Lone Wolf replied:

No need for smartarse comments. :-)

Bugger!!

Anyway, a friend of mine has had exactly that done to his Nissan.

Apparently, Grant, from Cross Country 4 x 4 in Adelaide put a kit in like you ask for.

They are on the web, so you may be able to email him.

Cheers

Wolfie

David Au replied:

Tony it would have to be done by an auto electrician.
You would require major rewiring.
No you cannot buy a kit.
You could do it using a Redarc battery isolator quite easily, but the re-wiring of the vehicle is the major issue.
Install a low voltage cutout so if something is left on it will disconnect the accessory circuit. That would also need to be done by an auto electrician. Tampering and modifying modern vehicle wiring is not straight forward.

Utemad replied:

I have done exactly that. I only used two relays and a switch.

Firstly I put my Second battery in the Starting battery tray. Then I put my Starting battery in the Second battery tray. Then I connected the Second battery as if it was the Starting battery. Then I connected the +ve of the Starting battery to the starter motor +ve stud. I then connected the -ve of the Starting battery through the relays in parallel to the engine and the body. I then switched the relay through a switch on the dash which is powered by an 'ON' wire.

This allows me to have the entire car running from the Second battery when the key is either off or accessory. When I start the car it starts from both batteries. When the car is running I can switch the Starting battery out of the circuit so the Second battery charges faster.

I use two Starting type batteries now however my Second battery used to be a Deep Cycle and the system worked just as well.

Keep in mind that this system starts off both batteries so you're not supposed to start from a Deep Cycle battery however I had no trouble with longevity when I did it. I think that might be because I wasn't starting only from the Deep Cycle as both batteries were connected in parallel during starting and I only have a 2.6L petrol motor (might be different for a diesel etc). I worked out a remedy to this that would require one more relay to cut the Second battery out of the circuit when cranking which would protect a Deep Cycle battery but never built it as I went to two Starting batteries instead.

The problems I have with this is that if I leave my lights on and flatten the Second battery then my fridge stops. Th alarm is also currently set to my Second battery as I installed it prior to this battery setup. However my alarm has a backup battery so it's not a problem at present however I will rewire the alarm one day......perhaps.

Another option is to have a momentary switch to energise the relay coil which is powered off the Main battery so that if your Second battery is completely flat all you have to do is push the momentary button and then start the car. I haven't done this yet and probably won't.

I have also been warned to put a surface charge into the Second battery before I flick the Main battery isolation switch otherwise I could spike the electronics. I have never had this problem but it is something to keep in mind.

Hope this is the info you're after.

Mad Dog (Victoria) replied:

If it's just the headlights you're worried about how about fitting an alarm. Jaycar have a kit for $23.95.

jaycar kc-5317

Member - Chrispy (NSW) replied:

I've put the Prianha DB150S into both of my cars. Fairly cheap if you do it yourself. Doesn'y cater for the accessories (i.e. standard car accessories such as radio, lights, etc) running off the aux, but even if the main dies overnight (leaving the radio running full bore with the headlights turned on for example) than simply connect the second battery's positive to the starting battery's positive and away you go - an internal jump start.

There are cheaper equivalents around to the Piranha - but I've found them to be completely reliable and at the end of the day not all that expensive anyway.

There are basically three schools of thought on this issue - Piranha electronic, RedArc and simple switch with a big diode.

Your choice - I just prefer the Piranha for ease if installation (4 wires - large wire to aux pos., large wire to start pos, ground and a permanent 12v supply (spade connector of the wiper motor's terminal).

GO_OFFROAD replied:

Have had a high failure rate of the Pirahna boxes, including 3 on my own car, but I run an isolator to seperate and charge the batteries as required, while running a silver contact solonoid which links the batteries when the winch motor has power, so the big current draw isnt running through the little electronic box.

A good manual isolator is available at your local Cat earthmoving store, which has a steel key and is rated at 500 amp for about $120.

TonyH replied:

Thank you all very much.
Thought I'd been fed a red herring, was told that Rotronics system works on this principle. Their website doesn't back that up. Mis-informed salesman or bullcrap artist.
The Pirahna system I have not ruled out, nor any other.

And not a single smartalec comment or bitch fight :-)

Wolfie- a name would be appreciated

Thanks again

Tony Harding

Member - Jeff M (WA) replied:

$135 for an Arrid Smart relay from The 12 Vold Shop, buy and Auxilery Fuse box, run all your devices like CB Radio, GPS, Fridge Sockets, blah blah blah from that, Stereo and Internal Lights can be rigged up my removing the fuse for "DOME" under the bonnet and plugging a Spade Crip connector into the side that goes to the accessories, then running that back to you new Aux fuse box. Then the car starts off the start battery, headlights run off the start battery, pretty much everything else runs of your aux and it's all automatic.

That's how mine works...