Printable View
ive heard that doing this can be slightly dodge for some reason, cant remember what was said, be it earthing or the length of the cable.
anyone thats done this allready, can you get a good enough earth from the body in the wheel well, or is it best to extend the earth from the bay ?
the body is the body, doesnt matter where you attatch it to just make sure it is a good connection. as for the power cable, this can be dodgy if you dont use big enough cable. ive seen a guide before, ill try and find it for you
It can be dodgy if your cable is allowed to move or rub through the insulation. Done properly its not dodgy at all.
decent cable and fitting is the answer.
Just a simple bit of advice.... Dont bodge it.
I'd drill a hole in the wheel well and weld a nut or a bolt to it to ensure getting a good, solid earth point myself. Also unless its a gel type battery like an Optima (specialist ICE battery), it will need to be in a battery box and have a breather tube connected that vents outside of the car, just incase there's a hydrogen build up (remember making hydrogen go pop in a test tube at school? don't want that happening in a car!). Positive cable will need to be fairly heavy duty stuff, consider 4Ga the minimum, 2Ga would be a good idea.
whats wrong with the back bumper bolt as an earth point??? its what i always use
Get a pair of cheap as chips 3meter jump leads of eBay for £10, instant neg & pos battery cable :thumb: remove the jaws and your onto a winner. As for a hydrogen breather tube, waste of time IMO.
I did mine thus:
http://i34.photobucket.com/albums/d1...P1030759-1.jpg
Neg/Earth Bloted through floor pan with large washer contacting bare metal around the hole for max surface area contact and then painted to seal against rust.
I put mine here for weight balance (more to the rear and left)
As advised, best go for quality cable:
http://www.vehicle-wiring-products.e...tterycable.php
Ref: 315 will be thick enough. I used this in conjunction with appropriate sized convoluted tubing they also sell just to be safe (and a shiney black hose is a preference over ugly red cable :-)
cheers for the info lads :thumb:
i think ill combine all your answers with a setup ive got in mind
do you think these 400 jumpers will do for the job ? the proper 300w cables nearly £6 a metre.
http://cgi.ebay.co.uk/400-AMP-BOOSTE...3286.m14.l1318
" Each copper cable is 2.5 metres long and has a solid brass core for long life "
i would do it the proper way, just cant afford it, but if these arent safe. ill steer clear till i can.
any jump lead suitable for a car will do it :thumb:
i was havvin a lil look thru that path, and most of the jumpers i saw were 170-ish amp, some 250/300 and those are supposedly 400, the composition of the cables internally are probably different as designed for different purposes, but in theory the 400's should be cool, but dunno, might be risky cos they were never designed to be in constant use like proper cable, hmmmm...
ive got access to some 0:GA cable, but its nearly as thick as a penny piece, and weighs a fkin ton.
8:GA too, but its probably not upto the job
somebody out there give me 4 metres of proper stuff for free lol oh .. and a set of battery terminals too lol
just stroll into your local friendly tractor or truck spares place & ask for the length you need. jump cables are badly made & they get way too hot.
yeh decided to do it proper now - got a friend of mine looking into some cable for me, he does hefty sound system installs and knows his **** about cables, if im lucky he'll get me some for free, if not prety cheap.
ive had a lot of experience with relocating/adding batterys here there and everywhere.dont look at specialist sound system cbaling,its far to expensive for what is esentially a job that doesnt need it.look for welding cable,many (and blackjack will back me up) people who compete in the spl leagues run a silly amount of batterys and a lot cant afford to buy 50+ meters of 0awg cabling so they use welding cable,you can get vairous sizes and youl find somehting suitable and cheap. hope this helps
by welding cable i assume you mean the earth leads?Quote:
Originally Posted by blackpoolbouncer
Or just go to any scrap yard with a BMW in it and get the power lead they use to locate there battery in the boot, you also get a nice + post for under the bonnet, looks nice and factory.
i have heard that running the engine earths in the engine bay and allowing it to earth all the way to the rear of the car purely through the body is bad.
it allows the tiny electrical currents to react all over the body of the car and help promote rusting. think is a reaction with the small currents and the damp and the metal probably has a scientific name but i dunno what it is this was discovered on the old minis which is why some people choose to run the earth cable all the way back to the battery terminal.
this might be a load of rubbish tho, but if you think about earth points on cars they are usually corroded and rusty! there may be truth in it
Best idea :thumb:Quote:
Originally Posted by Ben
-------------------Quote:
Originally Posted by a2lt16v
yeh i agree with that, i was told by an engineering teacher a few years back, its not such a good idea to run the earth that far back, tis why i mentioned it in the first post, he didnt so much say on the lines of what u just said, but i wouldnt be surprised if that happened, he did say something about the time it takes for the current to flow thru the body and back to the front end for proper earthing, plus electrical interference on the way. probably why they put the battery so close to the engine with such a short lead to the body, saying that most bmw's run it way back tho dont they, interesting discussion on the matter tho. depending on how much cable i can get my hands on, ill either use one of the rear seatbelt mounts as the earth or run it back to the proper earth point in the bay, going to gain a little weight with the extra cable, but it might be worth while if its gonna cause running probs or possible 'extra-terrestrial' rust lol