Does not turn the start

Good afternoon if someone can tell me what
the fault can be, it is a renault 19 1.6 naphtha/cNG from time to time
when starting it, it does it, and it does not turn on the battery
is new and load well because I have a voltimeter and in a state of rest 12V brand and in operation of the engine
is in 14 and 14.8v takes it to an electrician and tells me that the donkey is fine. It happens to me on different occasions and
when the ambient temperature drops, after
8 hours stopped.
Greetings to the entire forum.

You don't have the problem on the battery, you have it in the starter engine. Well because the uploaded brushes are and do not have hardly strength to turn with which you only hear the starting relay (the CT, TAC,).
Or because it is the same start relay that is deteriorated and does not close the electrical circuit to feed the electromotor. (makes the same noise).

Be one thing or the other, you go to have to disassemble the starter from the car, and one of three, or repair it yourself, or take it to a repair workshop, or buy it new or exchange.

Greetings and if you have any questions of how it is disassembled or how it is repaired once you have it outside you have nothing more to write.

of the start is fine but in reality in cold