hi i have a petrol focus and the bateries dont last any one have a idea why it is doing this

or where i should start looking?

 

You getting the proper silver calcium batteries?

 

check electrics - you might have a problem with an alternator or any other thing - and the battery is simply not charged properly when driving

 

as said before make sure the bats are silver calcium because if there not the smart charge alternator wont know what its doing, if you are using the correct bat you will need to get the smart charge system checked and reset, and a word of warning you should never jump start any new ford as these systems can go upto 18v
hope this helps rich

 

What do you mean by blowing batteries?

 

how do i know if its one of those?

 

sounds like over charging alternator dont know ho to check but there will be spikes in the volts that blow the battery and if so its a new regulator easy fix tho quite simple to replace but try the right battery first

 

tested alternator its charging at 14.5 volts

?