Car Bettery 9.4v Wont Start

[cefiro]

had issues with starting my car this morning, just ticked very quickly and looked at the PFC commander and battery said 9.4, cleaned terminals = no diff. Got some people to push start my car and got it home. turned car off and started fine again. I then went for a drive and looked at the voltage 16.6V. turned the car off and looked at the voltage again and it was 14.4V. Anyone got any ideas of whats happening with it. I have never noticed this before. i dont think its ever done this before as now the windscreen wiper are at light speed and the same with the power windows.

Edited October 3, 2009 by cefiro

[blind_elk]

I think your alternator is cactus. And the fact that it is overcharging the battery suggests that the battery will be dead soon, too.

[The Dan]

Keep driving the car like that if you want to melt your ECU, coilpacks, etc...etc...

[steve12]

Get the regulator replaced. The battery may also be damaged but you may get away without changing it. Best to not drive car until problem fixed.

Alternator can output up to 30V and do a lot of damage. The low impedance of the battery will hold this down a bit.

Not sure what PFC is and how accurate it is. Suggest using multimeter check at the battery. Battery charges at 14v and sits at around 13v when not.

[blur]

Possible open circuit battery, can cause high charge rates like this. Best to get the battery and alternator checked before you damage something.

[benl1981]

Get it checked but you may be able to replace just the voltage regulator part of the alternator if thats the problem. Usually cheaper than getting a "recod" alternator which is Usually just new brushes and spray paint..

Edited October 3, 2009 by benl1981

[mad082]

i'd say that the battery has dropped a cell (hence why it is reading at 9v) and this may possibly be the cause of the high voltage when driving, or the voltage regulator is shot and that has shagged the battery.

[Jmaac]

+1 for the regulator. Easy to change depending on type, usually little black box on back. As steve said just double check with a Multimeter

Thats a service. Recond. alternators are usually rewound also.

[cefiro]

Cheers its dropped over the last few days down to 14.4V or around there. going to take it to auto electrician today/tomorrow and see have seen it into the 15V but seems to settle down. its either the battery or alt regulator anyhow will let you know in case people suffer the same prob.

Cheers for the help