Dual battery systems

6mm?? diameter of the wire and insulation or 6square mm cross section.
If it's the former then the cable is too small.

You will get some volt drop in any cable though. Especialy if it's drawing high amps.

6mm "Auto" cable is a misnomer. It's got to be a minimum of 6mm squared in copper area. Bigger is better. There are resistance tables somewhere that will tell you the voltage drop expected per 1 metre of cable (Do a google on it). 6 metres is far too long. Can you get the battery up into the front of the tub, closer to the action?

Mick

Gitto,

Cable diameter is the most likely cause of your problem.

I have an AGM Battery mounted in the tub of my Colorado and have no problems.
I installed a Sidewinder Flyer to house the battery and this system comes complete with cables, anderson connectors and a built-in isolator. The cable is also 6m long but 100mm2 dia.


Bill.

Try asking at Battery World for some 6 B & S cable They will know what you mean

Take a thick wallet Its around $10 a metre .

HI
I have put a second battery in the back of my rodeo (due to the ABS same as you). I have a 120amp isolator and ran 4b&s cable. I put in 2 60amp fuses (one at the isolator and one before the Aux battery. I was getting a voltage drop of about 1 volt. I took my fuses off and tried it, then only got a .15 voltage drop (much better). i replaced the fuse at the aux batt end with a 100amp circuit breaker and didnt bother about a fuse at the isolator end. Still only get a .15 volt drop.
The type of fuse i used is this type
fuse
Perhaps the terminals were too thin. im not sure, all i know is that taking them off solved my problem.

My suggestion based on my experience is make sure your fuse and associated wiring and housing, plugs, terminals etc are adequate, even though they may have a high amp rating they may still put unwanted resistance in the circuit if not of good quality.

And like others have said, the 6b&S is the minimum, 4 is better. And make sure you have a good earth, a full length earth back to main battery of same size cable is best (but adds expense)

hope you sort it out.

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There ya go !!

Cheers

Steve

I use 1 B&S and get no voltage drop, one way to save money but loose voltage is fit cable that is too skinny, remember there's no such thing as too thick :)

Maîneÿ . . .

Thanks for all the help I now have some areas I shall check out and see what I come up with.