Wire Gauge and plug Size

[Mides]

I'm looking at upgrading my ESC combo to 2 x Tekin FXRs.

What gauge wire do most people use in their crawlers and does it depend on motors and battery being used? Would I get the wires overheating if I was to use 16 gauge wire with a 3s battery and two 35-55T motors?

Also, would Micro Deans work for the same set-up from battery to ESCs? Or will I be melting plugs?

From my understanding, there is far less amp draw from a crawler than from a touring car, monster truck, etc. Am I correct, meaning that we can use smaller wires and plugs?

[EddieO]

16 is ok, though I would use 14 if you could. While the micro deans can work, I don't recommend them. Just use a normal deans and call it a day. Plug failure with lipo can lead to your truck turning into a molten fireball...

Later EddieO

[ittybitty]

Agreed...I prefer 3.5mm bullet connectors for the esc to motor connections...makes it easy to reverse polarity if you needed to for some reason...for instance if you have more than one rig. I do use 16 gauge too.

[Mides]

Thanks for the help guys. So far i will go 16 gauge, but with normal Dean's plugs. Too easy.

[JohnRobHolmes]

I use 13ga on everything, but I tend to be a power hog. Everything runs more efficient with bigger wire.

Some guys go down pretty tiny on comp rigs. 16 and 18ga wire is pretty common. They are leaving power on the table though, plenty of voltage drop across those wires when a rig gets bound down. With 18ga at 30 amps there is .5v drop in a system with two total feet of wire (6 inch leads on motor and battery). With 13ga there is 0.15v drop. I will take my 3 times increase of wire efficiency please!


Smaller wire also causes higher ripple voltage, so it beats on the controller harder to deal with smaller wire for a given load.

[Grizzly4x4]

13Ga for me too in all my rigs. I also agree on using full size Deans instead of the micros. The risk of a meltdown, especially with LiPo, is just not worth it.

[Stormin2u]

Been using 16ga for two years without any regrets and grateful for every ounce of weight reduction. I'm convinced lighter rigs are more competitive and you have to take those weight savings where you can get them. But I only use the micro connectors on my Micro truck.

[JohnRobHolmes]

While I certainly understand the weight savings goals, going from 13ga to 18ga saves a whopping 3.3 grams per 6" section. Not even a half ounce with two total feet of wire. Every ounce does count, I just prefer to look for weight savings elsewhere like wheel or knuckle weights. Wires can act as a heat sink for components, which is how the Tekin FXR wicks away heat from the ESC.


Just my opinion though. There is no right or wrong on the matter.

[EddieO]

See we can agree on something. I don't know what this fascination with small wire is. I understand saving weight, but less than 10 grams in the whole truck? Buy some aluminum screws....make a lexan reciever case....do something else. It becomes even more strange when you have a pair of $140 matched motors in the truck with a beefy 4s battery.........all that power wasted to save 10 grams....

Kinda like plugs in the motor circuit.....really no reason for them. I do love to see them on the trucks running 18 awg though, tiny wire to save weight and then a pair of totally unneeded plugs that ADD weight on the truck...

My advice is always the same........use the biggest wire you can fit, 13 or 14 is perfect.....plugs for the battery only and buy a good quality plug meant for power you are gonna running through it.

Later EddieO

Originally Posted by JohnRobHolmes

While I certainly understand the weight savings goals, going from 13ga to 18ga saves a whopping 3.3 grams per 6" section. Not even a half ounce with two total feet of wire. Every ounce does count, I just prefer to look for weight savings elsewhere like wheel or knuckle weights. Wires can act as a heat sink for components, which is how the Tekin FXR wicks away heat from the ESC.


Just my opinion though. There is no right or wrong on the matter.

[JohnRobHolmes]

Power junkies agree: Small wires makes for wasted power.

I use 4mm Castle bullet plugs on my motor wires. I swap electronics so much it just makes sense for me. The plugs have lower resistance than the wire, so I don't lose anything in the connection. I grew up being a cheapskate. One ESC that got swapped over many rigs. The habit never really stopped. I still only have three TorqueMaster ESCs among my 20 something crawlers.

[EeePee]

All black, 16 gauge wire for looks (most important!), and ease of soldering (not important), and it works (fairly important).

And it's more flexible, which is important in some cases.

[EddieO]

How does a gold plated bullet plug have lower resistance than the same size piece of wire? Never heard that theory before...

Later EddieO

[Charlie-III]

Originally Posted by EddieO

How does a gold plated bullet plug have lower resistance than the same size piece of wire? Never heard that theory before...

Later EddieO

Hmmm...good question. Power capacity is usually:
1-cross section of conductor (mils or wire gauge or ....ummmm....frikkin metric equiv)
2-material of conductor



Signal/comm wires are "surface voltage flow", thus total wire/wire strand surface area has an impact, coatings & type of material tend to come in 2nd.

[JohnRobHolmes]

The cross section of the plug is much larger than the cross section of the wire. 5180cm for 13ga vs. about 40,000cm for a high current 4mm plug (od 5mm of solid copper). If you haven't looked at the Castle style slitted bullet plugs give them a gander, there is very little airspace inside and the contact area is rediculous. In reality the connection won't be so good because of solder losses and connection contamination, but it is still better than wire.



Just did a little test with my four wire resistance meter. 2.1 mOhm for a 4mm plug and inch of 13ga wire. 2.6 mOhm for a section of 13ga wire of equal total length.

[indiana mudcat]

JRH and EddieO, thanks for backing up what I've always thought. Like Eddie said the guys that spend $140+ on a matched set of motors then choke it with 18ga make no since to me. Seems they also tend to be the guys that think a 480mah 30C pack is plenty, I wouldn't run that on a single motor let alone two.

Hello, my names Ed and I'm addicted to power.

[JohnRobHolmes]

Hello Ed!
Hello, my name is John Robert and my pinwheels are powered. So is my kids bike. And four of my bicycles. I'm addicted to power


A 480mah pack is plenty of runtime for a course. Plenty of power? Depends on how smooth the driver is. I bet dollars to doughnuts the national ranked drivers can out drive me no matter how much power I have.

[EeePee]

Originally Posted by JohnRobHolmes

In reality the connection won't be so good because of solder losses and connection contamination, but it is still better than wire.

You should develop bolt on bullet plugs!

[CD13]

Originally Posted by JohnRobHolmes

Power junkies agree: Small wires makes for wasted power.

I use 4mm Castle bullet plugs on my motor wires. I swap electronics so much it just makes sense for me. The plugs have lower resistance than the wire, so I don't lose anything in the connection. I grew up being a cheapskate. One ESC that got swapped over many rigs. The habit never really stopped. I still only have three TorqueMaster ESCs among my 20 something crawlers.

ME Too, Always able to unplug my esc in case I need to do a swap. I get laughed at a lot but one day it will save me.

[Manning]

How often do you power junkies run at WOT?

IMO, there's a place for getting the last fraction of a watt out of the motor/batt combo, but crawling isn't it. I just think its funny hearing about the power loss when the only time I use WOT during a comp is to get the rig flipped back over. If the rig isn't upside down, I probably never go over 2/3 throttle.

I like the smaller wire just cause it's more flexible and easier to work with, and is easier make the wiring look decent. I run 16 from the esc to the dig switch, then 18 from there to each motor, no connectors anywere except for the battery/exc connection.

[Charlie-III]

Originally Posted by JohnRobHolmes

The cross section of the plug is much larger than the cross section of the wire. 5180cm for 13ga vs. about 40,000cm for a high current 4mm plug (od 5mm of solid copper). If you haven't looked at the Castle style slitted bullet plugs give them a gander, there is very little airspace inside and the contact area is rediculous. In reality the connection won't be so good because of solder losses and connection contamination, but it is still better than wire.



Just did a little test with my four wire resistance meter. 2.1 mOhm for a 4mm plug and inch of 13ga wire. 2.6 mOhm for a section of 13ga wire of equal total length.

OK, devils advocate.......say you have a 4' diameter wire.....but the mating contact spot is .050", does this mean the connection can handle 1000amps????

Not.

It's contact area as well as wire area.

Figure the circumference of the bullet connector, that is all the amperage it can handle.

This I will argue with.