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Battery in BOOT?


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#26 SmacT

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Posted 24 November 2013 - 06:47 AM

Cool, I was just thinking smaller cable to the starter may make it easier to fit past the headers etc.

Thanks.

#27 Rockoz

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Posted 24 November 2013 - 10:51 AM

Not too sure about the bulkhead connector.

I personally would be running the main cable under the floor.

If you use a bulkhead connector as linked previously, you will have live power both sides of the bulkhead.

May be OK if you need it.

But it is also another connection that can loosen and cause problems.

You would also need insulation boots to cover the exposed ends otherwise you may end up inadvertently causing a short.

I would run the big stuff down under the floor to near the starter, then using crimplinks and good heatshrink, ie the stuff with the glue inside, drop down to a short run of smaller more flexible cable to the starter terminal. Then fusible link fromm there to feed to the fuse box.



#28 _jtfenech_

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Posted 24 November 2013 - 12:56 PM

whats the difference between a fusible link and a fuse why not just run a fuse



#29 Toranamat69

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Posted 24 November 2013 - 02:34 PM

Fuses are big ugly looking things that take up a lot of room generally but you can use them.  There may be a difference in their short time overload capacity but 12V car stuff seems pretty skint on any data to compare.

 

This is what I had in mind for a main battery cable CB - I see they now do 300A. Would definately be better than having an unprotected large welding cable regardless of where they are run. 

I will just have to try one to see if the starter inrush will trip it for my high torque starter as again, seems they don't like to advertise the trip current characteristics.

http://www.ebay.com....6#ht_426wt_1161

 

http://www.ebay.com....#ht_1692wt_1161



#30 Rockoz

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Posted 24 November 2013 - 03:21 PM

Wont handle start current.

As it says its for accessories like audio and inverters.

A fuse will protect a circuit against overload or short circuit.

Have a look at the size of the fuse wire in relation to the wire size it protects. Huge difference.

The fusible link however is generally not a lot smaller than the wire it protects.

Its like a fallback if you get a major short in the wiring, in particular the wire that feeds the fuse box.

Its ultimate aim is to blow hopefully before your harness catches fire in an extreme short situation.

 

Electrical for Dummies.

 

Rule 1.

Regardless of the truth, all electrical items are filled with smoke.

If you let the smoke out of the component it is stuffed.

 

Rule 2.

You cant recharge electrical items with new smoke. The smoke is put in at the factory by special secret processes.

The parts that lost their smoke will need replacing.

 

Rule 3.

Some items will only loose some of their smoke, However even if these items continue to function, they will eventually loose their smoke.

 

Rule 4.

All electrical items will loose their smoke at an inconvenient time.


Edited by Rockoz, 24 November 2013 - 03:22 PM.


#31 Rockoz

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Posted 24 November 2013 - 03:29 PM

Oh. And as for the breaker on the battery. Your starter has the potential to pull peak power of 1000amps or so.



#32 Toranamat69

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Posted 24 November 2013 - 07:51 PM

Yeah I know the inrush is large but they don't tell you what inrush those CBs will take.  All the CBs we use on power systems have a current curve which means they will take a huge inrush for a short period and not trip with a decaying time dependant on current.  My high torque starter pulls about 80 amps when cranking.

 

Being that I have no idea how these DC ones actually work inside and info seems limited, I'll try one and let you know.  $25 is not exactly risking cattle stations.

 

I had a feeling that was the difference for a fusible linkas they don't often actually blow.  I kept my mout shut though as I wasn't that confident but I tend to agree they are designed to take a lot more current for a lot longer before they let go than fuses.



#33 Toranamat69

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Posted 24 November 2013 - 08:27 PM

This one still doesn't give the complete trip curve but starting to give a little more useful data such as max break current and states that it does have a delay curve for motor starting.

 

http://www.newmarevp...t_Breakers.html

 

I suspect these will all work on a similar thermal trip sensing so they will have an inverse current - time curve bult in - would be great if they advised it so you could properly size the breaker to your application - there is a lot more to it than saying it needs to be able to cut out at 200A or the likes.



#34 _hutch_

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Posted 24 November 2013 - 08:46 PM

I'm not a great fan of batteries in the boot,but if your going to do it you will need to use proper automotive cable 000 cable will be fine,i generally run the cable through split conduit and tape it as well,i clip it with rubber covered "P" clips.I have seen ppl using that orange cable and it will eventually break off due to vibration,as far as an earth I run an earth from the engine to the body and then one from the body to the battery obviously

#35 Marks LXTorana

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Posted 26 November 2013 - 07:53 AM

Wow, amazing what can happen when you resurrect a thread from the past! All interesting reading but I think the general consensus is that a fuseable link on the battery cable is not a common or expected safety feature.

 

I invested in a $2 grommet and with the relocated cabling I am comfortable it is not in any threat of causing a fire. Incredibly, since relocating the battery cable lower down the firewall and putting a new spade on the starter wire, the cranking speed/power seems to having doubled. Previously if the engine was warm it was lucky to turn over (sounded like a flat battery) although it now turns the engine over like there is no compression!!

 

 

 

Hey everyone (anyone)!

I currently have a boot battery set up and I have recently relocated the live cable through the front firewall as it was close to rubbing through the insulation and shorting out, which made me wonder - in all the posts and threads regarding the battery relocation to the boot, no-one has mentioned the use of a fusable link? I hate to think of what might happen if the live battery cable is directly shorted to the chassis, under the front carpet or in the engine bay!

Being a V8 with extractors there is not a lot of clearance to work with, although there needs to be enough movement in the cable to allow for the engine movement under power/deceleration. Hopefully with a grommet installed I do not need to worry although always best to expect the unexpected.

 

Has anyone considered this or done something that i can replicate?

Cheers.


Edited by Marks LXTorana, 26 November 2013 - 07:55 AM.


#36 hanra

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Posted 26 November 2013 - 08:46 AM

Interesting reading that the laws require batteries in boots to be vented. I guess they didn't think about that in the 60s when lead acid batteries were standard fitment to the boot of Mini's. Anywho....

I wired my mates Monaro and relocated the battery to a box in the boot. I've run his through a battery isolation switch accessible from the rear exterior underside of the car, the alternator also runs directly back to the battery in the boot. If he does have an issue either himself or someone externally can flick the isolation switch to kill all power to the car including power generated by the alternator. Runs a BBC with hi torque starter so don't think much on the market in terms of CBs or links would handle the starter current.




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