Proper battery jump

jason_

Veteran Member
Joined
Jun 2, 2014
Location
michigan
TDI
2015 s wagon dsg
Now, I've always jumped the dead vehicle grounded through the block, but with a battery monitor module present, jumper or jumped vehicle, vw or not, is there a difference? If yes, explanation?


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oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
I don't allow my cars' batteries to die. But I obviously have to jump start a lot of stuff that gets towed in here, and I always go straight to the battery posts OR the specified jump start points on cars with remote/buried/limited battery access. The only exception is the Prius, where we just jump under the hood at the fuse junction box since it is low load anyway.

Honestly, though, jump starting really should be a last resort, because the car's charging system is NOT intended to recharge a dead battery, let alone one that may have an issue that will not allow it to take a charge in the first place. Better to put a dedicated charger on the battery and let it charge for a while (overnight if possible) in cases where the battery is likely OK but was discharged because something was left on or the vehicle sat for a really long time. If the battery is likely shot, like it suddenly died (usually happens in the heat) with little or no warning, or it is really old (depends on the car, the area, etc.) then just get a new one and save your charging system the stress.
 

jason_

Veteran Member
Joined
Jun 2, 2014
Location
michigan
TDI
2015 s wagon dsg
Oh, imagine those who try and start a vehicle with a stone dead battery, with jumpers still on...

Poor alternator....

I at the least pull one lead on the running vehicle so the charging system isn't taking the brute, just the batteries...

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Ol'Rattler

Top Post Dawg
Joined
Jul 3, 2007
Location
PNA
TDI
2006 BRM Jetta
Oh, imagine those who try and start a vehicle with a stone dead battery, with jumpers still on...

Poor alternator....

I at the least pull one lead on the running vehicle so the charging system isn't taking the brute, just the batteries...

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Could you explain what lead you are referring to?

My inclination is to allow the dead car's battery to charge off of the running car at a slightly elevated idle for about 10 minutes and then turn off the running car prior to starting the dead car. I agree. An alternator is not designed to supply starting current. A quick Google search says that the average car needs about 400 Amps to start.
 
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jason_

Veteran Member
Joined
Jun 2, 2014
Location
michigan
TDI
2015 s wagon dsg
Any lead.

Idea is so the car in distress will try and start off its own battery, not the helping battery, it's charging system, or through the $5 cheap battery cable jumpers most people use.

And 400 amps is a good number, but not all starters out there have good brushes cleanly against the armature.

A garbage starter with bad or worn brushes is nothing more then an arc welder set on DC...1 battery or 100 hooked up.

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Ol'Rattler

Top Post Dawg
Joined
Jul 3, 2007
Location
PNA
TDI
2006 BRM Jetta
Any lead.

Idea is so the car in distress will try and start off its own battery, not the helping battery, it's charging system, or through the $5 cheap battery cable jumpers most people use.

And 400 amps is a good number, but not all starters out there have good brushes cleanly against the armature.

A garbage starter with bad or worn brushes is nothing more then an arc welder set on DC...1 battery or 100 hooked up.

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That doesn't make any sense. If you disconnect the jumper cables, the dead car will be trying to start off of it's dead or almost dead battery. If you leave the jumper cables connected, the dead car will have both batteries for starting. If you turn off the engine on the jump car, the alternator is essentially taken out of the picture and can't be harmed.

Your method would work if you allowed the dead car to charge for about an hour off of the jump car.
 

jason_

Veteran Member
Joined
Jun 2, 2014
Location
michigan
TDI
2015 s wagon dsg
That doesn't make any sense. If you disconnect the jumper cables, the dead car will be trying to start off of it's dead or almost dead battery. If you leave the jumper cables connected, the dead car will have both batteries for starting. If you turn off the engine on the jump car, the alternator is essentially taken out of the picture and can't be harmed.

Your method would work if you allowed the dead car to charge for about an hour off of the jump car.
Exactly.

My method is prevention.

No stranger on the side of the road is worthy to risk roaching my electrical system, or increasing the risk of getting me stranded, especially with kids in the car.

If their battery is that ****ty if 15mins of a good alternator charging it doesn't whirl the starter fast enough, then they can call a specialized service., or as suggested a jump pack.

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