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Conductor Current Ratings

I’d like to make an easy-to-find list of current ratings for esk8 use.

If anyone has edits, corrections, experience, or thinks it can be better, please describe what you think should be changed. :smiley:

Spreadsheet/source available on request; PM me your email address.

Popular esk8 sizes in bold.

This chart is labeled for continuous and not instantaneous. You can pretty much double every number for instantaneous, for a couple seconds or less.


Thanks @sebaszz

Thanks Lund Instrument Engineering


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What is the length that’s calculated with for the tinned braided copper .025" wide?

Maybe include voltage/power loss? :thinking:

Length of all materials is “less than one meter, for esk8 use” :smile:

So, the length of a longboard maximum. Obviously, shorter is better.

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I was thinking detailed ratings like that are available but I wanted a condensed, easy-to-use, especially for n00bs format.

This is specifically-as-relating-to-esk8 only and not intended for other uses.

There is a calculator for all that if you follow the Lund Instrument Engineering link above

I was doing something in which I was getting close to 2 meters with braid. That’s why I’m curious. Maybe I’m thinking about wiring it wrong though…

Shooting from the hip, I would limit that to 30A continuous, 55A peak.

I would strongly recommend silicone-insulated fine-stranded copper wire for that. It will hold up to vibrations much better.

It’s using compression packs.

12s4p made out of 1s4p packs

Alternate bridged groups and then snake one long length of braid through. I’ve been worried about rating of the 3/8 braid I was going to use the entire time because of it.

Might as well add common connectors. Jst xh/ph, bullet, xt, dc barrel, etc.

Never mind the extremely informative and concise post, what I want to know is why the double zero in noobs. Is it because noobs looks a bit like boobs if you use 2 o’s

Brian you old perv


Honestly you should add a proper ampacity calculator

For example my Evo battery for all series connections runs two 14guage wires as series connections.

14guage wire at 54.6volts(full charge 13s) can support ~97amps in at a 1foot length, My series connections are 4inches and doubled… so real ampacity of my 4inches of doubled 14ga is probably close to 400a instantaneous capable.

Length matters, ampacities grow exponentially as the length and overall resistance of the wire decreases.

Most of those numbers are way off compared to the actual lengths we use, and following the chart to a T will result in alot of extra weight in copper and space lost for no good reason.

BUT, the chart is a great place to start if you are not sure… so good post @b264


You sir, are a Gentleman and a Scholar.


That chart for nickel strip is a bit underated just as every other chart is, one strip of 0.15 x 10mm pure Nickel can handle a lot more than 6.71 amps without heating up.

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Aye, also depends on the length, those are bare estimates, battery to battery center is 18mm on 18650s, and 8-14mm of that is mated with the battery casing, leaving 10-4mm of nickel between each battery, the ampacity is quite high. (Numbers are accounting for positive vs negative side and pvc wrap)

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If you follow the Lund link in the second post, there is one :smirk:

This chart is labeled for continuous and not instantaneous. You can pretty much double every number for instantaneous, for a couple seconds or less.

I added this to the first post.

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Good thread. One thing i would like to know is the amount of current going through motor phase wires.

Lets say your motor max is 90a but you have 3 phase wires. is it a simple 30a per wire? or does it cycle 90a per wire very quickly?

It’s 3 phase AC so it cycles between all three in a rotation. Each one is probably “on” for two-thirds of the time.

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