Moving Battery to the boot - what gauge wire?

[Dutch24V 0]

Hi all,

 

I've just aquired an Optima Yellow top and need to mount it in the boot. I'm thinking of using 0-AWG wire. Is this thick enough?

 

Roughly what sort of ampage is the starter motor going to draw through this wire as I want to fuse it both ends, but not sure what size fuses to use?

 

Thanks,

Dutch

[LJ 0]

Bump, as also interested.

[Dutch24V 0]

I've been speaking to an auto electrical shop over here today and I'm going to use 5 metres of 35mm

[Go-rado 0]

Unless you have a supplier in mind, you might want to try these guys: www.vehicleproducts.co.uk

 

They do battery/starter cable by the metre in black or red. 40mm[sup:28ku6g04]2[/sup:28ku6g04] with an O/D of 11.8mm is good for 300 amps, and costs £5.84/m + VAT and delivery (£3.95 for UK orders less than £100). They can supply lots of other very useful stuff too!

 

Lee

[Dutch24V 0]

Thanks for the link go-rado. I already have most of what I need, but that looks like a really handy site for some other bits I need to get :)

[steveo29 0]

beemers often have boot /rear mounted batterys ....have a look at a few and rob its cable it will have a nice oem terminal on and save you using one of them aweful gold plated pieces of crap

[Kevin Bacon 5]

My battery is boot mounted and yep, 0 AWG is perfect. I get 14.3V at the ECU, which is at the front of the car, so Voltage drop is negligable.

 

I use 300A fuses at both ends. The starter will draw anything from 40 to 100> amps depending on temperature.

 

The fuses are just for protection in case of a short to ground, but I hate grommets, they're sh1te. They're not man enough to hold 0 gauge. Use compression glands instead mate. B&Q sell the right size ones for Corrado bulkhead holes :wink:

[pyro3911 0]

I am also looking at this mod as I am going turbo. :D I find it is always easier to pick the brains of someone who has done this already.

 

where have you routed the cable from the boot. I assume it is down one side of the interior of the car then through the firewall. Also is it best to earth the battery in the boot or run a second cable back to the front of the car.

 

Is there any other safety points to consider when doing this mod.

 

thanks ian

[Dutch24V 0]

Cheers Kev. I'm actually runnig 2AWG (35mm

[Philuk 0]

2AWG will probably do it but 0AWG is just much more on the safe side, dont want the cable going all drippy when you are pottering about now! or when your firing it up!

[dinkus 10]

I'd personally go with 0AWG, but if you have a Google about there are charts that list what gauges are good for what DC loads.

 

If you run the cable down the passenger side of the car, there is actually a hole in the bulkhead that was there for the AC pipework, which should be just about the right size.

[gsbellew 0]

We run a new battery cable the length of our Limo's from the battery in the boot to the front, we use 50 square cable (50mm2), any electrical wholesaler should have it, 50 square panel wire is what they seem to normally call it.

[dinkus 10]

For those of the slightly confused disposition of how to convert between AWG to mm[sup:3tu09p8u]2[/sup:3tu09p8u], there's a little calculator and chart here - http://www.reuk.co.uk/AWG-to-Square-mm- ... verter.htm

 

FYI 50mm[sup:3tu09p8u]2[/sup:3tu09p8u] is near as dammit, 0AWG 8)

[Dutch24V 0]

I've found this site: http://www.powerstream.com/Wire_Size.htm

 

It has 2 current ratings, one "Maximum amps for chassis wiring" and the other "Maximum amps for power transmission"

Err, which one should I be looking at?

 

Also just found this: http://www.motorcityreman.com/technical-info.html

Maybe I need 0 AWG as you say? Damn! I have 160A fuses either end so do you think 2 AWG will really be ok?

It'll only have to carry the max current whilst starting though and the starter won't ever draw more than 150A will it?

 

Dutch

[dinkus 10]

If you use wire that's too thin, it'll get hot, conduct less well and possibly catch fire. However, as you've got fuses at each end that will pop long before the wire even gets hot, let alone catches fire, you should be fine. Especially as you only really need mega current for a few seconds while cranking the engine over.

 

The only real risk is that you pop the fuses when you go to crank the engine over on a cold morning, but you can always wire it up outside the car first to see if it works...

[pyro3911 0]

The insulation on wire will not burn even if it subjected to a massive load. It melts and smoulders but thats when the problems start as the heat involved can then heat surrounding materials which will cause a fire.

ian