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What is the intention of this rule??

In the event of a miss-hap, there is to be a switch that cuts the power to the engine and ancillaries to prevent a potential fire or such like??

I imagine the vision was to put a isolation switch into one of the main battery cables to break the circut right??

Why do it that way???

Why not bring it in line with the rest of the motor sport standads in NZ, such as the spec's for circut cars, rally cars, trials trucks etc etc.

They require a kill switch.

The kill switch cuts power to everything, ingnition, fuel pump, ecu, absolutely everything.

The battery circuit remains, i.e main power to starter, main earth to engine block.

The reason I am querying this, is because in vehicle's such as mine, which is a very simple set up, where I have chosen to run dual batteries in parallel, with the engine and the winch running of the them both, a battery isolation switch doesn't really work.

Firstly you need to find a isolation switch capable of handling the current drawn by the winch, 700amp is the max drawn by my Runva from memory. I can't even find one rated to that.

Then there is the extra battery cable required. Obviously we are trying to run the heaviest cable we can get our hands on, so running monster battery cable into the cab, into a place where both driver and co driver can get to it is an issue, let alone finding a spot for the super sized 700Amp isolation switch.

I don't see the point of doing that.

Especially if the intention of the rule is what i suspect it is.

The intention can be met through another method that is far simpler.

If its good enough for all the on road motorsport factions, its certainly good enough for us!!!!!!!!

Infact its even more relevant for us, as it means we don't compromise the principles of good electric winch set up.

I don't understand what you are querying? The rule is quite simple and is worded as it is (a copy of the Oz rule) due to having to deal with electric winches and the loads they draw. I'm not sure what you want to do that is different and we are talking about a kill switch.

FYI a switch that can handle the loads required for your winch will cost about $50 from any good marine store. They are rated about 275amps continous (60 min), 600amps intermintent (5 min) and 1200amps surge (30 seconds). Also a 4.6hp 12v motor draws about 450amps.

I think it should cut the power to every thing and 2500amp isolaters are not that big or hard to wire. There are lots of options just go to a heavy repair work shop that deals with bush or digger equipment. When you have a winch jam on you will see what can happen to the front of your truck.

Theres a Hella switch available off the shelf that will take those current loads, I think Klem runs one, we definitely run one, we run every thing through it - including the electric winch, and when its off the whole truck is dead

Quote Darin Neeley:

I'm not sure what you want to do that is different and we are talking about a kill switch.

The rule says:

"....a mechanical battery isolation switch for the batteries that provide power for the engine, ignition and fuel pump..."

You can do that by putting a battery isolator switch into the heavy negative cable of the battery circuit, as i imagine was the intention correct??

That is a battery isolator.

A kill switch, by definition in motor sport is different.

A kill switch breaks the circuit to fuel the pump, fan's, ignition, lights absolutely everything.

It means you achieve the same out come as the intention of the rule, but you can leave your heavy battery loom in one piece.

Thats how 99% of the competition vehicles in the world are wired.

Just to make my point a bit clearer, the motorsport NZ rule can be found at the link below, on page 19, rule 5.2:

http://www.motorsport.org.nz/Pdf/LiveMM34%20Book1%20App2%20Sch%20A.pdf

It says:

Circuit breaker: All vehicles shall be fitted with a spark proof ignition switch/circuit breaker that is positioned with in easy reach of the driver and co-drover while in their normally seated position (harness's worn), capable of breaking all circuits that keep the engine running i.e ignition, fuel pump, alternator etc etc

According to the 4x4 challenge's rule's, the intention is the same as the above, but as usual we go about it the hard way???

Obviously my trucks set up with the circuit breaker, as thats whats required for Trials. It kills everything. Nothing works, no lights, no starter, no nothing, absolutly nothing. Its a pain because I have to keep resetting the clock

So what advantage to you guy's see in running your battery isolator??

I don't get it

[Modified by: Peter Hall on November 17, 2009 08:26 AM]

Have you seen what happens when an 800amp cable is shorted or a winch solenoid welds it's self closed? We run more battery power than any other motorsport and that causes diferent safety issues.
There was a huge amount of discussion around this at the time it was introduced and due to electric winches (and the complication they cause) we copied the closed comparable rule. (being the CCDA rule ie Oz winch challenge)

I still firmly believe that all electircs should able to be isolated including winches. I agree a kill switch that disables the vehicle as Peter has descrided is required BUT we need to go further as well.