Is this cable thick enough?

[John_D4]

D4 2013

I’m running 8b&s from the spare battery (with a 40 amp fuse at the battery), (traxide kit) to the rear jack compartment. From there it splits with 1 x 1/2 going to the tow hitch for the camper or solar input. The other 1/2 (still 8b&s) goes to the rear a/c locker. My aim is to put in 2x Anderson 50amp sockets. 1 to power the fridge (5 amps?), and the other to power the ARB compressor.

Is 8b&s thick enough or should I change it for 6 or 4b&s? I’ve still got access via the hole near the accelerator pedal as the other one near foot rest is full.

[Tombie]

For that requirement it’s more than enough.

[Homestar]

Yep, plenty big enough.

[John_D4]

Great. Thanks guys, you’ve saved me a couple of hours of wiring

[DiscoMick]

Sorry if I misunderstood, but when you say it's going to the camper, is that just to run lights, or are you charging a battery?

[Tombie]

Sorry if I misunderstood, but when you say it's going to the camper, is that just to run lights, or are you charging a battery?

Perhaps read the post [emoji41]

[AK83]

Perhaps read the post [emoji41]

Sounds like it could be both, depending on circumstances.

John said run to the camper or solar.

Run to the camper one could reasonably assume means to power some stuff in the camper.

.. or solar obviously.

I'd say the fuse sounds a bit small for the compressor AND fridge AND if powering anything in the camper at any point.

IIRC most or some ARB compressors themselves require a 40A fuse. Some can draw over 60A themselves, but I think these are the twin pot high volume types.
If it's a regular blue bodied compressor from them, it can run at close to 35A itself. Obviously not all the time, and would be only when under load pushing those last few psi into the almost inflated tyre .. etc.

[PhilipA]

Yes, I was going to make the same point about the amp draw. If you use 4B&S you will also future proof your installation as in the future you may wish to upgrade something in the camper or car. I also suggest you use a maxi Fuse or similar to allow a higher fuse value than the standard blade fuse.

I have run 4B&S to the back as my compressor runs to 50amps plus my Engel, and now plus my 3way fridge in the caravan and 20/20DC/DC charger in the caravan.

The approx 10B&S leads get quite warm from the Anderson plug to the compressor.

I took note of the comments to my previous thread and also shortened my run of 8B&S by about 1.5 metres and my 4B&s by 1metre.
Regards PhilipA

[John_D4]

The only thing in the camper that draws power while we’re driving is the 65lt 12v fridge. There’s a poor example of a solar panel on the roof, and 200ah of lead acid batteries. I think that the wiring from drawbar to batteries is probably 8b&s (as guess).

I’ve been on many trips to the desert since February and I’ve run the compressor while the camper was hooked up (car has a 2nd Waeco 50lt set to freeze) and I’ve never blown a fuse yet. At this point I’m unplugging the Waeco to plug on the compressor as I still need to splice in a 2nd Anderson for the compressor.

[John_D4]

On the D2 that I sold I ran 3b&s from the spare battery to the campers battery (sold that camper as well). Had no voltage drop, but with the current setup I get to the Camp site with over 13v in the camper batteries also.

[drivesafe]

Hi John and sorry but that cable is not thick enough.

The reason you did not blow the 40 amp fuse is because the THIN cable run was so long that even if your two house batteries were dead flat, the voltage drop caused by the 8B&S ( 7.9mm2 ) cable would dramatically reduce the current draw of the batteries.

To increase the charge current a battery will draw, you MUST increase the voltage at the battery. 8B&S causes the revers.

I have seen house batteries draw 60+ amps down 6B&S ( 13.5mm2 ) cable, in the same situation.

For optimum charge performance, you should use at least 6B&S and while thicker cable would give better results, they would be very small improvements over 6B&S. So up to you!

With 6B&S, you can safely run 70 amp fuses but no bigger.

[John_D4]

So just to be clear, running the ARB compressor, Waeco 50lt 12v, 65lt camper 12v fridge and keeping the 2 x 100ah of camper batteries charged will be achieved with 6b&s?

[drivesafe]

So just to be clear, running the ARB compressor, Waeco 50lt 12v, 65lt camper 12v fridge and keeping the 2 x 100ah of camper batteries charged will be achieved with 6b&s?
I should have asked if the 65Lt fridge is a compressor type or 3 Way type.

If it is a compressor type then yes, the 6B&S will be fine.

If the 65Lt fridge is a 3 Way type, then you will need to run a separate supply, from the cranking battery all the way to the 3 way fridge and I would suggest using 8B&S for the fridge supply and fit a "Fridge Switch" to automatically control the power for the fridge.

Just to give you an idea of the difference the cables sizes make, I carried out some tests many years ago and this is what your can expect to get.

With a cranking battery voltage of 14.0v and a run 10m of 8B&S ( 7.9mm2 ) cable with a 40 amp load at the other end, the voltage was 12.09v. Just no where near enough to charge the batteries in any form of reasonable time. And forget the fridge.

With a 10m run of 6B&S ( 13.5mm2 ) cable and an end load of 40 amps, the voltage was 12.93v, and thats nearly a volt difference and would make for much faster recharging.

Even adding an additional load of 5 amps for the fridge, the 6B&S would be at 12.8v while the 8B&S would be down to 11.82v

[John_D4]

Both fridges are 12v compressor fridges. I’m personally not a fan of the 3 way fridge.

For future proofing my setup in case I decide to go lithium in the camper (with a DCDC next to the camper batteries) when the 2x100lead acids expire, I’m wondering if 4b&s might be the way to go? Thoughts

[drivesafe]

Hi John and going up in cable size is never a problem, it is just cost verses outcome.

If you do not mind spending a little more, then do so.

Keep in mind that you will either need to reduce the copper thickness at the Anderson plug, to be able to use the standard 50 amp Anderson plugs or move up to 120 amp Anderson plugs.

[John_D4]

Any idea what cabling route is possible for 4b&s in a D4? The existing 8b&s goes through the firewall grommet and out of the cabin at the rear drivers lights.

[drivesafe]

Any idea what cabling route is possible for 4b&s in a D4? The existing 8b&s goes through the firewall grommet and out of the cabin at the rear drivers lights.
4B&S can go the same route.

[PhilipA]

I ran mine along the RH chassis rail then into the RH area behind the vent by using a hole behind the taillight into that area.

Mine is zip tied to the chassis and wrapped in split tube.

It terminates into a distribution block from 4B&S to 8B&S in there with 8B&S to the 2pin 50 amp plug to the caravan from there also through a hole drilled behind the taillight.
Regards PhilipA

[drivesafe]

I ran mine along the RH chassis rail then into the RH area behind the vent by using a hole behind the taillight into that area.

Mine is zip tied to the chassis and wrapped in split tube.

It terminates into a distribution block from 4B&S to 8B&S in there with 8B&S to the 2pin 50 amp plug to the caravan from there also through a hole drilled behind the taillight.
Regards PhilipA
In a D3, D4 and RRS of the same models, you should never run cable along the chassis rail, because if the vehicle has to have any work done on the motor or turbos, they lift the body off.

And when they do this, any cabling on the chassis rail is ripped out and if the cabling goes into the rear cargo area, it will damage panelling as well when the cable is ripped out.

It's a VERY expensive short cut, that is totally unnecessary because these vehicles are the easiest vehicles I have ever worked on to run cabling through the vehicle, WITH LAND ROVERS own wiring loom.

Do it right and save a lot of money.

[PhilipA]

Agree. I got confused by earlier references to D2.
Regards PhilipA

[John_D4]

8b&s will be large enough to run the Waeco cf50. Maybe I’ll leave the fridge wiring in place and from the new feed to the trailer, splice a new 6b&s feed to the compressor.

Is there a reason why I can’t use thick welding cable instead of standard automotive cabling? I find welding cable more flexible

[Tombie]

All my under bonnet install is welding cable.

[drivesafe]

Is there a reason why I can’t use thick welding cable instead of standard automotive cabling? I find welding cable more flexible
While welding cable is exactly the same size and current carrying capacity as automotive cable, there is the cost difference.

The D4 is so easy to run cable through that it really is unnecessary to use welding cable but doing so will not harm anything.

[Tombie]

While welding cable is exactly the same size and current carrying capacity as automotive cable, there is the cost difference.

The D4 is so easy to run cable through that it really is unnecessary to use welding cable but doing so will not harm anything.

Agree. In my case it was curve radius on some areas where it came into its own.