Question for techies DIY Jump leads

[Mike Whitworth]

I want to make some jump start leads to carry on the bike for emergencies ( theory being if you carry a tool you will never nead it ) What thickness / guage wire is necessary for a set of jump leads? Obviously I want to make a set smaller/ more convenient to store on the bike than your typical Halfords leads.

Regards to all
Mike

 

[TERRY RYAN]

Look at Nippys site you can buy them from him

 

[Tarka]

Given the cold cranking current of a BMW twin,you`ll likely torch a 'typical set of Halfords' leads in the time it takes to start yer bike ...so anything smaller will be a waste of time,effort,money and space... don`t bother.

 

[Timolgra]

use a couple of luggage straps to tow start the bike IF you ever need to

just put a loop over opposite footrests of each bike

 

[Stanley Knife]

I have had good results with a home made set using extra thick copper cored speaker wire soldered to a female end auxiliary socket connected to the battery (without inline fuse) and mounted on the air box lid,another longer length of wire with a male socket on one end and two crocodile clips on the other neatly stores in a spare space in the relay box.

I have used this several times to jump start my bike and also to start others from mine but only when the other battery is not completely flat,I don't think it would flow enough current for that.

It has saved me a lot of hassle at rallies when bump starting would not have been an option.

I am not sure what thickness of wire I used it was just some I had left over from upgrading my speaker cables,but a good a hifi shop should sort you out with some good thick stuff that is still flexible.

 

[Greg Masters]

The starter will draw something like 200-300 amps when it bites. Some of that demand will come from you bike's battery, but if it's totally flat, thhe current all has to come though your jump leads.

To give you an idea of what 300 amps is, go and find some 15 amp fuse wire, then twist 20 strands of it together.

Your leads, therefore, need to be of about the same gauge as the earth strap between the battery and the frame.

Greg

 

[Loiq]

well I'm not sure if making jump leads is a good idea, would always go for the tow strap option. Much safer if you get that wrong you can always try again or just tow the bike to a place to fix it. If you stuff the electrics it's game over no more credits, no second go your are now a pedestrian.

if you really unlucky it'll vapourise the cable and your fingers with it.

 

[Lord Snooty]

I bought a kit (from Wunderlich I thnk) which consists of two parts. One part is permanently wired to the battery and the wires enter a circular plug and it all tucks away nicely. The second part is the jumper leads themselves with the crocodile clips and that also has a plug which obviously pushes into the underseat plug.

 

[scots_jon]

Leads don't need to be all that big, the instantaneous breakaway current is rather large, but the cranking current ain't so bad probbaly around 25-50A depening on temperature etc.

Halford sell a set a motorcycle jump leads for a round a fiver that are idea, I used these regularlly until I got round to replacing the battery.

The other option is to wire in the jumping connector you can buy form Nippy Normans or a standard 50A Andrews connector.

I have the nippy Normans one wired in now, it was easy to fit at the same time as replacing the battery with a Hawker.

Jon.

 

[GSmonkey]

As long as you're not going to sit there cranking it over for hours on end, the real limiting factor is volt drop. If you make the wires too small, you'll have too low a voltage at the receiving bike's end.

 

[Mike Whitworth]

Re Jump leads

Thanks Guys for all the replies

Mike

 

[Lord Snooty]

Wunderlich Bikestart Kit

I have more info for you:

The kit I mentioned is called a Bikestart Kit, it is listed in the Wunderlich catalogue as part 2024568 and cost €31.90.

 

[prul]

The Bikestart kit works, with an unwilling R100GS and a running F650 and the other way around allso

 

[Helmetrock]

I have made a pair of starter cables for my Rockster, I took a pair of car cables and took one end of, then I cut of 300mm (12in) pieces that I attached to the battery.

Then I took some high current contacts, for example fork lift charging contacts.

If the battery run dry, I just take the seat off, connect the clamps to another battery, and then put the contacts together!

I have some pictures in the Swedish BMW MC forum, but it's in swedish of course

http://forum.bmw-mc-klubben.se/showthread.php?t=1488

In the last post they are finished

/Rickard

 

[MiGSel]

These are the ones I made years ago.

 

[Helmetrock]

These are the ones I made years ago.

But isn't it a struggle to get the clamps on the battery posts?

On mine there are always short leads to the battery, and then you just put the contacts together.

Or did I miss anything? Any hidden secret MiGSel?

 

[Timolgra]

But isn't it a struggle to get the clamps on the battery posts?

One screw removes the starter cover. Use the pos. there.