Comments on: what is the least or worst than can happen when car battery cables are loose?

By: george d

george d — Fri, 20 Nov 2009 15:29:58 +0000

One thing that has not been mentioned in any of the answers is that if an electrical connection is not solidly made it can result in a massive build up of heat at the ‘point’ of connection due to ‘arcing’. If this happens under starting conditions – heavy load- it can result in excess hydrogen gas being given off from the battery resulting in an explosion.(Seen it at first hand) As for the posters saying that you can run a car on just the alternator- incorrect you will burn that out in a few seconds.

By: Joseph

Joseph — Fri, 20 Nov 2009 15:29:58 +0000

the pos side could of hit the ground and burnt out the alternator and wiring harness

By: Former Level 7 Top Contributor

Former Level 7 Top Contributor — Fri, 20 Nov 2009 15:29:58 +0000

If the charging system was working properly it would have no affect if the leads came off when the car was running. If it had slid and made contact with metal it would have shorted the battery. Loose terminal ends could keep the car from starting, or keep the battery from charging.

By: John Reid

John Reid — Fri, 20 Nov 2009 15:29:58 +0000

Probably nothing would have happened. A lot of cars will run with no battery if the engine is already running.
After you stop somewhere, the car would not start again until you replace the loose cable.

By: mellowfellow

mellowfellow — Fri, 20 Nov 2009 15:29:58 +0000

well , that does sort of sound like a typical kind of thing to happen..Theres nothing quite like doing the job properly yourself which luckily for you , you had the common sense to do.`Well Done’.
Really the worst i can think that could have resulted would probably be that as once the car has been started ,the battery more or less becomes obsolite , until its asked to do a reasonable job to do like re-starting ( which in your case it probably wouldnt have done), as it needs a good mechanical conection to make a good electrical connection, So it may well have just basically refused to turn the engine over resuting in you getting stuck.This for most would have meant caling out the emergency brakedown services and footing a bill plus inconvenience !!.
Other than that there could have been a very remote chance of the battery being so loose causing a very small Arc or jump of sparks whilst running ,as it would be continuously be asking to be charged by the alternator. Of course this now may well be the worst scenario as if there could have been a petrol leak under the bonnet for example , though unlikely , it may have been enough to cause the car to catch fire .
I personally wouldnt have been very happy either as this not long ago , happened sinilarly to my mum.

By: Macy

Macy — Fri, 20 Nov 2009 15:29:58 +0000

A classic example of ignorance from Halfords. I bought a new battery for my car from Halfords but I fitted and connected it myself. My dad is an electrician and I knew from watching him for years how to do it.
You should go back to Halfords and tell the manager about the battery and the guy who fitted it….he’ll either be fired or get a telling off and will hopefully learn from that mistake.
If the positive and negative cables ever touched while the engine is running then there would be a large spark and your engine would probably cut out. I say probably because its never happened to me but the spark might ignite a fire so you should stop anyway.
I can’t understand where the guy from Halfords went wrong, connecting a new battery is easy. Connecting a supply to the car whilst the battery is disconnected is a bit more difficult. You can’t just take a battery out otherwise the alarm will sound when you reconnect the new one and the radio will think its being stolen so you have to enter the anti thief code.
You should learn how to do it yourself, you can never trust these people.

By: Kev P

Kev P — Fri, 20 Nov 2009 15:29:58 +0000

As has been said, usually a loose lead would not be a big problem; BUT>

If your mum was on her own and turned off the engine somewhere remote, she wouldn’t get it started again without tools/knowledge and would be stranded.

It could have started a fire (small chance, but hey, you’re complaining:))

It could have shorted out the electrical systems on your car (VERY expensive depending what burns out)

Halfords seem to have a 1-day training scheme for their "mechanics". I bought a £200 stereo from them once and feeling lazy, asked them for the free fitting service. On seeing that my car had wires ready for a radio, but no multi-plugs to identify them, they refused. Turns out "fitting" for Halfords means "plugging in". I fitted it myself in 15 mins using trial, error and common sense. Halfords is increasingly a good place for cyclists but a last resort for motorists.

Well done on getting the spanners out and getting your mum home ok:)