Occasional Flat Battery

[nonsequitur]

My daughter and son-in-law's car, a FORD S MAX DIESEL AUTOMATIC 13 reg, has on several occasions been a non starter due to a flat battery.

A new battery was fitted, and the car has been in the Ford garage for three days where it was checked and given the all clear under guarrantee.

Following the garage visit, after about two weeks the battery was flat again. They do a mix of short and medium type journeys.

There is no pattern to the failures, it can happen after three days or three weeks.

It is the first time that I, or they, have come accross such a problem and several dates and appointments have been lost because of it.

Have any PH members got any ideas for a solution?

Thank you in advance for any tips or advice.

[OldGermanHeaps]

Get it checked out by someone competent. There is either a pasasitic drain, a faulty battery or charging defect, simple as that.
In the meantime buy a lithium jump start pack and keep it handy so they don't miss any appointments. They are tiny and also double up as a torch and phone laptop charger so well worth £30.

[GreenV8S]

Any competent auto electrician should be able to confirm that it's charging properly and does not have an excessive discharge when it is switched off. I assume you've had these checked, but if not then get them checked before you go any further. If those checks don't pick up any faults you might have an intermittent current drain. Look for door switches not operating correctly, radio being left on, alarm triggering repeatedly, poorly designed phone chargers etc being left plugged in.

[chammyman]

Dash display can go wonky and not let it sleep. Result dead battery.

Find someone with a flir that can monitor it