the wire to light up and poof like a fuse. Worse, enough current might cause to the battery itself to overheat and leak or explode.What’s the minimum AWG size for a wire connected to a 9 volt battery without resistor?
Shorting batteries isn't recommended. What is the purpose of doing this?What’s the minimum AWG size for a wire connected to a 9 volt battery without resistor?
Aha, so you have a light bulb! In that case the minimum wire size depends on 1) The current draw of the lightbulb, 2) The length of wires required, and 3) The acceptable loss of power in the wires. That is, long thin wires will cause a voltage drop at the lightbulb and it will be a little less bright. If you don't care, then you could use a much thinner wire than if you do care and don't want any visible dimming.Like this https://ibb.co/WkfYC37 with a PP3 alkaline battery.
I was going to go the other way and say just use whatever wire is handy and don't worry about it, since the wire is not likely to have an impact. In other words, you don't need to worry about the minimum gauge because that minimum is smaller than whatever you want to use.I am going to stick my foot into my mouth and respond with 44AWG wire.
Just try it and see if it works.
(You know, I don't need any responses to this crazy answer, please.)