Car won't start

[richybigman]

I have a R reg saxo vtr but in the cold it won't start, the battery just seems flat, once i put my booster pack on the battery it starts and runs fine. I've had the alternator tested by halfords and they say it's giving out the right amperage, what else could it be? I have replaced the battery recently.

[KebabMeister]

You could have a faulty replacement battery.  It might be worth having it checked over again.

However, your car might be suffering a voltage leak/drain.  This means something is using the battery power when you're away from the car and draining the battery.  You need to check the most obvious things such as courtesy light, normal lights etc. being left on.  In some cases it could be your radio or an alarm fault.

Do you have access to a volt/ampmeter?

[JackRegan]

One thing that can cause this problem in the cold is a faulty starter motor.In the cold the starter motor can become stiff and is difficult to turn....putting your booster pack on gives the starter extra available current and it turns....i have had this happen before and when i changed the starter motor i never had a problem again even in the freezing cold.Good luck and hope you solve you problem.

[landie]

There is a device called a 'Rectifier' somewhere in your system which converts alternating current, produced by your alternator, to direct current which is needed to charge the battery. It may be a good idea to get this checked. 

[richybigman]

Thanks for your answers, i have had the alternator and battery tested and both are fine, i have rewired my stereo which was ok as far as i could see anyway. i have bought a starter motor but not got round to fitting it yet i hope that will be the answer. Only thing after that is my alarm which was fitted by sextons so i assume that it will be ok. I'll let you know if the starter motor works