I'm going out today to buy some jumper leads, but I'm not quite sure what to get.

Supercrap has a hole lot of different leads, from

- 100amp leads for $23
- 200amp leads for $28
- 400amp leads for $43
- 750amp leads for $73.

What is the difference, and what am I best getting? I'm not going to be jumpstarting a prime mover, just things mini sized up to 4wd sized I suppose.

Cheers

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"I'm sorry, but a lack of planning on your part does not constitute an emergency on my part!"

Those are all crap really, but the bigger the better.
I'd like to see the voltage drop when they are passing their rated current.

A starter will pull over 200A when cranking, and you want minimal voltage drop.

I make my own, from 24mm² welding cable and 300A earth clamps... cost me about $75 for a 3M set.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Everyone seems to say to make your own, but I wouldn't know how.

Where do you get your welding cable and clamps from? How do you attach the wire from the cable to the clamps?

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"I'm sorry, but a lack of planning on your part does not constitute an emergency on my part!"

Doc's spot on as always. Bigger is always better....but this is a relative matter when it comes to anything involving copper conductors from supercheap repco or autobarn.

If you really want fine cables, then 70sqmm flexible cable terminated with utilux crimps bolted to your clamps make for heirloom quality cables...the type you would want your granddad to pass down to you...

Cable can be had from places like Ideal, clipsal, Laurance and Hanson (L&H). Same with the crimps. Welding supplies have earth clamps which are real quality.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I say 70 sqmm because 90 sqmm is rated for 100 Amps continuous, but you will only use it for a few minutes which is perfect. You can start a car which hasn't even got a battery fitted to it with this size of cable.

As you go down then voltage drop increases at full load which reduces starter torque by the square of the difference. They don't get that much larger for the jumps in size either.

You're always going to be limited by the contact area of the clamps, always try to maximise the amount of clamp you have contacting the metal posts, even with cheap sets.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I buy my cable from industrial welding supply shops.
You need:
4 earth clamps, 300A min
4 cable lugs, for 24mm2 cable
6M (or whatever) of 24mm² welding cable (yes bigger is better but 24mm² is HUGE compared to normal `jumper leads'). This will give you a lead set 3M long which is fine for most use. (Ask Mini_Mad how it works, he has a set)

I solder the lugs to the cables with a 600C hot air gun and rosin cored solder. A propane gas torch works fine too. Watch you don't burn the cable coating.Forget a soldering iron for lugs this big.

When cooled, whip some PVC tape around the cable ends to finish them off.

Then I paint 2 clamps red, and the other 2 black.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

How long do they take to make and how much do they weigh?

Are you interested in making me a set if I pay for materials, postage, and beer money Doc?

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"I'm sorry, but a lack of planning on your part does not constitute an emergency on my part!"

Making your own you'll end up with an expensive but good quality set, you want to be able to depend on them when you need them.

I have found that the cheap sets can be OK if you solder the connections, they are only crimped and are really poor.

100 or 200 amp should do it OK for a Mini. The bigger sets get bulkier to store, which is where they are most of the time.

Would it be worth looking at a 4wd supply shop?

I tend to find when it comes to stuff like that there's usually better quality stuff available if you're willing to pay for it from the hard core shops...

Possibly worth trying. Have a good look at the clamps, usually this is where they try to save money and I'think you'll find most manufactured sets have crimped in cables which is what will let them down.

Jaycar have all the stuff you need;-

Red Cable
http://www1.jaycar.com.au/productView.a ... BCATID=491

Black Cable
http://www1.jaycar.com.au/productView.a ... BCATID=491

Clips
http://www1.jaycar.com.au/productView.a ... BCATID=516

Don't be tempted to make them too long, the voltage drop will make them less effective.

MOWOG, that lead says


Does that mean it's 200amps, the same as the cheapie ones from Supercrap?

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"I'm sorry, but a lack of planning on your part does not constitute an emergency on my part!"

You'll find it better than those, the stuff from jaycar is OFC which means it is a lower resistance (less voltage drop) than the stuff from supercrap. And the clips are infinitely better.

<EDIT> It has a 200 amp contiuous rating, so for jump starting, they'll do 400 Amps+ (Short Time Rating)

If you have a good auto electrician nearby you might be able to get him to solder the ends onto the cable according to DrMinis directions.

So I've been googling, and Toowoomba Welding Supplies sells
.........I take it that you've got the 25mm cable Doc?

If I buy the cable from there, would the Jaycar clips that MOWOG posted be ok? Or should I look for something more heavy duty?

Is joining them up something that a auto electrician should do? My father in law is a boilermaker, so would he be able to join them? Weld them??

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"I'm sorry, but a lack of planning on your part does not constitute an emergency on my part!"