Dead Battery

arcon5

Jump starting is a mugs game, it's so unbelievably dangerous, your actually safer rewiring a mains socket with the power turned on, because one slip and you've got a car battery kicking out over 400 Amps without a fuse to stop it, hydrogen gas is then inevitable, sparking is also inevitable and if that gas ignites, then hot battery acid will quite happily eat through anything it touches.

And how many people have ever died or been injured jump starting a car?
And how many cars are jump started daily?

Even recovering agents are happy jump starting cars and the consumer rights board certainly isn't littered with people complaining their car has been fried or the recovery guy lies dead on their driveway or on the side of the m25.

Last time I called a guy out he had special leads built in to his truck rather than having to lift his bonnet and its not unheard off!


Your being overly dramatic and not at all money saving.

Rolandtheroadie

Before I buy anything for a car or bike I find out whats really wrong with it first.

Buy a cheap test meter(normally about £3 every now and then from aldi/lidl) and it'll pay you back time and again.

I'd also be looking at the altenator here (looking at, NOT rushing out to get another one).

If that was ok id be loking for something draining the battery.

Then checking the battery voltage after it had been left overnight.

Sure you might end up needing a battery, but you might not.

Uniscots97

This is my current car, it's just through a few things it's not been used that often

Uniscots97

Does anyone know how long I would need to leave it before I can start the car (and it doesn't do what it did yesterday, which was cut out as soon as the donor car was unhooked, please bear in mind that I didn't leave my car anytime at all before starting it)?

Paul_the_Painter

With regards to removing a battery whilst the engine is running, I've done it myself and is apparently common practice is garages dealing with cars where people have lost their radio codes etc.
Not going to recommend it to anyone, but it shows that if the jump leads come off and the engine stops, your problem is not likely to be with the battery, as the car will run quite happily with no battery at all.
I think your problem may well lie with the alternator not the battery, charging the battery fully with a battery charger will mask this by the car running on the battery only without actually being charged by the alternator.

IamNotAllowedToUseMyName

Any recent car with immobilisers or the like will drain the battery in a few weeks.

The original poster's problem is quite simple - they have not understood that jump starting does not charge the battery. They not only need to jump start, but they need to charge it, either by driving around for a long time (hours rather than minutes) or using a cheap charger.

Modern cars may get upset by being jump started or having flat batteries.

Also, a flat battery may be damaged, but actually it is not a given. We had a car sitting with a permanently flatting battery for a year, but when we had it tested it was about 95% of full ability and once the car was being used properly it was totally reliable.

So at the moment, simply get the thing properly charged.

[Deleted User]

Not directly related to the problem the OP has right now, but for anyone who regularly leaves a car unused for weeks/months, one of these isn't a bad idea.

TrickyWicky

Uniscots97 wrote: »

Does anyone know how long I would need to leave it before I can start the car (and it doesn't do what it did yesterday, which was cut out as soon as the donor car was unhooked, please bear in mind that I didn't leave my car anytime at all before starting it)?

You should not need to leave it at all - I mentioned this yesterday.

As long as your car can draw current from any power source (in this case your donor car) it will let your car start instantly. Your car should then continue to run from the power from it's own alternator when you remove the jump leads. If it does not then your alternator is knackered as someone else pointed out.

You may also still have a duff battery too which won't help. Jump start the car, leave it running for 10 minutes to recharge it's own battery, turn off and then try to restart. If it doesn't restart then your battery and / or alternator are faulty.

TrickyWicky

kaya wrote: »

You lot are hopeless, the first thing is to find out what is destroying or draining the battery

IF the battery is already knackered then there is no fault to find. The op needs to determine if the car will continue running once the jump leads are disconnected and also if the alternator is working.

You're making an assumption that something is shorting and flattening the battery and it may not be.

kaya wrote: »

I could fit a new battery to my car and leave it for 3 or 4 months and it would still start

Depends what type of car it is and what time of year it is. In the colder months no you could not do what you claim. Also as mentioned, many cars have devices running 24/7 which draw current.

kaya wrote: »

some common sense before spending out on yet another battery

Yes I agree hence my comments about the battery and alternator before spending out £Mega on an auto electrician. Common sense?

Strider590

Mankysteve wrote: »

Never such be in my life.
1. Modern batteries are sealed units so no hydrogen gas

Really? I've got a photo somewhere that proves that theory very wrong indeed.