Cold start problem

[Petrolsmasher]

Replaced partners battery as it was really slow to crank when cold and didnt stop once or twice, battery from halfords.

Suddenly worked perfectly and started instantly in the cold.

2 months down the line - nowhere near as bad but starting to slowly crank when cold again, when cars warm its fine so im thinking not alternator.

Im thinking possibly battery and will get them to check but seems odd when its so new, anything else if the battery test comes back okay?

[paintman]

Check the battery terminals are clean & tight.

Is the car being used mainly for short journeys with a lot of electrics on - lights, heater fan etc? This could be running the battery down & the alternator isn't putting enough in to keep it topped up.

Get the alternator checked - you can't just assume it's not the problem.

[Petrolsmasher]

paintman said:

Check the battery terminals are clean & tight.

Is the car being used mainly for short journeys with a lot of electrics on - lights, heater fan etc? This could be running the battery down & the alternator isn't putting enough in to keep it topped up.

Get the alternator checked - you can't just assume it's not the problem.

But once its been started once in the day it works fine for the rest of the day even doing lots of stop start.

[GreenV8S]

Don't guess - do an electrical test to see whether the starter motor is receiving the proper voltage, and if not whether that's because the battery isn't maintaining a sufficient voltage under load or whether there is a voltage drop in the circuit.

If the battery isn't holding up, you then need to find whether it is fully charged and do a load test to see whether it can carry the normal load.