12 replies to this topic

[Nic]

as title anyone know the mm2 of the battery cable? looking at ordering some cable and making my own but not sure which size to get.
cheers

[charie t]

Can you not get a tape across the one you have?
8mm will be ample thickness to supply all the power needed for a mini

[Dan]

You need at least 25mm, the bigger the better really. At 25mm you're only dropping half a volt due to the cable under starter load which is roughly acceptable, the resistance of the battery will be doing far worse. Down at 16mm you are dropping a volt due to the cable under the starter stall current which is starting to become significant.

[charie t]

You need at least 25mm, the bigger the better really. At 25mm you're only dropping half a volt due to the cable under starter load which is roughly acceptable, the resistance of the battery will be doing far worse. Down at 16mm you are dropping a volt due to the cable under the starter stall current which is starting to become significant.

25mm square you mean dan? 1"ish thick cable? We used that to run 2 60hp 3 phase electric motors at the farm

[Dan]

Yes, as that's what the OP asked! Cable is always sized by it's CSA, not diameter. The diameter depends on how many strands of what size make up the total bundle, what type of insulation it has and who made it so cables are all different. While this sort f info determines how suitable a cable is for its installation it has no bearing on its electrical performance. Only the total CSA and length matters for current carrying ability.

[charie t]

Cables are always sized by it's CSA, not diameter.

Everyday is a school day as they say

[Nic]

There is some 35mm2 cable available shall i go for that then or is that too thick?

[Dan]

Thicker is better, as long as you can get it made up with the right fittings at each end or can do it yourself and it fits through the grommets it'll be fine.

[Nic]

Great thanks for your help dan.

[SolarB]

Electrically bigger is better (or rather smaller is worse) but if it's too thick it won't fit in the cable tray under the floor pan. I bought some a while back for my car from Polevolt, if you can wait until this evening I'll find the receipt.

[tommy13]

Table here which may be of use, giving cross sectional area, amperage and outsuide diameter of various battey cables.
http://www.vehicle-w...atterycable.php

[Bungle]

You need at least 25mm, the bigger the better really. At 25mm you're only dropping half a volt due to the cable under starter load which is roughly acceptable, the resistance of the battery will be doing far worse. Down at 16mm you are dropping a volt due to the cable under the starter stall current which is starting to become significant.

25mm square you mean dan? 1"ish thick cable? We used that to run 2 60hp 3 phase electric motors at the farm

the other thing to think about is loose a couple of volts at 415v and it doesn't matter loose a couple of volts at 12v and it's a big difference

[AndyMiniMad.]

Also Cars run on Direct Current and domestic/Industrial supplies are Alternating Current. It makes a big difference to the amount of power you can run up a certain cross sectional area of cable over a measured distance.