Battery relocation

Certainly no thinner than the current(!) wire and preferably a size or two up to keep the voltage drop low.

Properly crimped terminals are important too.

A

From

you can get a rough idea of what cold cranking amps would be required (1 cc = 0.0610237441 cubic inch)I'd go for the 40mmSQ from as it should be suffucient.VWP may also be able to crimp the ends if you tell them the exact length and crimps you need, if they don't then you'll need to find someone with a heavy duty crimper. Don't forget you're going to need a big fuse or circuit breaker as close to the battery +ve terminal as you can get it. All the parts you need can be got from , used them several times and not had any problems with them.

But isn't an engine that size going to need well over 200 cold cranking amps?

15mm² is only good for 105 Amps before you even take the extra length into account.

For current wires we use 10 A/ mm² as a rule of thumb but that's only when the current goes continously through the wire. Obviously a starter cable transmits only significant current while starting.

I have never had problems with 15mm² and when I converted a Porsche 928 to trackcar I found that Porsche also used 15mm² wire (about 4 m long) to relate the battery in the boot to the startermotor. The 928-engine is 5.0l V8 and the way that wire goes is anything but straight or without sharp corners so I guess

15mm² is adequat.

Copper being heavy (and expensif) I used 15mm² alu-wire (be it somewhat straighter and shorter than the Porsche choosen route) without problems.

Tom De Moor

Welding cables. Tick, will handle big currents, but more flexible than the normal "heavy jump lead" type cables that can be a PITA to bend arround tight places.

Maybe take one out of an Alfa 164 V6?

Maybe take one out of an Alfa 164 V6?

That's a thought. Battery in the boot on the XJ40 and some Mercs IIRC.

That works out okay upto 6mm², from then on your going to be further and further out the larger the cable gets. By the time you get to 120mm² (obviously not in a car) you'll be putting 1200Amps through a cable rated at only 400Amps.

Ah just use what ever you have laying about, if it catches fire then it's just like the XC90.