Do wire gauges add together for positive and negative wires?

[papasapien]

May be the dumbest question asked on here but I need to know. I've asked people before how a bike will come with 8 gauge wire and be able to push 100a consistently. And they were just like idk 8 gauge is good it's what my bike came with.
Any ways I'm building a battery and I want a beefy connector but they'll have them so they only fit a smaller size which wouldn't be able to even push as many amps as the connector is rated continuously. It would only make sense if some how there is some super magic god tier wire I can't find any where or is the positive and negative wires add up their total amps to give you the right higher number the connector would be rated for?
Am I right? Idk this was a hard question to google that's why I typed it here sorry. I've watched so many videos but I've never heard any one mention this so maybe I'm not right Im not sure. I always just over buffed on the wire and connector. But now I'm thinking I can make them smaller with the same results. Please let me know thanks. And if I'm wrong where can I find such wire.(for instance I know of a connector used in sur Ron ebikes which is rated for 200a continuously but only accept 8 awg wire(maybe 6awg maximum I think)

 

[Chalo]

The voltage drop and power loss (heating) in a wire is a function of the square of the current, the gauge of the wire, and the length of the wire. Many times I've pointed out that the circuit board traces and FET legs of our controllers are many times smaller than the recommended gauge. But, they are short, and they have appropriate heat sinking.

If you're worried about pushing too much current through a wire because the connector won't take a bigger gauge, then either the connector is being abused or you're needlessly worried.

Keep your cables as short as is practical, make good crimps, and watch for signs of heat. If you don't get signs of excess heat, then no problem.

https://www.powerstream.com/Wire_Size.htm

 

[papasapien]

If you're worried about pushing too much current through a wire because the connector won't take a bigger gauge, then either the connector is being abused or you're needlessly worried.

but lets say you want to use this connector

https://www.maxamps.com/qs10-anti-spark-male-female-connector-pair?gclid=Cj0KCQiA34OBBhCcARIsAG32uvPuVCSVa_OwnFtt4AQZc1AEFcrdl9JHitO6E9ziJJUTpaMOPWtSqb8aAu7MEALw_wcB

its rated for 400A, but only fits up to 4 gauge wire.
how can 4 gauge wire even do 400Amps in the first place?
or will the positive and negative wires both at 4 gauge installed into the connector come to a higher maximum ampere?

 

[markz]

Even 0000 gauge amapcity is rated for 200-260A for copper depending on temperature.
0 gauage is 125-170A.
4 awg is 75-95A

So what they probably mean by 400A is instantaneous and not continuous.
Its 10mm bullets, capable of 4awg wire termination handling 400A for ESC or instantenous battery discharge for a certain amount of time, not continuous.

1x Female = Battery side
1x Male = ESC and Charger side

 

[amberwolf]

or will the positive and negative wires both at 4 gauge installed into the connector come to a higher maximum ampere?

No, because they are in series. They'd ahve to be in parallel for that.

 

[papasapien]

[/quote]
No, because they are in series. They'd ahve to be in parallel for that.
[/quote]

oh i see that does make sense

 

[john61ct]

When you know the maximum current that your infrastructure needs to support

peak amps (seconds) being vastly higher then continuous (minutes)

And the distances involved

safety from overheating being one issue, minimising voltage drop a separate one

play with the Blue Sea Circuit Wizard to see some of the other variables involved

You arrive at your wire gauge requirement, square area cross section, rounded well up. Fuses should be rated well **below** the max wire rating for safety, many say at 80% - you are ensuring you never approach that rating.

Then, every other component - connectors, terminations, switches buss bars etc

should be rated **higher** than that wire gauge for safety.

You are not trying to "get near to" their ratings, you are trying to stay **far away** from them, Nothing wrong with a 40A current flowing through a 100A rated component.

Especially when using cheap stuff made in China, where ratings are always "optimistic" and often a joke

 

[john61ct]

Note that Circuit Wizard assumes you know, the positive wire and the negative return **round trip** is the distance to input.

So if source and load are 10' apart, you have a 20' distance to account for.

Do not eyeball or guess, get a cord and actually lay out the wiring path, always rounding up rather than down.

 

[papasapien]

thank you john, this makes sense now. much appreciated.
instead of finding a connector and then a wire to fit I should instead find the appropriate wire for my load and then find a correctly sized connector that can more than handle the amp load.
I will use all of your advice you listed

 

[fatty]

instead of finding a connector and then a wire to fit I should instead find the appropriate wire for my load and then find a correctly sized connector that can more than handle the amp load.

The existing connector sizes are probably fine, although the quality of wire and termination may not be.

Wire has resistance inversely proportional to cross-sectional area. As current flows through the wire, that resistance turns some into heat. Therefore, wire continuous current rating is constrained by insulation temperature.

The short answer is to use wire that fits your connectors and has continuous current rating at least as high as your controller or motor continuous current. You can find wire with higher current capacity at the same wire gauge (usually with higher-temperature insulation).
Transient peaks will be fine, and practical limitations on wire size (cost, weight, connector compatibility) will limit you to reasonable wire sizes anyway.

Secure and sealed terminations/connectors (preferably crimped and soldered) are far more important than one wire gauge difference over a few inches.