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starter battery in the back of an FJ40

Posted: Sat Aug 07, 2004 4:06 pm
by Fieldsy
I just about have my 308 into FJ40 converson done but I have run into a problem with my starter battery. We had to get rid of the orignal mount so the battery needs a new home. I am thinking it might be a good idea to put it in the back but I am unsure about the cable I need and will the battery I have be big enough to crank the motor with 4m of cable and an iso switch betwen it and the starter. The battery is a SN70Z Super cheep jobie. will 8mm cable be big enough? What about useing the cable from a set of 500amp jumper leads? ($60) from Super cheep.

Posted: Sat Aug 07, 2004 4:16 pm
by pcman
get a length of 4or 2 guage power cable or for the power run the jumper leads wont be powerfull enough ever tried to use a set of jumperleads with a completly flat battery it wont just start straight away

cheers
pcman

fj40

Posted: Sat Aug 07, 2004 8:49 pm
by Mechman
i had the battery in the back when i brought my tonk. i didnt like it there asit was a PITA taking up space like that. it had a cable about 12mm dia, and although it worked fine, i went and brought an Orbital deep cycle starting battery from ARB thats a sealed unit, uses lead coils instead of plates.. and is about 2/3's the size of the old one with more cranking power.

im running a 253 which is the same size as your 308. i made a simple frame to mount the battery in the space where the heater was... simple.. no long leads.. and no stupid battery in the stupid back.

can post pics if you are interested...

cheers

Posted: Sat Aug 07, 2004 9:59 pm
by Fieldsy
I have seen that done but I am moveing to vic at the end of next year and don't want to give up my heater. and room in the back is not an issue because I don't use the back for anything anyway.

I spoke to one of my sponsors tonight and I scored the cable so it's all good now but thanks anyway

Posted: Sun Aug 08, 2004 10:17 am
by the_smoo
dont go cheap on the cable.. this is the current waveform for a 4 cylinder car at startup!

http://www.picotech.com/auto/waveforms/ ... etrol.html

Posted: Sun Aug 08, 2004 12:25 pm
by Fieldsy
:shock: is that saying it is drawing 420 amps right at the start?

BTW until I read this I had never even herd of a waveform so thanks for edumakateing me :D But seriously thats a lot of power and for a 4cyl

Posted: Sun Aug 08, 2004 12:56 pm
by the_smoo
Yeah..

but its only for a brief period of time, so provided the cable is rated appropriately, its not too much dramas...

explains why jumper cables get farken hot when you are trying to get a POS started.

Posted: Mon Aug 09, 2004 12:15 pm
by ORSM45
i hate voltage drop. thats why i ran 120mm2 mains cable. bit of overkill but it was free, and later i want a winch.

id use minimum of 35mm2 (2 guage) to run the battery in the back.