I'm confused

[Anonymous No.2508871]

I need 10AWG wires for an eBike battery pack project. Tinned copper, silicone insulation.
What seems to be the go-to in the DIY battery pack and RC world is those very flexible silicone wires, the 10AWG ones on Amazon/Aliexpress for example seem to have 1050 (!) 0.08mm copper tinned strands.

Surely those 10AWG 1050 strands must have more resistance and lower amp rating than say a 10AWG 78 tinned copper strands wire, don't they? All that tin and shit. Is the difference significant? Is the added flexibility really worth it?

[Anonymous No.2508874]

>>2508871
Would have to see what your designed steady current load is, and any other debating that may be needed.

Found this one chart that says .35 for 41+ conductors. All these charts will assume a high quality crimped connector, solder doesn't help you, crimp is better.

Might be slightly different debating for very high count like you got, but .35 is already pretty good

[Anonymous No.2508877]

>>2508874
>Would have to see what your designed steady current load is
It's an eBike so the load will vary quite a lot but will never exceed 30A, probably around 20/25A max. I'm overbuilding it by going with 10AWG just because I can. 12AWG would be fine.
Wrong pic I guess?

[Anonymous No.2508881]

>>2508877
Forgot to paste the link
https://www.coonerwire.com/amp-chart/

Looks like 12g would just hit the .35 deriving assuming 200c insulation

[Anonymous No.2508885]

>>2508881
So 1050 strands would still be a 0.35 factor like 41 strands? How is that possible?

[Anonymous No.2508887]

[Anonymous No.2508897]

>>2508881
>https://www.coonerwire.com/amp-chart/

These charts, just FYI, are only helpful as a guideline (except in cases like the NEC where it's a requirement that you follow them). They have to make a lot of assumptions about the environment the cable is in, and tend to be somewhat to extremely conservative for that reason. As an example, I was running 40A through either 14 or 16AWG speaker wire on my first ebike, and that only just got warm because it was in open air, zip-tied to the frame. That same current with the same cable buried in fiberglass wall insulation will fry it in short order.

>>2508885
>So 1050 strands would still be a 0.35 factor like 41 strands?

That isn't referring to strand count, it's referring to CONDUCTOR count. That is to say, the number of wires you have stuffed into a single conduit. They need to be de-rated because, in that case, there are multiple conductors generating heat, but limited surface area/airflow to keep them cool.


On a bike, your only major concerns are vibration resistance and voltage drop. Unless you have something unusual set up where sections of cable are very poorly cooled, your main enemies are fatigue breaking your connections and resistance effectively robbing you of expensive battery capacity. In your specific case, 10AWG, even if an unusually high portion of it is tin, is more than enough for 30A.

[Anonymous No.2508910]

>>2508897
Thanks a lot anon, this helps a lot.
>I was running 40A through either 14 or 16AWG speaker wire on my first ebike, and that only just got warm because it was in open air
So it didn't burn but weren't you loosing some efficiency though? Voltage drop / wasted battery capacity in the end?
>They need to be de-rated because, in that case, there are multiple conductors generating heat, but limited surface area/airflow to keep them cool.
Is that the "harness" rating I think I heard about?

>In your specific case, 10AWG, even if an unusually high portion of it is tin, is more than enough for 30A.
Good to hear.
Still, if you had the choice between this 10AWG 1050 strands tinned copper
https://aliexpress.com/item/1005002701853634.html

vs some made in Europe 6mm2 (between 9 and 10AWG) 78 strands tinned copper, same length but slightly more expensive, what would you pick?

[Anonymous No.2508923]

>>2508910
Any 10AWG cu wire will have an effectively identical resistance to any other 10AWG cu wire regardless of strand count or tinning. The voltage drop across wire distances we’re dealing with hobby electronics make these minuscule differences irrelevant. Go with the higher strand count because it’ll be more flexible.

[Anonymous No.2508930]

>>2508910
>So it didn't burn but weren't you loosing some efficiency though? Voltage drop / wasted battery capacity in the end?

You always burn a little energy as heat in the wires. Physics is a bitch. Barring cases where you run into thermal issues, you kind of just have to decide at what point that becomes unacceptable. If I'm remembering correctly, I was "only" at ~5% losses at full tilt in that scenario. Less is obviously better. 1-2% maximum is more typical.

>Is that the "harness" rating I think I heard about?

Not a term I'm familiar with. All I know is that it's something to consider when current-carrying conductors are bundled together, whether that's in a conduit or in free air, held together with cable ties or lacing.

>same length but slightly more expensive, what would you pick?

If not in a hurry, the high-strand one. The 78 is probably fine if I could get and wanted/needed it faster. Really, I'd like a higher strand count than that, but I wouldn't really care unless I was frequently off-road.

[Anonymous No.2508933]

>>2508930
>If I'm remembering correctly, I was "only" at ~5% losses at full tilt in that scenario. Less is obviously better. 1-2% maximum is more typical.
5% voltage drop? Just trying to figure out how you measure efficiency loss. Voltage drop is obvious, just measure what you're getting at the end of the wires but is it this the only efficiency issue you can measure?
>If not in a hurry
I'm not
>unless I was frequently off-road.
I will be
Looks like I'm good to go on the chinabros wires then. Thanks again

[Anonymous No.2508944]

>>2508933
>Just trying to figure out how you measure efficiency loss

As far as the wiring goes, it's 1:1 with voltage drop. Figure you get 50V from the battery and the cables are dropping 5V. At 20A, the battery is supplying 1000W, but the wires are using up 100W of that just heating up. The motor only has a maximum of 900W left to work with.

>is it this the only efficiency issue you can measure?
Every part of the electrical system will affect efficiency, between the battery's ESR, the welded/soldered strips used between the cells in the battery, the cables, the switches in the controller, the motor, and the various connectors used to hook all this up. You can measure all of them if you have the equipment and know how, but most of them are either out of your control or not worth worrying about. You can go as deep down that rabbit hole as you want, but the solution just always ends up being "spend more money on nicer parts", anyway.

[Anonymous No.2508948]

>>2508944
>You can go as deep down that rabbit hole as you want, but the solution just always ends up being "spend more money on nicer parts", anyway.
Yeah, I think I've already done more than enough by going with 10AWG instead of 12, making sure the nickel strips I ordered are pure nickel and going with XT90S connectors (maybe you're going to say that crimped Andersons or whatnot are better but idk, that anti spark function sounds great, but I could always change later if I want).

Thanks for everything anon.

[Anonymous No.2508955]

>>2508948
>XT90S connector

The only issue is that they use solder cups. Soldered connections effectively solidify a wire at the joint and negate the benefits of high-strand wires. You can mostly counteract the issue by securing the wires/connector as solidly as possible near the joint. It doesn't really matter if the connections are more brittle if they're prevented from moving in the first place.

[Anonymous No.2509115]

>>2508874
>>2508881
please don't breed
conductor number is different than strand number

[Anonymous No.2509117]

>>2508887
/thread

[Anonymous No.2509143]

>>2508897
>tfw using 12awg for 60A e-scooter
should probably also not be using XT60s eh

>>2508955
oh I hadn't thought about that either, I'll definitely want to bury the connector and have external strain-relief then.

[Anonymous No.2510167]

>>2508871
Do not use silicone insulation, it is shit, in degrades with time and becomes brittle.
Either use PVC or PTFE

[Anonymous No.2510169]

>>2509143
XT60 is shit, do not use XT, use spade connectors.

[Anonymous No.2510172]

>>2510169
What sort of spades do I need for 60A?

[Anonymous No.2510176]

>>2510172
Yellow ones are rated 24A, real amps.

XT60s are horrible connectors. Brass they use is brittle as fuck, contact gets shit over time and surface is much smaller than on spade.
Spades were meant for automotive and vibration stuff, xt-60 was meant for toys.

Next step is ring terminals I guess.

[Anonymous No.2510179]

>>2510167
>Do not use silicone insulation, it is shit, in degrades with time and becomes brittle.
>use PVC

Do you just have these backwards or what? Silicone is used specifically because that DOESN'T happen. PVC is the one that gets brittle over time or with exposure to a lot of oils/solvents.

[Anonymous No.2510180]

>>2510179
>Silicone is used specifically because that DOESN'T happen.
I've seen brittle chinkshit silicone wire. Also when it gets cut it has tendency of removing itself.
PVC gets brittle in 30-50 years, but not in 2 years INSIDE e-scooter with no UV.

Only pro of silicone is that it is the cheapest temperature-resistant wire. That is it.

[Anonymous No.2510196]

>>2510180
The other pro of silicone is that it doesn't deform plastically. It will always flex back to its original shape. Good for cables where high flexibility is useful, like for a soldering iron cable or computer mouse cable.

I've seen DMM leads in the field that last like 5-10 years (until they break because some retard chomps them with a toobox lid or cutters or some shit), with UV exposure, and they're silicone. Think it's just a chink thing. Chinky silicone insulation is also really fucking soft, like soft enough to strip the insulation with even short fingernails. I've got some higher-quality silicone wire that doesn't do that.

PVC goes gooey pretty easily if it's around even minor solvents.