PhoenixCapri
West Midlands
Posts: 2,684
Club RR Member Number: 91
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Sept 14, 2010 13:27:20 GMT
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Welding cable works very well and is cheap, though I did once do it with some top spec halfords jump cables without a problem and they didn't get hot. It really is all down to the quality of wire. BMW cable is a nice idea, but for the hassle of getting the damn thing out without chopping it, I wouldn't bother. Terminals are cheap enough and easy to solder on with a blow torch.
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Sept 14, 2010 13:37:45 GMT
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Several things to consider - firstly, the cable from the battery to the point at which the "thickish" (I'm supposing starter, alternator et al.) wires bolt onto it must be capable of supplying current equivalent to all of the cables attached to it plus an extra amount determined by the resistance added due to cable length from the boot to the engine bay. Specification for resistance per foot of a given wire gauge is easily available on t'interwebz with minimal google-fu. Circuit breakers are not required... just fuse everything appropriately and fit the battery in a fibreglass box bolted to the boot floor to prevent the possiblity of it bouncing around and hitting the bodywork. Venting any gasses from the battery needs to be looked into. The advice mentioned above is, as far as I have bothered to think about it... completely incorrect... you want a nice thick cable... a cable that is too thick (there is no such thing) will not increase resistance. The plain and simple method is as already mentioned... steal an existing system from a bmw or similar as this will easily be the cheapest, and you will get a proper engine bay battery connector. Best of luck, any other questions and I'll be happy to help. He's right, i got it the wrong way round, trying to do two things at once here, you still don't want to go overboard on wire thickness though as long as its capable of carrying the current you need plus a bit of a safety margin so that the circuit breaker or fuse (i prefer circuit breakers, they are easier to live with, a blown fuse is more of a pain to sort out than just clicking a switch on a cold and rainy night.) will blow before the wire melts. I used to run 60 amp fuses on my ICE and swopped over to circuit breakers when i had the chance, had one each end of the cable, not needed really but made me feel better and i have had one car burnt out by an electrical fire in the boot and one completely standard car that caught fire under the dash on its stock wiring. :S
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Volvo back as my main squeeze, more boost and some interior goodies on the way.
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Sept 14, 2010 15:33:51 GMT
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if you fancy a trip to shrewsbury, i'v got some aircraft remote starter cable which I used on my fiat, but it weighs a bomb
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Last Edit: Sept 14, 2010 20:27:20 GMT by claymore
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Sept 14, 2010 15:53:40 GMT
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Cheers claymore its a bit of a trek though!
So guys, what rating welding cable do I need to plump for? 350 amp welding cable?....
Thanks for the patience and advice guys
Dave
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Sept 14, 2010 16:06:48 GMT
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More like 250 amp - you'll be pulling the full current of the starter motor through that wire. Look at the Cold Cranking amps of your battery, and make the cable a similar, or higher, rating to that. You want a cable that is at least as thick as the total of the cables running to each battery terminal - preferably thicker, so that the resistance doesn't cause too much voltage drop, which might lead to difficult starting. Vehicle wiring products is expensive, but this page will give you an idea of the size that you're looking for: www.vehicle-wiring-products.eu/VWP-onlinestore/cable/batterycable.phpFor a 2.0 engine, I'd be looking at 150-200 amps as a minimum.
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Sept 14, 2010 18:47:53 GMT
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I got some great long heavy duty cables from a truck in the scrappy, there's a boat load of the stuff on them.
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Last Edit: Sept 14, 2010 18:48:14 GMT by suterman
1985 Bedford CF2 camper 1991 Volvo 240 Turbo
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Sept 14, 2010 18:52:52 GMT
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for the price/weight difference I'd buy the thickest you can... it's a one time purchase ![;)](//storage.proboards.com/forum/images/smiley/wink.png) and remember that there are added bonuses to going thicker than the bare minimum... the engine will crank much faster and there will be less voltage drop to the fuel pump and ancilliaries (with a battery in the boot the current will have to do a complete lap of the car before getting to the pump via the engine loom) Any annoying niggle with car electrics that you can think of is amplified by a smaller battery cable... 150A cable will be woefully inadequate - it may handle the car running fine, but I wouldn't fancy it as doing a good job under cranking.... my car battery is 600CCA - pretty sure a 150-200A cable is going to restrict the battery a fair amount ![;)](//storage.proboards.com/forum/images/smiley/wink.png) As before I'd say buy as big as you sensibly can - it'll cost a fiver or tenner extra at most and on that icy winter morning when the car will barely turn over you'd have wished you paid the extra fiver, lol!
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- '80 Mk1 Vauxhall Cavalier Saloon, 3.0l 12v... in progress with some special plans ahead - '94 106 Rallye, Endurance Rally Car
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gazjon
Part of things
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Posts: 632
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Sept 14, 2010 19:18:16 GMT
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25mm(square) will be more than adequate for what you want it to do. Go for a silicon based insulator as it gives better oil/heat protection.
I can make you up any size lead you need with whatever ends you want, but it will be expensive to post it to you as good quality wiring at that length/thickness is very heavy.
As long as the cable is routed well, you shouldn't have to worry about fussing it. In my experience, if a pos cable spilts and connects to ground, it tends to burn out the few strands that touch rather than weld itself to the chasis. At which point you would have hopefully noticed/smelt it happen. It is better to be safe then sorry though, so go for a fast blow fuse thats of the correct amperage.
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Mk2 Cavalier saloon Mk4 Astra Van z20let
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Sept 14, 2010 19:18:43 GMT
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just because your car has a 600amp battery on it does not mean the starter can draw that much current, a biggish diesel engine draws about 500 on crank, my RR diesel had a 500amp cold crank battery on it, a 2 litre 4 pot petrol only draws about 200amps and that the highest load you'll see in a car.
Big heavy cable is harder to bend and route through the car, more expensive, needs bigger holes and grommits in the bodywork and bigger conections on the ends of it, i don't see why you'd want to fit bigger cable than you'd need?
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Volvo back as my main squeeze, more boost and some interior goodies on the way.
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gazjon
Part of things
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Posts: 632
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Sept 14, 2010 19:27:10 GMT
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Belt and braces I say. Its not a job you'll be wanting to do twice and allows for future upgrades to the lights/stereo/engine etc.
I use 35mm(square) cable on the works vehicles(buses) and its still easy to route and surprisingly supply as well. Just good quality cable I suppose.
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Mk2 Cavalier saloon Mk4 Astra Van z20let
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Sept 14, 2010 20:10:13 GMT
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I can make you up any size lead you need with whatever ends you want, but it will be expensive to post it to you as good quality wiring at that length/thickness is very heavy. (Cheeky threadjack/request) Could you possibly make me some please? I live in Brighton, work on my cars in Worthing & notice your location says much the same ;D not sure I'd want the mega-heavy stuff (as I'm going for maximum lightness) - what sorta ££ would I be looking at? ![8-)](//storage.proboards.com/forum/images/smiley/cool.png)
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Sept 14, 2010 21:08:38 GMT
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just because your car has a 600amp battery on it does not mean the starter can draw that much current, a biggish diesel engine draws about 500 on crank, my RR diesel had a 500amp cold crank battery on it, a 2 litre 4 pot petrol only draws about 200amps and that the highest load you'll see in a car. sure a good condition starter will draw 200A from cold then add on a good 20A for fuel pump with a bit extra, then the ignition system should be given some overhead... maybe the radio is on etc. You could fit a 200-250A cable to handle this cranking load fine... but there is no factoring for starter motor wear which would increase current draw (quite significantly in some cases) or future proofing the system. As I said before there is benefit in paying £5 or so more to have an engine that turns over faster, starts easier and has plenty of overhead. Also, this is a community that can't leave their cars alone... ![:D](//storage.proboards.com/forum/images/smiley/grin.png) - having the beefy cable is good as you never know what engine you might suddenly get the urge to fit next. Just my 2p, but I like to build reliable and build once when it comes to, lets be honest, a cheap and to some degree safety (everyone loves heated seats but rear passengers may not be expecting it from your battery cable...) related modification.
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Last Edit: Sept 14, 2010 21:10:20 GMT by jasonb360
- '80 Mk1 Vauxhall Cavalier Saloon, 3.0l 12v... in progress with some special plans ahead - '94 106 Rallye, Endurance Rally Car
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Sept 14, 2010 21:46:03 GMT
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OK so you reckon - as thick and heavy and as high amperage as poss and Ill be sorted? There are plenty of thick welding cables of massive amperages Ive found on ebay
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Sept 14, 2010 22:27:20 GMT
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why would welding cable be any cheaper than cable from your local auto / plant / tractor / lorry factor place? Running the cable in some of that flexible corrugated plastic conduit stuff will give it some more protection from abrasion.
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69 Plymouth Fury Convertible 75 Range Rover 2 door 82 Range Rover 4 door 84 Range Rover 4 door 78 Datsun 120Y 2 door 78 Datsun 120Y Coupe 78 Datsun 620 Pickup 81 Datsun Urvan E23 86 Datsun Vanette van 98 Electric Citroen Berlingo 00 Electric Peugeot Partner 02 Electric Citroen Berlingo 76 Honda C50 04 Berlingo Multispace petrol 07 Land Rover 130 15 Nissan E-NV200 15 Fiat Ducato
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maxlee
Posted a lot
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Posts: 1,200
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Sept 15, 2010 0:43:08 GMT
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i have the wires out of a 525td and its pretty hefty stuff also took the fittings out of a 325i e30 again pretty thick can get you a pic or to if you like on the 525 stuff??
bmw's use a block that your old battery termanl will atatch to as they didn't chance the wire or the ones i have broke up just added to it don't think i have one laying about will look in the morning
bmw's e30's etc did have a vent that was under the tray (one in e30 did) but i am guessing with careless batterey changes and diy they get lost or binned
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rtlkyuubi
Posted a lot
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Low and Slow
Posts: 2,922
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Sept 15, 2010 6:24:53 GMT
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Theres alot of proper right ways in this thread about doing this haha ;D In the viva I had the battery sat behind the passenger seat and was connected up using sub cable (15mm squared ish) Never blew up fron hydrogen and never melted the cable on cranking
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Sept 15, 2010 7:53:25 GMT
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Think welding cable is more pliable and a bit cheaper as there is more call for it. Ill be going for somewhere in the region of 300 amps, in as thick a wire as I can find, clamping it down in a fibreglass box (they aint cheap) and then puttin a piece of heater hose in there running to the rubber outlet in the boot for the fuel filler pipe - thanks for all your input guys - it seems to do it properly on a poor persons budget..... - you can't ![:D](//storage.proboards.com/forum/images/smiley/grin.png) Seen the price of them bloody fibreglass boxes??! ![:D](//storage.proboards.com/forum/images/smiley/grin.png)
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Sept 15, 2010 7:57:07 GMT
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Just found some battery boxes designed for campers for less than a tenner - wintastic ![:D](//storage.proboards.com/forum/images/smiley/grin.png)
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Sept 15, 2010 8:22:15 GMT
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sorted ![:D](//storage.proboards.com/forum/images/smiley/grin.png)
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- '80 Mk1 Vauxhall Cavalier Saloon, 3.0l 12v... in progress with some special plans ahead - '94 106 Rallye, Endurance Rally Car
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maxlee
Posted a lot
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Posts: 1,200
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Sept 15, 2010 9:08:57 GMT
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camper box sounds sweet my camra is flat but will get pics later my friend used a topbox of a old moped once had a lock and every thing just for giggles but worked
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