Car Batteries and Relocation Kit's Q&A

[thechuckster]

run an earth wire up to the engine and see if that fixes it.

also - check the earths that used to be up the front - there should have been several straps - the largest going to the engine, to the chassis and probably elsewhere. They should have zero ohms between them and the )-) on the battery - if not, then you have to fix.

I vote poor earth continuity.

[petergoudie]

The flat strap which I thought you had can be 25 mm or 12 mm wide and about 3mm thick made from woven wire.

All of these high current wires & cables have a duty cycle. That is, while they give a rating it is for a limited time. You can feel this because they get hot just from their own resistance. If you look in a CIG welding catalogue it will give you a rating taking into account the length of cable and give a duty cycle (ie. how much on & off time)

Also, as they get hotter their resistance goes up.

[LeaThaL]

ah i get ya now peter,

something i just thought about too is will all this affect the alternator charging the battery also? im gunna add some earth straps as youve memtinoed to replace everything i have on there now just to assure their all fine too as their only old material ive had lying around and i wanted to see if they made a massive differece


thanks again for all the info too guys

[mullett]

Someone mentioned before about MX5 batteries: This is a cheap way to get a sealed battery that can be located in the car without an ugly (and huge) battery box. Cheaper than an Odyssey battery, but they have to be upright (unlike Odyssey)

-RM.

[petergoudie]

The resistance won't be so critical with an alternator because the current is lower and for most of the time the alternator is only trickle charging.

[thechuckster]

alternator wont explain the inability to crank the motor - but if remoting the battery and you have charging issues, run a separate sense wire from alternator direct to the battery (doesn't have to be thick wire). The charge lead can go to the starter motor post.

[allencr]

Does it now or has it ever cranked/turned over very fast?? You've written that it does crank at a fast speed - sometimes. If it cranks fast, even once without smoking any wire's insulation, then the battery & cabling are OK and there is a problem with the starter motor and/or solenoid, as long as the ignition switch is OK.

[LeaThaL]

yeah it cranks over really fast when it does get a connection so that seems its fine, i bought a BRAND NEW battery yesterday thats a 600cca and i put it in and it still does the same thing so im guessing it just needs decent earths, anyone know where i can get the wire earths that are like weaven mesh like pete mentioned?

[takai]

i thought it might of been voltage drop from the length and thus why i tryed the 4wd battery.

yes i soldered the ends in using decent ring ends i got from the same place as the wire, and i replaced the positive terminal with a big brass one with a wingnut on it and its all nice and tight, the negitive is one solid piece, this is the pic i have in my members ride thread



and by heavy gauge flat earth straps, you mean the ones about 10ml wide? as i havent used anything like that for an earth, ive used the standard located and issued earths, and then i added 3 or so more using what i think is like 8 or less gage wire with soldered ends sent to the chassis

thanks for all the info so far too folks, REP is with every post

If thats the only power wire (red) from the battery to your engine bay then you are in a world of hurt, its only a 4AWG wire, which while its rated to 120A wont be pumping that much with the current loss over the line. Get a 2AWG line or better.

My race car runs 4AWG to the starter alone and then a separate 4AWG line for the rest of the electrics.

AWG is the gauge of the wire btw.

[MWP]

Running two cables (one for starter and one for everything else) is the best option.
Two 4AWG's as Chris said is the way to go.

Its better due to no voltage extra drop on the everything-else cable during cranking which means easier starting.
Its also easier to route through the car than a single thicker cable.

[takai]

In a road car i would use 2 2AWGs rather than 4AWG, or a 2AWG for the starter and 4AWG for the rest.

[LeaThaL]

ive got that cable and one that i think is like 6gauge, will that do the accessory/fusebox or whatever? if not, ill leave it as this as its getting the car started (im a tightass seeing its still in the back yard) and ill get a decent wire after im needing to depend on it as a daily

thanks for the info too takai and MWP

[MWP]

...and wire directly to the starter and fuse box. Dont use the existing cables.
I found that after doing so, in-car electrics like electric windows and windscreen wipers worked much better

For example, i traced where the ign/acc power cable went from the original battery terminal into the fuse box (photo below).
I removed that cable, then bolted the new 4AWG supply cable to it.

[takai]

ive got that cable and one that i think is like 6gauge, will that do the accessory/fusebox or whatever? if not, ill leave it as this as its getting the car started (im a tightass seeing its still in the back yard) and ill get a decent wire after im needing to depend on it as a daily

thanks for the info too takai and MWP

Um i would be upgrading the cable ASAP, when you are cranking and its pulling power it will be heating up, and if it gets too hot then thats what electrical fires are made from.

[RA35GT]

OMG.

The voltage drop with that cable would be massive when cranking. It may be rated at 250A (re: first post), but thats prolly at like 500mm and for small duty cycles.

I would use do as Takai and MWP suggested. (2 x 4AWG or 4AWG+8AWG)


This is how I wired my car (although my battery is in the front)
2AWG cable straight to starter motor.
4AWG cable to fusebox.
I also use a separate 8AWG cable to the alternator. (and there is another 8AWG cable to other ancilliaries)

(Note: I have a 2AWG earth to the block, a 4AWG earth to the chassis, a 8AWG earth to the head and another 8AWG earth to another part of the chassis)