Jump Starting Another Car,Is It Safe To?

tonycarew

Thanks all for the replies,there's certainly food for thought.

thescouselander

maninthestreet wrote: »

It's no longer that simple or straightforward with modern cars. Some cars cannot be jump-started without causing damage to their electronic systems. Before attempting to jump-start any vehicle, first check the handbook for both cars involved to see if they state the cars can be jump-started.

Well I wouldn't want to encourage anyone to disregard what it says in the hand book but it might just be a case of the maunfacturer not trusing the owner to do the proper proceedure.

There is no reason why you cant jump start any car unless there is a fundimental difference such as the electrical systems running at different voltages. For the moment, most cars are still running on 12V.

pitkin2020

thescouselander wrote: »

Well I wouldn't want to encourage anyone to disregard what it says in the hand book but it might just be a case of the maunfacturer not trusing the owner to do the proper proceedure.

There is no reason why you cant jump start any car unless there is a fundimental difference such as the electrical systems running at different voltages. For the moment, most cars are still running on 12V.

yes most manufacturers are going to air on the side of caution, but certain electronic components can be effected and blow from the surge when jump started, in car sat navs are known for one, but there also reports ECU errors etc from jump starting

Pew_Pew_Pew_Lasers!

jamesb1239 wrote: »

I think the connecting the negative lead to the chassis is something to do with the fuses in the car and power surges, not sure though, maybe someone can clarify that.

Its more to do with starting a fire by creating a circuit between two high capacity batteries.

thescouselander

pitkin2020 wrote: »

yes most manufacturers are going to air on the side of caution, but certain electronic components can be effected and blow from the surge when jump started, in car sat navs are known for one, but there also reports ECU errors etc from jump starting

Yes but as I said, the danger of damage is more likely to be from static discharge as the cars are connected togeather. Once the connection is made the cars electrical systems dont care if the electrical source is the cars own battery or the donor car. It is not possible to get a "surge" during the rest of the jump starting process.

Most likely any ECU errors would be caused by a low voltage condition during start if the jump lead connection is poor and has a lot of resistance - thats why its best to try and charge the dead battery for 10 mins so it can assist with the starting load. Also the connections need to be checked to make sure they are good, I usually test the lights to make sure they come on nice and bright to be sure of a good connection.

colino

Starting a car in the yard I always use a booster pack "just in case". But I don't honestly know anyone personally who has suffered from a fatal spike problem. If you need to use the jump leads, put the headlights on the dead car on to provide a buffer and as said previously, don't hook up to the negative terminal on the dead battery, use a bright metal contact in the engine bay. This is to provide juice to the starter and electrics, not trying to recharge the dead cells of the flat battery.

goldspanners

jamesb1239 wrote: »

I think the connecting the negative lead to the chassis is something to do with the fuses in the car and power surges, not sure though, maybe someone can clarify that.

nope, its incase either slave or dead battery is gassing,which could cause either battery to explode if a source of ignition ( a spark from jump leads) is present.

Hintza

I saw this thread just after OP had posted and had written a reply before deciding not to post.

I think I was justified in not doing so (I was going to take my normal gung ho approach ). Probably manufacturers taking the better safe than sorry approach but as with all things in life nothing is simple any more.....:(

hewhoisnotintheknow

just to add in, my 2009 golf needed jump starting as it would always loose charge over night for no reason (it had been in and out of the garage at least 5 times for this fault), one morning i jump started it as usual, and it cooked the ECU and a part in the dash also needed replacing