Traxide SC80 Battery Controller

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Originally Posted by Graeme

IMO connecting the aux battery's earth to the body is better than using a cable connecting to the primary battery because there will be no voltage drop by connecting to the body but will be if using a cable. There's going to be voltage drop from the positive cable without adding to it with an earth cable. Don't connect to the D2's chassis though because it isn't positively earthed ex-factory, only via steering linkages etc although fitment of a winch with its earth connected directly to the battery usually overcomes this.

A CB or fuse is required at each end of the inter-connecting power cable because if there's a short circuit part way along, neither battery must be able to provide unrestricted current so as to prevent a fire.

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Graeme,

I used the earth point on the DS D pillar (under the brake light).

So, is 7.9mm cable sufficient for the earth (it's only 350mm long) or do I need to go to 13.5mm cable here as well?

Cheers,

Franz

Quote:

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Originally Posted by Pedro_The_Swift

just use the voltage drop calc to find your cable size over known distance


Voltage Drop and Cable Size Calculator

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Thanks for that Pedro.

How do I determine the maximum current demand? When my fridge fires up it will draw 5 amps plus for short periods. If I fire up the ARB compressor, it draws about 8 amps or more.

Cheers,

Franz

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Originally Posted by austastar

My you beaut tightly connected Earth return via the seat rail bolt wasn't so you beaut.

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That's because it wasn't a dedicated earth bolt - it was holding at least 2 pieces of metal together with an unknown/unreliable surface between them.

Quote:

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Originally Posted by Franz

I used the earth point on the DS D pillar (under the brake light).

So, is 7.9mm cable sufficient for the earth (it's only 350mm long) or do I need to go to 13.5mm cable here as well?

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Hi Franz,

IMO that's a good earth point.

I cannot advise on cable current carrying capacities.

Quote:

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Originally Posted by Franz

Autobarn, SCA, Repco or caravan accessory suppliers.

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Ok - I will have to go visit them again - never seen real heavy stuff at any of the auto shops - was just at SCA and they do not have anything heavy like I have on my van.

Cheers

Garry

Quote:

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Originally Posted by garrycol

Ok - I will have to go visit them again - never seen real heavy stuff at any of the auto shops - was just at SCA and they do not have anything heavy like I have on my van.

Cheers

Garry

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Also try Battery World.

Or Jaycar

Jaycar Electronics - Search results

Tony

Don't know how true it is but I was always told that earthing to the body etc promoted corrosion. It was always better to earth back to the battery.

Is this an urban myth:eek:

a tip for your main cable circuit breakers and fuses

connect a small light (or bi directional led with a suitable resistor) across each one, when one lets go it will provide an indication that the thing is doing its job and has gone open circuit.

Quote:

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Originally Posted by Franz

Thanks for that Pedro.

How do I determine the maximum current demand? When my fridge fires up it will draw 5 amps plus for short periods. If I fire up the ARB compressor, it draws about 8 amps or more.

Cheers,

Franz

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Depending on the model of compressor it will draw more than that, once up around 30 psi 20+ amps is normal

Rule number one with cabling is if in doubt go larger, larger wont hurt, smaller will.

If you are running a charging style cable to a camper or similar there are better ways of doing it such as the REDARC BCDC charger. Check out REDARCS website for lots of useful info on wiring to.