I originally thought that I could use any type of thin wire, but after some research, it seems that different voltages and milliamps require different size wire. Am I correct with this?

My question is, what type of wire is recommended to use with that type of battery?


  • 2
    \$\begingroup\$ mAh is capacity, not current. \$\endgroup\$ – Ignacio Vazquez-Abrams Dec 30 '17 at 16:06

The conductor thickness needs to be chosen relative to the current flow ie a higher current needs thicker conductors and as voltage increases the insulation tends to be thicker / better.

However, the voltage drop or losses also mean that a thicker conductor can be necessary.

You need to specify the maximum current to flow then as suitable size can be selected.

  • \$\begingroup\$ I assume assume the maximum current flowing would be 750 mA if that's what the battery is rated at. Am I correct with this? \$\endgroup\$ – Vbs Dec 31 '17 at 18:16
  • \$\begingroup\$ Read the first conment re mAh and A... \$\endgroup\$ – Solar Mike Dec 31 '17 at 20:48

Typically, you get wire size from an ampacity table. (Google "ampacity table").

There are two main things to consider. First what is the normal current? Wire must be sized adequately to carry the normal current without excessive voltage drop. Usually in short wires this is not a problem unless the discharge rate is very high. But you can look up the resistance of the wire (lots of charts online), per length, and calculate the resistance of your wire harness. Then multiply resistance by current to get voltage drop. Often, I choose to allow 0.05 to 0.1V of drop in the wire, but it depends on many details.

Second thing is fault current. What is the highest fault current that could possibly flow for an extended period? For example, if you have a 1A fuse inside the battery pack, it can pass 1A for an extended period. It would be a good idea to choose a wire that will not overheat with, say, 1.5A. Then, no matter what fault occurs on your load, at least the wire insulation will not turn black or start a fire.

If the battery does not incorporate a fuse or other over-current protection, you should use a different battery that does. Lithium ion battery packs should have a built-in protection circuit that limits charge and discharge current and voltage. This is widely known in industry, so there is a good chance that the pack you are considering does have a protection circuit built-in to it.

  • \$\begingroup\$ Yes, the project I'm doing will only require very short wires as I'm wiring something in a tight space of 2in x 2in square. Seems like 30 AWG wire wrap wire would work fine in these types of circumstances. That's a pretty common wire type as well, correct? \$\endgroup\$ – Vbs Dec 31 '17 at 18:15
  • \$\begingroup\$ There is absolutely no way to say what wire diameter is required unless you specify normal current and max fault current. In general, 30AWG is pretty thin wire. I would not normally use it for power. \$\endgroup\$ – mkeith Dec 31 '17 at 18:31
  • \$\begingroup\$ How would I find the normal current and max fault current? I am a complete beginner at electronics, so I apologize if my question seems trivial, but I honestly do not know how to find those values. \$\endgroup\$ – Vbs Jan 2 '18 at 0:15
  • \$\begingroup\$ Normal current is just how much current does your device use normally? If you don't know, then maybe there are some spec sheets or data sheets for the device? When I say maximum fault current, I mean the highest current that the battery will allow without its protection circuit triggering. That might be listed in the datasheet for the battery. If you have those datasheets, please edit your original question and add the links or whatever. \$\endgroup\$ – mkeith Jan 2 '18 at 1:49

Always quantity of size of wires varies according with your power rating of flow of electric current . For a larger flow of electric current need wire with a larger crossection area . But you can compare wires used to provide power for sockets at the sitting room its crossectional area are smaller than the at kitchen socket . So your correct about that because the crosectional area a varies according with the rating of flow of electric current


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