Thread: Amplifier cable vs. Battery cable

Lighter because it is thinner in cross section and often doesn't contain as much copper. Is often described as 'oxygen free"

Might be OK for remote fridge plugs but it certainly isn't battery cable.

I wouldn't. DL

I do actually use the thickest 'power cable' stuff that Jaycar sell (solid red outer) from alt to starter battery and from Redarc dual battery controller to charge aux battery, neither of which is a serious application........ like flowing lots of amps.

No probs after 10 years

DL

Welding supplies generally have what you need at a good price (except from boc), I use a lot of this in cars and stand alone solar jobs

Hi Tank and while it can be used, amplifier ( speaker ) cable is not suitable as dual battery cable.

If it is 6 gauge then it is the same cross sectional area as 6 gauge or 6B&S automotive cable and the copper is far better quality in amplifier cable.

The copper is not the issue, it's the insulation.

Clear speaker cable insulation is not designed to carry the same "CONSTANT" current loads that automotive cable is designed to tolerate.

It is fine for very low current loads but not for carrying the currents generally found in dual battery systems.

Clear speaker cable will melt at a lot lower current load and is therefore not suitable for dual battery use.

Drivesafe and the others that gave help, Thank you all.
The system I am referring to is on my truck, power from the 120 amp. alternator is fed to 2x 12v. batteries giving 12v. to the electrical system, the engine is a Diesel.
My Son has setup 4x 12v. electric fans (2x sets of Falcon thermo fans) to cool the engine, he has used about 1/4"/6mm dia. wire, which is AMP wire with the clear red plastic insulation.
It connects to one of the dual batteries (2x12V.) and travels about 2 metres to a set of 4 relays which runs the fans, we can run 1 set (of 2) fans or the full 2 sets(4 fans all up), under heavy load the alternator is loading up and the single V belt starts to slip.
Would heavy duty battery cable wire direct from the battery to the relays help and what size wire should be fitted between the alt. and the batteries, any extra info would be appreciated, Regards Frank.

Originally Posted by drivesafe

Hi Tank and while it can be used, amplifier ( speaker ) cable is not suitable as dual battery cable.

If it is 6 gauge then it is the same cross sectional area as 6 gauge or 6B&S automotive cable and the copper is far better quality in amplifier cable.

The copper is not the issue, it's the insulation.

Clear speaker cable insulation is not designed to carry the same "CONSTANT" current loads that automotive cable is designed to tolerate.

It is fine for very low current loads but not for carrying the currents generally found in dual battery systems.

Clear speaker cable will melt at a lot lower current load and is therefore not suitable for dual battery use.

Frank,
Changing the wire will not reduce the load on the alternator. This is not a wiring problem, but a mechanical/electrical problem. If the alternator is not up to the job it needs upgrading - if it is, but the belt is slipping, then you need to ensure that the drive belt and pulley are all in good condition, properly aligned, and the tension correct. If these are all OK and it is still slipping, perhaps you will need to go to dual belts, or another alternative may be a small increase in the diameter of the alternator pulley - this will reduce the alternator rpm, which will increase the minimum rpm for charging, but increases the belt contact area. Or go to dual belts.

As Drivesafe has hinted, the major problem with speaker leads for wiring in cars is, assuming copper area is equivalent, the insulation. Speaker leads are intended to be as flexible as possible, and are assumed to be used in a maximum temperature that is comfortable for humans (e.g. <35C), without a current sufficient to cause significant temperature rise. And not subject to any significant movement.

Automotive wires are designed to be used in an environment where locally temperatures may be as high as engine running temperature (up to 100C at least), with temperature rise of perhaps 30C due to current flow above this. They are also designed to live in a high vibration environment, and to be resistant to mechanical damage.

The insulation of automotive wiring is tough, resistant to oil, heat and mechanical damage, and is stiff as a result. The insulation of 'speaker wire' is designed to be flexible and attractive to look at. As a result it is soft, easily damaged, and not resistant to heat and oil.

Hope this helps,

John