I am wanting to relocate the battery to the boot so I can fit my fuel swirl pot and Bosch external pump in the engine bay. Has anyone done this and if so what size cable did you use?

 

Just as an option, you could relocate the washer bottle instead: that's what I did.

But, to answer your question, I would use 25mm2 cable. There are battery relocation kits available that have all the parts you need.

 

Cheers Tim, was thinking 170 amp cable would be enough, may move the washer bottle aswell as could mount the pump in that area.

 

25mm/170A cable means you're unlikely to drop more than 0.5V during cranking.

Make sure earth connection is really good to the chassis, and that the battery is securely mounted and installed safely so anything thrown in the boot won't short it out!

 

Use the best cable you can get, and think about using an earth return cable too, maybe along the opposite cill?

 

Shouldn't need an earth return cable - the chassis will have a lower resistance than a cable, so just make sure the battery earth is well connected to the chassis in the boot.

 

beg to disagree.

earthing kits are well worth having fpor older Scoobs, and any return path will be dependent on making a GOOD connection. You can do that easily with a cable, not so easily to painted sheet metal.

 

Each to their own - if it were me, I'd sort the earthing out so that all the earthing points work right; but a cable back to the boot is maybe easier!

All the cars I've worked on with relocated batteries have not needed an earth cable running from the front to the back - but they tend to be stripped out race/track cars and perhaps don't have the same power demands (no luxuries lol).

 

Cheers guys, work as an electrician and spent 10 years of my military career working on various vehicle categories so won't be an issue. Pity I did not keep a pair of jump leads I once made up they were fit for trucks so would have saved me buying cable. Had a quick look today but I might be leaving the battery in the engine bay as the swirl pot might be too tall for the front but will check and also check on the washer bottle position as also mentioned

 

Is yours a newage? I had a swirl pot made up that took an 044 and fitted where the washer bottle went.

 

Yes mines a bug. Bought the swirl pot 4 years ago so not really rushed to fit it (LOL).

 

Swirl pot is best in boot for safety.
Leave battery where it is,(or move to boot also in a sealed box) if anything reduce size for weight reduction.

 

This wasn't mine (I copied it lol) but gives you an idea:

 

Not sure I agree? Unless you fit a firewall.

Engine bay is designed to cope with crashes and fuel leakage, and the front bulkhead is a good fire barrier.

If you have a rear end shunt with a boot mounted swirl pot it will spill fuel everywhere and with no firewall, I wouldn't want to be in that!

 

I agree with you Tim.

Someone mentioned on a thread previously about a fire risk with fuel and exhaust manifolds.

Neat fuel in large quantities will not burn on an exhaust manifold. I had a burst fuel pipe ln my scoob and it dumped nearly half a tank of fuel on the manifolds. It just evaporated and smelt a bit funny....

I wouldnt have a swirl pot in the boot without the fire wall etc

 

Same thing happened to me.
I remember switching off and watching fuel boil off the down pipe, waiting the huge "wooof" and flames...but they never came.

 

If you want to save money on cable, look for 5/7 Series BMW's in scrap yards/breakers. They have rear mounted batteries and use 0AWG IIRC.

 

The chassis will have lower resistance than a cable due to the CSA of a chassis been enormous compared to any cable and parallel paths etc.

The reason earthing kits work on older cars is due to poorly maintained cruddy connections. You clean those connections it will do the same thing.

Sheilding the sensor cables are where the gains would come from

 

Obviously yes.

 

My setup was done by previous owner,

 

mines got battery under bonnet, swirl pot and twin pumps in boot, quite happy where they are but each to their own

 

You are assuming a chassis in decent nick, not much rust and the joints well made, though.

A high quality new copper cable will be superior, trust me.

 

Purely out of interest, roughly what was the cross-sectional area of the cables?

How thick was each individual strand of copper?

 

Made them over 10 years ago and got rid of them can't remember.

 

Get an insulation boot on that +ve terminal before there's a major mishap, please!

 

Nothing ever in the boot to have an mishap with,

Those kind of accidents help kill off stupidity anyhow.