Jump starting a VW van

ElephantBoy57

My works VW Crafter van has a dead battery, the last time I tried to start it with my car I failed.

The battery is under the seat, there is a positive terminal near the engine, I seem to recall putting the negative cable on the body.

If I do it that same way, but leave the car running for a while, will it charge the battery from those connections?

mattyprice4004

Yes - it should do, however the last time I failed to jump start anything was because I had weedy, useless jump leads. 
If the cable is only as thick as the cable on your household kettle I wouldn't bother trying - invest in a good set, and you'll start it no bother. 
The thickness of the cable on my 'commercial' leads (found in Aldi, of all places!) is about 1.5cm, and they're fairly weighty too. I've jump started a Sprinter with them a few times with no bother. 

ElephantBoy57

mattyprice4004 said:

The thickness of the cable on my 'commercial' leads (found in Aldi, of all places!) is about 1.5cm, and they're fairly weighty too. I've jump started a Sprinter with them a few times with no bother. 

They are quality cables, but around 40 years old.

neilmcl

You need to let your car run for a bit before trying to start the van, especially if the battery is completely dead.

Norman_Castle

If you cannot put the negative onto the engine block I'd use the battery terminals. If the vans diesel and the car is petrol you might struggle as the alternator output is lower. If it keeps failing to start and the vans battery is completely dead I'd borrow or buy a charger.

oh_really

If its got previous and is being used, I'd be looking at the work fitting a new battery after confirming charging circuit performance.

Paula_Smith

Have you checked the connectivity between each end of each jump lead. The last time we failed to jump start a car was because one of the leads had a bad connection at one end - we remade the connection and all was well again.

mcpitman

ElephantBoy57 said:

mattyprice4004 said:

The thickness of the cable on my 'commercial' leads (found in Aldi, of all places!) is about 1.5cm, and they're fairly weighty too. I've jump started a Sprinter with them a few times with no bother. 

They are quality cables, but around 40 years old.

@ 40 years old, they may have broken down or deteriorated

Mutton_Geoff

Norman_Castle said:

If you cannot put the negative onto the engine block I'd use the battery terminals. If the vans diesel and the car is petrol you might struggle as the alternator output is lower. If it keeps failing to start and the vans battery is completely dead I'd borrow or buy a charger.

The issue is the capacity of the battery, not the alternator output of the car since you won't be attempting to start the van with the alternator of the car, but it's battery. Start the car, connect the jump leads and leave the car on fast idle for 20 mins (or better moneysaving, buy a charger). Then attempt to start the van after you've delivered some charge to the battery.

Look at the battery capacity of the van (diesel?) and the car (petrol?). That is the issue.

AdrianC

Certainly alternator output is irrelevant - but the issue isn't even battery capacity. A cheap eBay LiIon jumpbox has a capacity of maybe 10Ah, yet will start damn near anything 12v.

It's voltage, pure and simple. The reason crappy jump leads don't work is simply voltage drop over high resistance connections. And voltage drop worsens as you try to pull more current down high-resistance connections.

ElephantBoy57

I have tried and failed. I left my car running probably over 30 minutes, it got power to the ignition, but not enough to turn over the engine.

It ended up just nothing, which is what happened last time, months ago. I think the computer must have sensed an issue, not a clue really. Something came up on the dashboard.