Thread: How NOT to wire up your new RR for towing!

Sorry folks, this is a bit long winded.

The middle of last week I received a phone call from a new Range Rover Vogue owner, who had just had a some what heart stopping situation occur.

The Sydney resident was returning from Queensland after picking up his new Caravan.

Just north of Bulahdelah ( north of Newcastle ), while cruising at 105 KPH, his caravan electric brakes locked on, bringing him to a smoky and abrupt stop.

This incident was the result of a number of erroneous dual battery installations.

Before taking delivery of his new Range Rover Vogue, thinking he was doing the right thing, he organised for the Sydney based Land Rover dealership to install a power supply ( not a dual battery system ) to allow his RR to charge his new Caravan's house battery while driving.

This was his first, and by far, potential the most dangerous part of his fault riddled install. More on this later.

Then, as a means of allowing the house battery to be charged while driving, but to isolate the cranking battery from house battery when the motor was turned off, the caravan manufacturer had fitted a VSR ( Voltage Sensing Relay ) type isolator in the caravan.

This was the second faulty part of the install and the cause of the brakes locking up, BUT, this brake failure most likely saved the RR from catching on fire.

Starting with the second faulty installation first.

All the manufacturer's of standard VSR type isolators specifically state that there isolators must be located as close as practical to the CRANKING battery.

The reason for this is that the further you get away from the cranking battery, the greater the voltage drop cab, and if the voltage drop is enough, standard VSR type isolators will oscillate ON-OFF-ON-OFF, and will not charge the auxiliary/house battery.

So as soon as the Range Rover's alternator voltage dropped, the VSR shut down and everything in the caravan was then being powered from the house battery.

Things like the fridge and electric brakes.

Eventually, the house battery was discharged so low that the brake system mistakenly sensed the low voltage as a "Breakaway" situation and applied the brakes.

The end result was that the caravan came to an abrupt halt and then the owner could not move the van as the brakes could not be released. So he had to get a tow truck to take it into Bulahdelah, where it was left for the night while he drove back to Sydney.

While trying to sort out the problem when the brakes first locked up, the owner contacted the LR dealership in Sydney where he bought his RR and where he had the "charge system" installed.

The dealership's response was "These caravan companies should now how Land Rovers advanced electrics work, and make their vans compatible"

That was all the assistance they gave him.

So he then called the caravan manufacturer, who referred him to another Range Rover owner who also had one of their vans.

The Range Rover owner gave him my contact details and the problems began to be resolved.

While the new RR owner travelled back to Sydney for the night, with out his caravan, I contacted Ian at RV Powerstream, a good company I deal with, at Smiths Lake, just 20kms away from the caravan.

He didn't have all the gear required but suggested trying Tuncurry Auto Electrics, another good company I have worked with.

The following day, as the owner was returning north, from Sydney, I phoned him with the suggestion of how he could get his caravan fixed locally, with the only draw back being that he had to drive 60Kms back the opposite way to his home destination.

He was more than happy to go the extra distance, because the problems were going to be fixed a lot sooner than having to wait till the following Monday and then trying to get it sorted.

When Tuncurry A/E got the RR, they found the dealership had used 8 GAUGE ( 8 GAUGE and 8B&S are the same size but 8 GAUGE is used to label a specific cable type and more on this later).

They had used 8 GAUGE cable to connect from the cranking battery's positive ( + ) terminal to a 50 amp circuit breaker then out to the rear, to positive terminal of a 50 amp Anderson plug.

They had run the same 8 GAUGE cable from the negative terminal of the 50 amp Anderson plug, to the negative ( - ) terminal of the cranking battery.

First off, as most people who work on new Land Rovers know, under no circumstances is anything to be wired to the cranking battery's negative terminal, especially high current circuits, because this causes all sorts of battery monitoring errors in new Land Rovers.

As a Land Rover dealer, they should have known this.

Next, the cabling should have been 6B&S cable ( 13.5mm2 ) but they had used 8 GAUGE cabling ( 7.9mm2 ).

For 8B&S cable ( which is also 7.9mm2 ), the maximum current rate of the protection device is 40 amp, not 50 amps, but it gets much worse.

They had not use 8B&S automotive cabling, they had used 8 GAUGE "SPEAKER" cable.

They must have gone to their local electronics store and bought the cable they needed, not knowing it was "SPEAKER" cable and as such must not be used for high current applications.

Automotive cables are designed to have a minimum safe temperature tolerance of 70C, most speaker cable is rated at around 40C.

Automotive cabling is rated at a maximum "CONSTANT" current rate, speaker cable is rated at a maximum "PEAK" current rate.

The maximum current rate for a protective device for 8 GAUGE speaker cable is about 25 amps.

So the dealership had actually installed a fire hazard and the only saving grace was that the caravan manufacture had incorrectly installed a VSR isolator in his caravan, and this had actually disconnected the van from the Range Rover, probably within minutes of the beginning of the trip from north of Brisbane to Sydney.

Had the isolator not shut down, the Range Rover would most likely have caught fire before it had reached the QLD/NSW boarder.

But wait, there's more.

The dealership's "expert" service staff had FORCED the Anderson plug's terminals into the plug, up side down.

If this installation had been done by a COMPETENT person and CORRECTLY, they probably would have charged anywhere between $150 and an absolute maximum of $250 for the parts and work involved.

Not the LR dealership, they charged their good customer $1,000, to fit a fire hazard.

Who's at fault if it all goes wrong?. Pat