Jump starting?

Just wondering if anyone has caused any problems or know of any problems with jump starting? Is there a technique or anything that anyone knows to prevent any problems to the ECU or any other electrical equipment?

Cheers

I got a big lecture by an auto electrician about this, and he recommended the following technique:

1) Only do this if the assisting battery is in top shape
2) Disconnect the positive lead from the assisting battery
3) Connect the black lead to the negative on the assisting battery
4) Connect the other end of the black lead to the negative on the flat battery
5) Connect the red lead to the positive battery pole of the assisting battery
6) Connect the other end of the red lead to the positive on the flat battery
7) Start the vehicle being assisted
8) Disconnect the leads in reverse order
9) Return the positive lead to the assisting battery and start that car

Because all you're doing is using a battery (effectively), there's no possibility of any danger at all.

Personally I'd add a step just after step 1: "note down how many km on your trip meter", in case you're using that to calculate fuel economy.

what i've heard is:

1. have engine running on the assisting car
2. connect to assisting car battery positive and dead car positive
3. connect to assisting car battery negative and any earth point on the dead car (not the negative battery terminal.
4. start the dead car
5. remove jumper leads in reverse order (negative then positive)

these days you can buy jumper leads which have circuit protection in them, some sort of anti-spiking/surging device

first thing would be to use spike protected jumper leads.

i;m told the reason for the negative to go to chassis rather than the terminal is to avoid sparks when you connect it which could ignite the hydrogen gas emitted by the battery.
batterys can put out a fair bit of gas under heavy starting. so if you hav ebeen there cranking it over there can be a fair bit of gas build up.
a battery explosion is NOT fun.

the other thing is once connected leave it for 5 minutes. this allows the flat battery to charge up so your not trying to draw full power through a thin jumper lead with crappy terminals.
after all thats all those jump starting packs are.

I was taught the same way maddog suggests, use an earth point rather than the earth of the battery.

I was also taught to keep the assisting car running during the procedure which obviously means I don't disconnect the positive terminal. Starting in general takes a heap out of even a good battery momentarily, add to that any voltage drop across the leads (it may not be that much but it will be there) and the assisting battery if not in the best shape can quickly end up as stuffed as the first. If the engine is running at the time of cranking and the assisting battery staggers you can lift the revs of the assisting vehicle up to keep the recharge current of the assisting battery higher. Of course this can require two people but in most cases if there is two cars there is two people.

As with any procedure there is many theories, which one you subscribe to is probably as much about preference as it is about who you trust more when it comes to story telling. Do a hunt around the net and you'll probably find thousands of people who use either of the above ways and some who think it's all crap, you might even find some people who think they can do it telekenetically (it is the net after all). The best bit of advice would really be not to stick your tongue on the sparky bits, it may only be 12 volts but it's not the volts that kill you

Ive been told to earth the negative on the dead car too (not the terminal

The best way to do it if you don't have spike protected leads is to use a combination of old.tony's and earthing the negative lead on the chassis of the dead car.

BUT, if you disconnect the positive you will loose all you radio stations and stuff like that. So i depends how paranoid you are really.

I've jumped heaps of cars with out spike protected leads.

Probably the best advise I can give is to buy or MAKE some proper jumper leads with lots of copper in them (not just insulation making them look like thick wire) and good HD clamps to make good contact with the terminal

Also, use a wire brush to clean off corroded terminals before jumping.

For what its worth my 22 manual states pretty much what maddogrc says, with the bit others have said about allowing the assisting car to run for a few mins to charge the dead battery before starting dead car.

tweak'e said:

first thing would be to use spike protected jumper leads.

Click to expand...

This the one thing that any good set of leads will have and we're not talking about crap under $100 , The set of leads I have made up for my line of work is rated at 800amp's continuous with spike protecting in-line

Remember red on 1st and red off last let the flat battery stabilize for a few minuets and you should never blow any ECU's hell touch wood after 20yrs in the field (NRMA) I have never blown a computer yet

Cheers Marty

I usually do the connection as per Marty's description and then will bring up the revs on the good car to try to put a little charge in the dead battery, then try starting it .
And as Marty says only use quality leads. Cheap crappy leads can cause bulk damage
One other thing I will usually do is connect the NEG to the car engine itself so say the engine lift bracket or something solid thats directly bolted to the engine. Starter motor gets its earth from the engine so I just connect to the engine for the Neg.

What the guys who mentioned the spike protected leads said.

I have jump started about 10 vehicles using jumper leads. No dramas what so ever.

Dave.

spiking an ECU is fairly rare these days due to much better ECU design.
quite right about good leads. can be hard to tell as some big thick cabled ones are 50% rubber coating and thin wires.