Thread: Battery relocation

are you aware of the legalities of have the batteries inside the vehicle.....

they need to be in a box which is has a vent/drain pipe to the outside of the vehicle....
incase acid should leak or to vent out the gases........this is more of a safety issue.....

other than that it should be ok.....but you will need some heavy cable for the winch
to have enough power without overheating the wiring......
if drivesafe reads this he will probably know what cable is best.....
i would go for something like #4 guage...which is as thick as the main positive battery cable....
or possibly thicker......

if you plan on using one of the batteries for accessories and wish to have it isolated from the other....
then drivesafe is definitely the man you need to speak to......
he will have exactly what you need for the job.....in a DIY kit.....


now...can i ask why you want to move them from under the bonnet....?

Am aware of the regs for the battery in the back, have been talking to engineer and he says no problem, will be using 2 gel filled batteries in boxes.
70mm2 cable is more that double the size of the standard cable that comes on the winch and has a current rating of around 250amps +.
Was hoping drivesafe has read this
Moving them from under the bonnet to reduce the weight over the front axle due to a big block being there.
Thanks anyway.
Damien

In general the longer the cable, the more voltage drop you get, especially with a high current drawing unit like a winch. Unlike 240volt stuff, the low voltage means the heat load over a cable is fairly big. Use the shortest cable you can is always the best. The negative cable can go straight to the chassis as long as all load drawing devices have good earthing contact to that same chassis.
I am not an auto elec, but heavy equipment mechanic for 30 years.

Hi 6.5rangie, I don’t do much work with winch set ups as most people usually get their dual battery set first and then go and get a winch later.

Having said that, from my understanding, most winch set ups are done with the power for the winch coming from the main battery and always having the motor running while winching.

Is this what you are planning and having the rear batteries as additional power.

If so then the cable you have is heaps big enough but I would strongly recommend that you run an earth cable from the rear batteries to the front of the vehicle.

In most cases you MIGHT get away with using the chassis but the problem is that you have to be 110% sure that you have absolutely no resistance in the chassis, caused by paint, rust or any number of other things that may cause any form of resistance. Note, there is NO effective way to determine if the is a resistive point in the chassis without actually applying a large load, for a long period of time and see if you get a voltage drop. Not realistic.

Winch operations can some times mean using the winch continually for long periods of time. With the high currents needed while using a winch, if there is the slightest resistive spot anywhere in the chassis, you are not only going to get one hell of a voltage drop but you are going to get a hot spot, that in a worst case situation, could cause a fire.

Play it safe and install a negative cable.

Drivesafe, I will only have batteries in the rear and none in the front to reduce the weight over the front wheels. Also i need to know if the cable say running to the winch or accessories can also be used to charge to batteries aswell (whilst not using the winch it is charging the batteries) or do i run another cable just for charging.
Damien

You need to run a cable from Battery to Starter motor.
So run from Alternator to Starter fitting (like streeters with Rear Batteries do)

Then run a new pair of cables (+ve -ve) from the rear to the winch.

Cheers
Mike

You could do it as TombRaider posted but to assist in getting as much power from the alternator while using the winch, I would run the heaviest cable you can get your hands on and run the positive from the batteries to the alternator and from the same connection point on the alternator to the winch.

Remember that you need to have the negative coming from both the batteries and the winch, grounded as close to the alternator as possible.

Running thick cable is a big job but if you have the time, try to get the most direct route so the cable is as short as possible, to reduce voltage drop, particularly while winching.

I have 70mm2 versolfex xlpe, its like welding cable (worth about $1800 for 100metres), and was thinking of using 2 busbar systems in the engine bay for both batteries to branch off for everything that is needed.
Damien