Jump start? Bump start? Car NOT MH

[Rapido925M]

My 2y old car wouldn't start and the local dealership sent a guy out (we are shielding) so they could see about replacing the battery under warranty (otherwise £150ish).

He turned up without a jump-start pack and no jump-leads: needless to say he failed!
I acquired a jump-pack from a family member and 3 times the guy tried to connect black to positive, red to negative BUT I stopped him.
Eventually he agreed to go red-red, black-black: he failed because the pack was low on power.

He then suggested towing the car to give a jump-start. I refused.
My car is still here!

His boss says:
connecting black of a jump-pack to negative via an earth point is not necessary, although both the handbook and the battery carry warnings about doing this.
using jump-leads is dangerous as voltage spikes can damage the electronics.
My brother says jump-starts are also forbidden on modern vehicles.

Any facts about these points would be welcomed.

TIA - Gordon

PS It transpired that the guy was a cleaner, not a mechanic. Thank goodness for that!(?)

 

[Vipar]

My modern car manual tell you how to connect jump leads

 

[Kannon Fodda]

Trying to start modern vehicles from a push or tow start can be a risk. Most have cam belts and if the engine is rotated incorrectly back from the wheels this can be pulled out of alignment.

Jump starting (from a second battery), may create risks to the car's electronics particularly the ECU, but also wrongly strain the alternator. The use of a start pack must be preferred to the use of a second vehicle, as you can really screw the electronics when theoretically two separate cars become interconnected by the jump leads so both donor and slave vehicle may be working against each other.

But if your battery is flat, what are you going to do and a majority of vehicles will give instructions for jump starting, with warnings against the push start.

 

[Geo]

My modern car manual tell you how to connect jump leads

Has anyone thought of starting a forum whereby you just boast about things instead of sharing.
Just wondered?

 

[Garfields]

Jump leads should be fine as long as they are connected correctly
Bump / push start is a no no
Its the risk of unburnt fuel into the cat rather than damage to the cam belt that's the problem
I had a look in the manual for our car and it give the normal instructions for a jump start

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[PaulyP]

My 2y old car wouldn't start and the local dealership sent a guy out (we are shielding) so they could see about replacing the battery under warranty (otherwise £150ish).

He turned up without a jump-start pack and no jump-leads: needless to say he failed!
I acquired a jump-pack from a family member and 3 times the guy tried to connect black to positive, red to negative BUT I stopped him.
Eventually he agreed to go red-red, black-black: he failed because the pack was low on power.

He then suggested towing the car to give a jump-start. I refused.
My car is still here!

His boss says:
connecting black of a jump-pack to negative via an earth point is not necessary, although both the handbook and the battery carry warnings about doing this.
using jump-leads is dangerous as voltage spikes can damage the electronics.
My brother says jump-starts are also forbidden on modern vehicles.

Any facts about these points would be welcomed.

TIA - Gordon

PS It transpired that the guy was a cleaner, not a mechanic. Thank goodness for that!(?)

If he was a cleaner did he at least wash the car whilst he was there.

 

[busbuddy]

Most modern cars have jump points clearly identified under the bonnet because access to battery is non existent

 

[rod_vw]

Most modern vehicles that are Euro 6 and have 'Stop/Start' technology have battery status monitoring which is normally a small unit in the -ve battery cable.
To ensure that this is not 'confused' -ve jump lead should be connected to the chassis earth point. This is often marked for this very purpose and indicated in the drivers hand book.

 

[pappajohn]

I really can't get my head around this voltage spike thing.
Whats the difference between connecting a fully charged doner battery to a dead battery or replacing the dead battery with a fully charged one? It's the same voltage.
If anything the dead battery will absorb and smooth any power from the doner battery.
If starting from a running car leave the ignition OFF and let the dead battery charge for 10 minutes.

 

[Rapido925M]

Most modern vehicles that are Euro 6 and have 'Stop/Start' technology have battery status monitoring which is normally a small unit in the -ve battery cable.
To ensure that this is not 'confused' -ve jump lead should be connected to the chassis earth point. This is often marked for this very purpose and indicated in the drivers hand book.

My feelings exactly, but the Service Manager said it wasn't a problem to go straight to the battery terminals (easily accessible) rather than follow the instructions in the handbook and clearly printed on the battery.

Given that the guy who came out was a cleaner (NO, he didn't do that task but was happy to sit and have a fag while I drove 10miles to get my SiL's jump pack)) I wonder
1) What damage (confusion?) would be done assuming he had actually got a fully charged pack connected the correct way round?
2) How would the Dealership respond to anything needing replacement as a result of his actions?
3) WHAT would be the effect of connecting the jump-pack the wrong way round? (I recall many years ago shorting a spanner across the battery terminals: that was quite impressive but at least it fell off. Crocodile clamps would ensure both remained joined! I'm imagining fire, possibly boiling acid, exploding battery?)
4) Would they blame me for providing a non-approved jump-pack? (Which may no longer have existed!)

TIA again - Gordon

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[rod_vw]

My feelings exactly, but the Service Manager said it wasn't a problem to go straight to the battery terminals (easily accessible) rather than follow the instructions in the handbook and clearly printed on the battery.

Given that the guy who came out was a cleaner (NO, he didn't do that task but was happy to sit and have a fag while I drove 10miles to get my SiL's jump pack)) I wonder
1) What damage (confusion?) would be done assuming he had actually got a fully charged pack connected the correct way round?
2) How would the Dealership respond to anything needing replacement as a result of his actions?
3) WHAT would be the effect of connecting the jump-pack the wrong way round? (I recall many years ago shorting a spanner across the battery terminals: that was quite impressive but at least it fell off. Crocodile clamps would ensure both remained joined! I'm imagining fire, possibly boiling acid, exploding battery?)
4) Would they blame me for providing a non-approved jump-pack? (Which may no longer have existed!)

TIA again - Gordon

Your assumptions about the results are quite correct!
There would at least have been a lot of sparks which may have discouraged him from finally clipping the croc-clips on.
At worst there would have been an explosion probably blowing the top off the battery and showering anyone close with battery acid (sulphuric acid) and parts of the battery with serious consequences!