Jump Starting - A Problem Or Not

[pauljoanss]

Have just had a bad day. Left lights on overnight and battery flat this morning.

Tried jump starting with friend but lots of messing with poor contact thro cheap clips them "Engine Malfuction" come up on dashboard and refused to do anything after that.

Called Direct Line Breakdown man, he very quickly diagnosed broken (short/cell out, whatever) battery. He also gave very severe warnings about not jump starting modern cars and said there could be further very expensive damage.

Gave me choice to go and buy a battery or pay cash £80 for one from his van. Choose to buy his, just to keep his goodwill and save time but started to worry as I went to cash point "is this a con". Decide I would keep old battery so could carry out my own check later but breakdown man said it was an exchange deal only. After new battery fitted he then appeared to have lots of problems resetting engine malfunction and said problems connecting to car ECU, I was getting VERY worried. But he then produced a bigger looking control unit and proceeded to re-install the car software. Much to my relieve the car started and all was well. I was £80 poorer but at that point in time I would have paid a lot more to get the car running. He said if the ECU had been damaged it could have cost £1800 so I was very pleased to get away with £80. Two questions:-

1) Was I conned, many facts of the case appear to indicate a possible con, but is this likely from a person contracted by Direct Line. Note his van had no marking, but he seemed very professional in his approach and communications with me.

2) Is he correct when he warned me NEVER to jump start with this car (or any modern car), he recommended buying a Power Pack for the regular jump starting of my son's car.But a power pack is just a battery so what is the difference.

Car 2010 Focus 1.6 Petrol Titanium.

Any views

[artscot79]

1 i dont believe you were conned a short or faulty cell in the battery wont effect it till the colder weather hits also completely draining the battery can cause a cell to go faulty 2 you dont jump start the focus from another car the smart charge on the focus pumps out 18v on a flat battery which can fry the cars ecu and the ecu of the car jump starting it as they only run 14.4v max some less im sure some will say its ok ive personally seen 2 with fried ecus from jump starting you can use a battery booster to start it power packs dont have ecus and other systems in them its just a battery nothing to damage however on another car you suddenly put 18v into the system frying the ecu or blowing fuses

[Stoney871]

It's quite common for recovery companies to use locally retained garages and recovery vehicles.

All the pony thay the AA has in it's adverts about having more dedicated patrol vehicles is a load of tosh, they use more contract garages than any other (at least in the South west).

I used to be RAC and always got a marked up recovery vehicle, i'm on Green Flag now (free from bank) and they do use locals, especially in very rural areas and public holidays.

As long as you got an invoice when you paid for the battery then I wouldn't worry.

I strongly recommend a battery pack, as Arthur says far better for the car.

Something like this is suitable and inexpensive, I carry one like it in my Patrol Car and it has been used many times with no problems.-

http://www.ebay.co.uk/itm/12V-COMPACT-JUMP-START-STARTER-BOOSTER-CAR-VAN-WITH-AIR-COMPRESSOR-/160753319647?pt=UK_Recovery_Tools&hash=item256da4fedf

[pauljoanss]

I didn't get an invoice, that was a bit stupid of me.

If the car normally puts out 18V to a flat battery, why should this fry the ECU of the jumped or the jumper.

[Stoney871]

If you didn't get any invoice or receipt then I'd check with direct line that it wasn't an under the counter sale.

[artscot79]

Another point to add is, never, ever, jump start a Smart Charge vehicle with a flat battery.

The system can produce up to 18 volts, which can fry major modules.

The theory behind smart charge, is a battery will take a charges at its most efficient when it’s cold. Following start up, the PCM checks the Engine coolant temp, and intake air temp, and calculates a cold engine. It will then boost the battery charge, pulling it back as it calculates the under bonnet temp coming up. Its not there to compensate high demand as is the common misconception.

The problem comes on a jump start, when the PCM sees a cold engine, and then a poor battery condition, and can then instantly zap out about 18 volts because its trying to recover the battery. Unfortunately this sudden surge can cook modules.

most cars run at 13.8 volts mate not 18volts so add youre 18v to a jumper car and you can fry the ecu easily or pop fuses on youre car you can do the same

[ferretfloozy]

ive used a battery pack and i also have a spare battery on an optimate charger ..i'm only doing around 1000 miles a year in the focus and the alarm/immobiliser drains it so i used to use the power pack to add a little boost if it had not been used for a few weeks/months now i have a heavy duty 63ah silver calcium- its true what artscot has said about ecu etc ..my power pack is only 17ah i only use it to add a bit of extra when needed ..if it was flat then i swopped it with my spare ( fiesta battery gave up so i put spare in that and bought h/d for focus keeping focus battery as new spare)..i did read somewhere on the internet that so long as the donor car was not running and you turned your headlights on before disconnecting jump leads it was ok .. but i never tried it - always use engine as earth and not battery - dont try bump starting it either

[Preee]

You learn something new every day , i never knew any of this , Cheers Arthur.

[DaveD]

I have a battery pack just in case any of our three cars (two sons and our car) needs a jump start. Jump starting is no real bother just double check the connections before attaching leads and always earth the car to be started to an engine lifting eye or a large rust free bolt then you will be ok. battery packs dont cost a lot and are real handy. Keep them 'topped up' this time of the year by regular charging monthly and store indoors in the warm.

[ferretfloozy]

i wont give anybody a jump start using the focus either.. same damage can be done to ecu ..only takes the other driver to rev the engine when it fires up and thats you stuffed ..do you think he's going to pay for your repairs? ..but bet your life he'll blame you if his develops a fault

[pauljoanss]

From these posts, there appears to be agreement that the car supplying the jump is the one at risk, although in my case it was my car being jumped which came off worse.

Still do not understand why the smart charge is designed to put out 18 v if this can damage components, as the cars are connected in parallel then the supply car will still only see 18 v which must be within the component limits?

[ferretfloozy]

your car monitors the engine as cold and adjusts the voltage to suit gives upto you a nice healthy 18v to compensate ..then you rip off the donor battery and all that extra charge is zapped round your own car spiking the delicate components ..i think thats why its recommended you put your lights on before disconnecting the donor battery to help reduce the excess charge .. does'nt matter if your giving or receiving a jump start ..your still at risk of a spike especially if the donor car has an engine running .. a fully charged booster pack wont need any extra the power will go to car battery - 2 cars charging the same battery somethings gonna get upset

[pauljoanss]

Just reading the car manual on jump starting and there are a couple of interesting instructions.

" do not connect to neg terminal of flat battery, connect to battery connection point".

" run both cars for 3 mins before disconnecting cables"

"do not switch on headlamps when disconnecting the cables, the peak voltage could blow the bulbs"

Despite these warning notes, the manual appears to approve jump starting.

[artscot79]

yeah they do state that in the manual thats at youre own risk the qoute i made above is from petercooper car repairs who know a lot about smartcharge also ive personally seen 2 cars that have had the ecu fried from jump starting the car off another car

[Stoney871]

Totally agree, not worth the risk with the amount of electronics a car has nowadays.

Even the recovery services use booster packs.

[Steven33]

for sale: one set of jumper cables I only just bought

[Stoney871]

for sale: one set of jumper cables I only just bought

Ouch.

[Steven33]

I cant believe I never knew about this, would also have thought it would have mentioned something in the haynes manual. I know they all have a generic "how to jump start a car" section copied and pasted into every manual but you would have thought it would have been mentioned! maybe it is and I've just never read it because I didnt know it was bad to jump start fords

[artscot79]

the truth is you can jump start 10 fords and its all ok then another 2 blow the ecu theres no sure way thats why no breakdown recovery will ever jump start a car now they use booster packs

[DaveD]

Booster packs is the way to go. Throw them jump leads in the attic (copper will be worth more in the future)!