TESTED best WIRE SIZE for ebikes application + heat shrink

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Doctorbass
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TESTED best WIRE SIZE for ebikes application + heat shrink

Post by Doctorbass » Aug 31, 2011 9:01 am

Hello,

Wire size generally refer to current rating.. not power..

In low-medium voltage area, ( i would say 1000V or less) the volt just refer to the insulation of the wire...

on Electric vehicule no mather the volt or power you have, the wire size will be selected according to the current that travel thru it.

That is why you can pass 1000Watts in a tinny 24AWG wire size.. ( 1A at 1000V for exemple)


The current rating of the wire depend of many factors, like:

-Wire conductive material, copper, aluminum, etc
-the environment where it is used ( in a box, or suspended in the air).. etc
-the skin material of the wire, silicon, teflon, pvc etc

A wire dissipate heat when current travel thru it. The amount of heat is proportional to the amount of current, not power.

The heat limit is depending on the wire insulation skin. Ex, 200degreeC silicon wire can take more heat ( more current) than the pcv skin wire that are made for 105 degree C max. It is also depending on how easy it can evacuate the heat it produce. If it is confined in a box or in a cable (bundle of wire) his current rating will be lowered. on another hand, if it is exposed to blowed air ( box with blower or suspended around an ebike frame) the current rating will be favorized.

Heat lost is not necessarely a good thing.. for sure it is better to choose a wire with less ressistance that wil dissipate less heat ( bigger wire).. but in RC world, the weight is something important and copper weight alot! so they preffer lighter wire ( smaller wire)

The quality of the wire is also important. Poor quality wire will have less conductive material and bigger skin than quality wire. IT CAN BECOME DANGEROUS so pay attention to that!

Another factor to consider is the current peak duration.

On an electric bike that run let say 25A continuous or average but that burst 200A 5% of the time for short 4-5 sec burst, a gauge 8 wire is enough.

Pay also attention to the connector!!.. the connectors like the good popular Anderson powerpole need the appropriate wire size to carry their max current rating!

The max current rating of these connectors depend on how they can dissipate the heat they produce due to the contact heat lost. The heat their contact produce dissipate thru the wire conductive part and the bigger it is the more heat they will evacuate from the contact.

My personnal Thumb rules:

On my experience, a good crimped and or soldered Anderson Powerpole PP30 connector can take 30A continuous ( burst to 70A) when installed on a gauge 12 wire and 40A( burst to 100A) on gauge 10 wire.

The also popular SB50 Anderson connector rated for 50A can take 75A continuous( 250A burst) on gauge 8 and 100A on gauge 4 ( burst to 400A)

The quality of the crimping, contact orientation ( great parallel match orientation on both connector) and wire size and quality are all important factors

The Turnigy 12, 10 and 8 gauge wire are surprisingly good wire quality and the very high number of stands they have make them flexible and to tend to have more conductive material for the same cross sectional area than other same size existing wire.

Doc
CURRENT PROJECT: 2WD duo MXUS/Max-E ebike 32kW
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Ypedal
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Re: TESTED best WIRE SIZE for ebikes application

Post by Ypedal » Aug 31, 2011 9:37 am

For the newbs scratching their heads

Current = Amps

regardless of voltage, it's the Amps that determine the wire gauge you need. 8)

+1 for the Hobbyking silicone wire, i love the stuff !!! I always order a few extra meters on every shipment !
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Re: TESTED best WIRE SIZE for ebikes application

Post by Doctorbass » Aug 31, 2011 11:19 am

Ypedal wrote: I always order a few extra meters on every shipment !
+1

It would be nice if they could have some 6 gauge wire!

:wink:
CURRENT PROJECT: 2WD duo MXUS/Max-E ebike 32kW
https://endless-sphere.com/forums/viewto ... =3&t=65764
-Fastest speed record 117 km/h on flat
-Fastest 1/4 mile@ 114km/h on flat and 16.316 sec
-Succeded to haul a 19200 pounds schoolbus!
113kmh Gianthttp://www.evalbum.com/3406
Mongoosehttp://www.evalbum.com/1947
YOUTUBE---https://m.youtube.com/user/Doctorbasss
http://twitter.com/DocbassMelancon
I speak FRENCH and english

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Re: TESTED best WIRE SIZE for ebikes application

Post by amberwolf » Aug 31, 2011 3:40 pm

Question:

Since the electrical insulation on the wire also insulates thermally, is one type of insulation typically better for heat dissipation than another?

I.e.: Is the thinner Teflon insulation typically better or worse at heat dissipation than the thicker Silicone insulation, given that both are commonly used on higher power bikes as phase and battery wires?

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Re: TESTED best WIRE SIZE for ebikes application

Post by Ypedal » Aug 31, 2011 4:26 pm

PM sent to me by casschr1 regarding 6 awg silicone wire !!! 8)
cassschr1 wrote:2 nd page little past halfway down tue aug 2 8:50 am
https://endless-sphere.com/forums/viewto ... 31&t=30176
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Re: TESTED best WIRE SIZE for ebikes application

Post by Doctorbass » Sep 01, 2011 8:45 am

Ypedal wrote:PM sent to me by casschr1 regarding 6 awg silicone wire !!! 8)
cassschr1 wrote:2 nd page little past halfway down tue aug 2 8:50 am
https://endless-sphere.com/forums/viewto ... 31&t=30176

Ok, it would be nice if they woudl gave the SAME number of strands than the turnigy.. because it make a HUGE difference!!

Silicon wire does not really mean they have very high strands number..

turnigy is difficult to beat for that...
usually they are called ULTRA FLEXIBLE sililcon wire..

I ordered some 6 gauge from powerex.. for 75$ of "ultra flexible" 6 gauge cable... when i received it i was dissapointed to see they are just like normal industrial cable with moderate strands and not so flexible ...

I would say that wire like Turnigy we like so much have these caracteristics:

- Silicon skin as soft and really similar to the one of silicon tubing in hospital ( just like the one on the stetoscope to listen the heart)
- ULTRA VERY EXTRA HIGH... strands number !!! usually each strands are just as small as a human hair!!
I mean so small than it is impossible to puncture your skin with them.. (like it happen with standard wire sometime...)
These wire are ultra dense of copper and their resistance is really low due to the low air gap due to ULTRA high number of strands.

Doc
CURRENT PROJECT: 2WD duo MXUS/Max-E ebike 32kW
https://endless-sphere.com/forums/viewto ... =3&t=65764
-Fastest speed record 117 km/h on flat
-Fastest 1/4 mile@ 114km/h on flat and 16.316 sec
-Succeded to haul a 19200 pounds schoolbus!
113kmh Gianthttp://www.evalbum.com/3406
Mongoosehttp://www.evalbum.com/1947
YOUTUBE---https://m.youtube.com/user/Doctorbasss
http://twitter.com/DocbassMelancon
I speak FRENCH and english

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Re: TESTED best WIRE SIZE for ebikes application

Post by Ypedal » Sep 01, 2011 10:54 am

I am posting on other's behalf since not everyone ( must be part of the Guru group ) can post in tech reference area.. :wink:
wojtek wrote:i am happy to send free samples of my wires to the Gurus who would like to test them and put some comments on them.

:)
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Re: TESTED best WIRE SIZE for ebikes application

Post by Doctorbass » Sep 01, 2011 11:00 am

Ypedal wrote:I am posting on other's behalf since not everyone ( must be part of the Guru group ) can post in tech reference area.. :wink:
wojtek wrote:i am happy to send free samples of my wires to the Gurus who would like to test them and put some comments on them.

:)

Perfect.. thanks I did not know that the forum was divided in two level? :o

Doc
CURRENT PROJECT: 2WD duo MXUS/Max-E ebike 32kW
https://endless-sphere.com/forums/viewto ... =3&t=65764
-Fastest speed record 117 km/h on flat
-Fastest 1/4 mile@ 114km/h on flat and 16.316 sec
-Succeded to haul a 19200 pounds schoolbus!
113kmh Gianthttp://www.evalbum.com/3406
Mongoosehttp://www.evalbum.com/1947
YOUTUBE---https://m.youtube.com/user/Doctorbasss
http://twitter.com/DocbassMelancon
I speak FRENCH and english

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Re: TESTED best WIRE SIZE for ebikes application

Post by steveo » Oct 11, 2011 10:06 am

I just ordered some 8 guage; 12 gauge; 14 gauge black & red wire from h/k;

I will be doing all wiring on my trike & ebike with 8 gauge.....

can't wait to clean up the wiring job... something always on my to do list; but i never get around to doing it

-steveo
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Re: TESTED best WIRE SIZE for ebikes application

Post by spinningmagnets » May 16, 2014 7:13 pm

6-AWG is a little fat for even the most demanding applications, but when listed as "bulk welding cable" it is only $1 a foot:

https://endless-sphere.com/forums/viewto ... 11&t=59899

For temperature sensors, small 30ga wire should be adequate, but teflon insulation is recommended due to the heat involved. Here is on eplace to get it that has been used by several ES members. edit: I have gone to using thicker 24-ga wire for halls and temp sensors, because...anything smaller is very hard to manipulate with my fat fingers when crimping or soldering.

http://www.powerwerx.com/wire-cable/ptf ... -wire.html

Heat shrink insulation

For any wire that is exposed to the weather, use 3:1 heat shrink, marine grade (for boats), because it has heat-activated glue that truly seals up the wire joint. Anything indoors (or inside the battery bag) I use the dirt-cheap Hobby King heat-shrink (typically 2:1 shrink ratio, if it starts out at 4mm diameter, it ends up at 2mm diameter). I even use Hobby King heat-shrink to change the color of the last inch of a wire (by the connector).
But...what size to order for a specific job?

On the Hobby King web-catalog, scroll down the left-side column and go to "Hardware & Accessories", then "Shrink Tube"

Here are their "relative" sizes, metric to inches.

mm__inches
0.8___
2_____
2.3___3/32
3_____1/8
4_____
4.5___3/16
5_____
6_____1/4
9_____3/8
10____
10.5__7/16
12____1/2
14____
16____
19____3/4
20____
25____
25.4__one inch
30____

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