4ga. cables. does it matter how many strands?

[fstatum]

I'm seeing 4ga. battery cables in various numbers of strands anywhere from as little as 19 strands to as many as 133 strands. Seems the auto parts stores are mostly offering 70 strands in there cables. Other than flexability is there any other pluses or minuses?

[yellow36vpds]

fstatum,

From what I have read in other posts here, the more strands the better. It helps transfer the current in a more efficient manner.

[usgicollector]

Originally Posted by fstatum

I'm seeing 4ga. battery cables in various numbers of strands anywhere from as little as 19 strands to as many as 133 strands. Seems the auto parts stores are mostly offering 70 strands in there cables. Other than flexability is there any other pluses or minuses?

Use only welding or locomotive lead, not battery cables.

[teecro]

Originally Posted by yellow36vpds

fstatum,

From what I have read in other posts here, the more strands the better. It helps transfer the current in a more efficient manner.

Yes to a point but there is also a point of diminishing returns too. In high frequency applications there is benefit but it does not make near as much difference here with the DC application. Get a finer count for flexibility and long term durability but don't break your bank doing it either...

[scottyb]

Use a neoprene jacketed welding lead. You will get acid resistant coating and 400 plus strand count.

[Revolution]

Originally Posted by teecro

Yes to a point but there is also a point of diminishing returns too. In high frequency applications there is benefit but it does not make near as much difference here with the DC application. Get a finer count for flexibility and long term durability but don't break your bank doing it either...

Although we use dc power, most controllers use pulse width modulation to limit speed and curent. At the switching speed of modern controllers the dc voltage behaves a bit more like high frequency ac power. I think alltrax is at 18khz. So I would recommend huge strand count welding cable.

[JohnnieB]

Originally Posted by teecro

Yes to a point but there is also a point of diminishing returns too. In high frequency applications there is benefit but it does not make near as much difference here with the DC application. Get a finer count for flexibility and long term durability but don't break your bank doing it either...

The output of the speed controllers in DC carts is PWM (Pulse Width Modulation) rather than straight-line DC, and the frequency of the pulsed DC is in the 18kHz range, so the skin effect is very significant.

The minimum strand size for 18kHZ is about 30 AWG, which is about 374 strands for a 4Ga cable or about 625 strands for a 2Ga cable.

There is still some skin effect loss with 30 AWG at 18kHz, so while cables constructed with 32 AWG and 34 AWG strands may be more expensive, they are also more efficient.

Botton-Line: Cables designed for moving DC current and low frequency AC (60Hz) are not suitable for speed controller applications.

[scottyb]

Originally Posted by JohnnieB

The output of the speed controllers in DC carts is PWM (Pulse Width Modulation) rather than straight-line DC, and the frequency of the pulsed DC is in the 18kHz range, so the skin effect is very significant.

The minimum strand size for 18kHZ is about 30 AWG, which is about 374 strands for a 4Ga cable or about 625 strands for a 2Ga cable.

There is still some skin effect loss with 30 AWG at 18kHz, so while cables constructed with 32 AWG and 34 AWG strands may be more expensive, they are also more efficient.

Botton-Line: Cables designed for moving DC current are not suitable for speed controller applications.

Can we stickie this?

[teecro]

Dualy noted... Thanks for the education.

[kojo]

fstatum, I made my 2 gauge cables from 34awg 1650 strand count welding cable and it's super flexible. They've never gotten to warm with me.