Thread: Modern Jumper Leads

You can damage a new vehicle jump starting it with old school lumperleads. but the you can do the same damage ump starting one with the newer leads.

a fair number of ducks have got to line up just right for it to happen.

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Ok so should I buy the ones with or without the surge protection? Some of the ones on ebay seem too cheap? The Matson ones look good but are 4 times the price, I am a great believer in quality though, so if that's the way to go, I don't ever want to buy another pair.


Most of them are way too short too BTW, 4m seems like a good length not sure.

Originally Posted by BadCo.

Something like this? 1000a clamps, 50mm2 and 6m long. Long enough to jump start a truck front to back

yep 👍

Originally Posted by spudboy

Jump Starting The Newer Engines.(D4 & Spt 3.0/5.0)
When jump starting these vehicles please do not place the +ve & -ve terminals from the jumper leads on your battery if you own one of the above. You will notice on the -ve side that there is a battery monitor. If you place the jumper leads on both the +ve & -ve terminals you will blow the battery monitor, causing many electrical faults & error messages. You will need to replace the battery monitor & then recalibrate it via a dealer(SDD programable).
...
It is a common practise not to place the jumper leads on the flattened battery terminals anyhow, as you can damage any number of ECUs in the vehicle, mainly engine ECUs.
Please take note of this as it may save you money.

Hi David, and that crap you linked to is what happens when journalists are used to write up technical information.

For a starter, the "EXPERT" is not using auto electrical symbols but is using ELECRTONICS sysbls and hasn't even got the correct symbols.

+ve means a voltage above ground/earth/0 volts.

-ve means a voltage BELOW ground/earth/0 volts.

If used correctly in an ELECTRONICS schematic, the correct use would be something like +12v and 0v

In an automotive schematic all you need is the positive voltage and there is no need to use the ( + ) as it is automatically accepted that the voltage is positive.

So the correct SCHEMATIC symbols should have been 12v and 0v, but in the case of a battery connection, it is simply ( + ) and ( - ) and that is all you will find on any automative 12v battery.

So the instant you see someone using the +ve and -ve symbols, it's pretty safe to assume they do not have an automotive electrical background and as such, be careful of what you read.

NEXT, It has been a NO-NO to connect the negative ( - ) jumper lead to a cranking battery's negative ( - ) terminal since automobiles first installed a battery, about a hundred years ago.

While there have been reports of a number of instances where the battery monitor on the negative lead from the D4's cranking battery to the earth mount has "allegedly" been damaged while attempting to jump start the D4.

Whether this is correct or not is of no interest to me because the negative jumper lead should never have been connected to the D4's cranking battery's negative ( - ) terminal in the first place, and not because it might damage anything in the D4 but because it has been a safety requirement for around a hundred years on ALL VEHICLES.

Again, the journalists who wrote that technical info, has no idea what he is writing about.

If you carry out a jump start correctly, ON ANY VEHICLE, you can use 8B&S size cable for the jumper leads, just make sure the clamps are a decent size and have a strong spring action.

__________________________________________________ __________________________________________

THE CORRECT WAY TO SET UP AND CARRYOUT A JUMP START.

Now whether the crippled vehicle's battery is flat or stuffed, it will still hold a surface charge, even if that is for just a few minutes. When jump starting a vehicle, you don't need it to hold that surface charge for more than a few seconds.

The correct procedure for jump starting a vehicle is as follows.

Bring the donor vehicle as close as practical to the crippled vehicle.

Leave the motor running in the donor vehicle at all times.

Many vehicles can draw quite high currents with the ignition key still in the switch ( up to 40 amps ).

Turn the ignition off and remove the kew from the ignition of the crippled vehicle. This is not done to protect the vehicle's electronics, this is done to remove any remaining current draw from the crippled vehicle's battery.

Note, in many new vehicle, not until you actually remove the ignition key will all current loads be turned off and in some vehicles, like new Land Rovers, the computers will remain active for up to 3 minutes, while they go through shut-down routines, after the key is removed.

Next, connect the positive lead to the crippled vehicle's positive ( + ) battery terminal, then connect the other end of the positive lead to the donor vehicle's positive ( + ) battery terminal.

Then connect one end of negative lead to the donor vehicle battery's ( - ) negative terminal.

Now find a suitable earthing point in the crippled vehicle's engine bay ( if the cranking battery is located there ). This earthing point should be a bolt or something of that nature.

Do not use any body parts as the earthing point.

Leave the vehicles connected with the donor vehicle's motor running at a high idle, for at least 2 minutes but 5 would be better.

Once some time has elapsed, try starting the crippled vehicles motor.

If it does not start straightaway, turn the crippled vehicle's ignition switch off and remove the key and give the crippled battery more charging time.

If the motor starts, remove the negative lead from both vehicles, then remove the positive.

By applying the negative ( - ) jumper lead last and removing the negative jumper lead first, if you drop either end of the positive ( + ) jumper lead while you are trying to connect to either battery, and it comes in contact with any body work or the motor of either vehicle, because the negative jumper lead is not in place, there is no completed circuit so there will not be a short.

Then when removing the positive lead, again, as there no longer a closed ( negative ) circuit, you will not risk causing a short.

DO NOT switch the crippled vehicle's motor off to test the crippled vehicles battery. If you are in the middle of nowhere and your motor is now running, don't tempt fate.

Originally Posted by Islandnomad

Ok so should I buy the ones with or without the surge protection? Some of the ones on ebay seem too cheap? The Matson ones look good but are 4 times the price, I am a great believer in quality though, so if that's the way to go, I don't ever want to buy another pair. Most of them are way too short too BTW, 4m seems like a good length not sure.

Mine are about 4m, red and black cable, about the weight of welding leads.

Originally Posted by drivesafe

Hi David, and that crap you linked to is what happens when journalists are used to write up technical information.

For a starter, the "EXPERT" is not using auto electrical symbols but is using ELECRTONICS sysbls and hasn't even got the correct symbols.

+ve means a voltage above ground/earth/0 volts.

-ve means a voltage BELOW ground/earth/0 volts.

If used correctly in an ELECTRONICS schematic, the correct use would be something like +12v and 0v

In an automotive schematic all you need is the positive voltage and there is no need to use the ( + ) as it is automatically accepted that the voltage is positive.

So the correct SCHEMATIC symbols should have been 12v and 0v, but in the case of a battery connection, it is simply ( + ) and ( - ) and that is all you will find on any automative 12v battery.

So the instant you see someone using the +ve and -ve symbols, it's pretty safe to assume they do not have an automotive electrical background and as such, be careful of what you read.

NEXT, It has been a NO-NO to connect the negative ( - ) jumper lead to a cranking battery's negative ( - ) terminal since automobiles first installed a battery, about a hundred years ago.

While there have been reports of a number of instances where the battery monitor on the negative lead from the D4's cranking battery to the earth mount has "allegedly" been damaged while attempting to jump start the D4.

Whether this is correct or not is of no interest to me because the negative jumper lead should never have been connected to the D4's cranking battery's negative ( - ) terminal in the first place, and not because it might damage anything in the D4 but because it has been a safety requirement for around a hundred years on ALL VEHICLES.

Again, the journalists who wrote that technical info, has no idea what he is writing about.

If you carry out a jump start correctly, ON ANY VEHICLE, you can use 8B&S size cable for the jumper leads, just make sure the clamps are a decent size and have a strong spring action.

__________________________________________________ __________________________________________

THE CORRECT WAY TO SET UP AND CARRYOUT A JUMP START.

Now whether the crippled vehicle's battery is flat or stuffed, it will still hold a surface charge, even if that is for just a few minutes. When jump starting a vehicle, you don't need it to hold that surface charge for more than a few seconds.

The correct procedure for jump starting a vehicle is as follows.

Bring the donor vehicle as close as practical to the crippled vehicle.

Leave the motor running in the donor vehicle at all times.

Many vehicles can draw quite high currents with the ignition key still in the switch ( up to 40 amps ).

Turn the ignition off and remove the kew from the ignition of the crippled vehicle. This is not done to protect the vehicle's electronics, this is done to remove any remaining current draw from the crippled vehicle's battery.

Note, in many new vehicle, not until you actually remove the ignition key will all current loads be turned off and in some vehicles, like new Land Rovers, the computers will remain active for up to 3 minutes, while they go through shut-down routines, after the key is removed.

Next, connect the positive lead to the crippled vehicle's positive ( + ) battery terminal, then connect the other end of the positive lead to the donor vehicle's positive ( + ) battery terminal.

Then connect one end of negative lead to the donor vehicle battery's ( - ) negative terminal.

Now find a suitable earthing point in the crippled vehicle's engine bay ( if the cranking battery is located there ). This earthing point should be a bolt or something of that nature.

Do not use any body parts as the earthing point.

Leave the vehicles connected with the donor vehicle's motor running at a high idle, for at least 2 minutes but 5 would be better.

Once some time has elapsed, try starting the crippled vehicles motor.

If it does not start straightaway, turn the crippled vehicle's ignition switch off and remove the key and give the crippled battery more charging time.

If the motor starts, remove the negative lead from both vehicles, then remove the positive.

By applying the negative ( - ) jumper lead last and removing the negative jumper lead first, if you drop either end of the positive ( + ) jumper lead while you are trying to connect to either battery, and it comes in contact with any body work or the motor of either vehicle, because the negative jumper lead is not in place, there is no completed circuit so there will not be a short.

Then when removing the positive lead, again, as there no longer a closed ( negative ) circuit, you will not risk causing a short.

DO NOT switch the crippled vehicle's motor off to test the crippled vehicles battery. If you are in the middle of nowhere and your motor is now running, don't tempt fate.

Sent from my C6903 using AULRO mobile app

My jumper leads are Michelin Smart Jumper leads and are non-polarised so anyone can use them with worrying about connections.

They supposedly have spike suppression built in.

Michelin Smart Jumper cables for easier jump-starts - CNET

Ok so should I buy the ones with or without the surge protection?


As an aside the ones with the surge detector have it very close to the end of the cables, must be a tight fit onto some batteries??