Was he pushed or should he have jumped

[real4star]

I accidentally left the sidelights on on Dads Land Rover, so I had to use the starting handle this morning to save the battery (it wasn't flat but the starter would have finished it off)
Once running I left it on fast idle to warm up and let the dynamo charge the battery whilst I eavesdropped my neighbour.

His car (Volvo V70 auto)also had a flat battery and was being tended by a home-start mechanic who was explaining that modern cars couldn't be 'jumped' as this would damage the electronics and you can't push/bump start a double clutch auto transmission. Hence he recommend fitting a new battery

Sounded like bks to me... I'm 99% certain diesel Volvo's don't have double clutch auto's. But as I've not had any personal experience working on the oily bits of a really new car I kept quiet.

So as far as 'jumping' and 'bumping' new cars is concerned...

How much of what he said was accurate or was he trying to dazzle his customer with techno babble in a (successful) attempt to separate him from his hard earned?

Neal

[Codswallop]

real4star said:

was he trying to dazzle his customer with techno babble in a (successful) attempt to separate him from his hard earned?

^^ That. That particular home mechanic is a twunt.

[mini me]

I'm forever jump starting vehicles here at work which are so modern they aren't even in production yet. It's rubbish saying you can't. Volvo did do a double clutch auto in the 2 ltr diesels and I imagine you would struggle to bump start because of this.

[CampDavid]

mini me said:

I'm forever jump starting vehicles here at work which are so modern they aren't even in production yet. It's rubbish saying you can't. Volvo did do a double clutch auto in the 2 ltr diesels and I imagine you would struggle to bump start because of this.

Try telling that to someone who'd tried bumping a Maserati Quatroporte...

When jumping you'll spike the current with both batteries in the system. That's what kills electrical gubbins.

The correct answer is to use a battery charger.

[trickywoo]

I thought the main reason for not bump starting was the risk of putting too much unburnt fuel through the cats and thus damaging them.

Lead acid batteries hate being more or less 100% flattened so I'd guess that you have at the minimum reduced the life of yours.

[mat777]

jumping is possible, you just have to follow the very specific instructions in the user manual so as not to damage the electronics systems. My D2 has a guide to jumping that involves connecting in a specific order then using the other car to charge the dead battery rather than trying to start with the dononr battery immediately

[SimonV8ster]

I think you have to be more careful about *what you are jumping it from* - from a much larger battery/current could frazzle some electric stuff.

• could be rubbish*

[EDLT]

mat777 said:

jumping is possible, you just have to follow the very specific instructions in the user manual so as not to damage the electronics systems. My D2 has a guide to jumping that involves connecting in a specific order then using the other car to charge the dead battery rather than trying to start with the dononr battery immediately

There has always been a specific order to connect the jump leads, and you're supposed to let the running car charge both batteries for a while.

[aw51 121565]

Codswallop said:

real4star said:

was he trying to dazzle his customer with techno babble in a (successful) attempt to separate him from his hard earned?

^^ That. That particular home mechanic is a twunt.

This may be so, but he's not enough of one to lose sight of potential commission .

[mrmr96]

SimonV8ster said:

I think you have to be more careful about *what you are jumping it from* - from a much larger battery/current could frazzle some electric stuff.

• could be rubbish*

Not sure about that. Volts matter, and all car batteries (in the main) are 12V. So I don't see the problem myself. Even a big 12V battery is only 12V.

[Krikkit]

mrmr96 said:

SimonV8ster said:

I think you have to be more careful about *what you are jumping it from* - from a much larger battery/current could frazzle some electric stuff.

• could be rubbish*

Not sure about that. Volts matter, and all car batteries (in the main) are 12V. So I don't see the problem myself. Even a big 12V battery is only 12V.

Exactly - connecting a 600A battery to a car that only has a 100A battery as standard will make no difference. The current is drawn from the battery, not forced into the circuit. Of course, using a 24V battery on 12V electrics is a recipe for disaster.

I'm not sure where the problem with jumping comes from on newer cars - presumably battery condition checking circuitry etc is a bit sensitive?

[LuS1fer]

Krikkit said:

I'm not sure where the problem with jumping comes from on newer cars - presumably battery condition checking circuitry etc is a bit sensitive?

I suspect the issue is getting it wrong and frying electrics - something you would still do on older cars but with more salvageable results.

[Ozzie Osmond]

real4star said:

starting handle

real4star said:

dynamo

Spock! Analysis please!

[mrmr96]

LuS1fer said:

Krikkit said:

I'm not sure where the problem with jumping comes from on newer cars - presumably battery condition checking circuitry etc is a bit sensitive?

I suspect the issue is getting it wrong and frying electrics - something you would still do on older cars but with more salvageable results.

But what's the difference between hooking in a new battery and hooking up jump leads?

When I'm working on my car I sometimes need to disconnect the battery to make things safe. When I hook it back up it sparks a bit, but touch wood no problems. I can't see how swapping a battery for a new one is any different. Nor can I see how connecting another 12V battery in parallel will be any different either. If the car can cope with having a battery fitted or swapped, then surely it can cope with jumping? (So long as you do it right of course.)

[steve_bmw]

Most cars/vans these days have jump start points under the hood, usually a + on the bulkhead under a cover and a - maybe a big bolt on the chassis or instructions where to put the earth lead, usually the engine hanger bracket.

[blaineuk]

Volvo is an auto, so can't be bump started, and if the battery has gone flat, there is a good chance of it happening again once winter gets colder.

[mrmr96]

blaineuk said:

Volvo is an auto, so can't be bump started, and if the battery has gone flat, there is a good chance of it happening again once winter gets colder.

Depends why it went flat. If it was because the car was stood for an unusual length of time (e.g. whilst they were on holiday) then it would probably be fine. Similarly if it was because an item had been left in the ciggie lighter, or an interior light left on then also, probably fine. If the battery is on its way out then a new one will help. But it could also be an alternator problem or a whole host of other things. Simply replacing a battery because it went flat once is NOT necessarily the answer without knowing more.

[LuS1fer]

mrmr96 said:

But what's the difference between hooking in a new battery and hooking up jump leads?

When I'm working on my car I sometimes need to disconnect the battery to make things safe. When I hook it back up it sparks a bit, but touch wood no problems. I can't see how swapping a battery for a new one is any different. Nor can I see how connecting another 12V battery in parallel will be any different either. If the car can cope with having a battery fitted or swapped, then surely it can cope with jumping? (So long as you do it right of course.)

I meant connecting to the wrong terminals - amazing the number of people who think red should go to black....

[real4star]

Ozzie Osmond said:

real4star said:

starting handle

real4star said:

dynamo

Spock! Analysis please!

The joys of 1960's tech

Neal

[Wulluff]

real4star said:

I accidentally left the sidelights on on Dads Land Rover, so I had to use the starting handle this morning to save the battery (it wasn't flat but the starter would have finished it off)
Once running I left it on fast idle to warm up and let the dynamo charge the battery whilst I eavesdropped my neighbour.

His car (Volvo V70 auto)also had a flat battery and was being tended by a home-start mechanic who was explaining that modern cars couldn't be 'jumped' as this would damage the electronics and you can't push/bump start a double clutch auto transmission. Hence he recommend fitting a new battery

Sounded like bks to me... I'm 99% certain diesel Volvo's don't have double clutch auto's. But as I've not had any personal experience working on the oily bits of a really new car I kept quiet.

So as far as 'jumping' and 'bumping' new cars is concerned...

How much of what he said was accurate or was he trying to dazzle his customer with techno babble in a (successful) attempt to separate him from his hard earned?

Neal

An old LR I can understand but why the flat batt on a V70? Unless it's knackered and needs replacing ?