Can anyone help?

I have a 2013 Focus. For a long time my stop start hasn't worked (it would work after a long journey for a while but has given up completely now), I can live with that but now the alarm has started triggering randomly. It happens when I've locked the car after just using it. It will sound a few times before eventually giving up until it is used again then the same thing repeats.

On the phone Ford said the start stop is affected by the battery but it shouldn't trigger the alarm unless it's really bad but the fact that I've never needed to jump start the car didn't sound like it was a battery issue.

I know I can book it in for a diagnostic but just wondered if anyone has had this problem and found that actually just replacing the battery rectified it?

Many thanks

A new battery will usually solve many 'random' faults, my previous car. a C class Merc lit up like a Christmas tree with loads of random errors - new battery cured all. Have experienced the same with other cars too. A symptom of modern cars that rely heavily on a good voltage supply... (In the olden days, your lights would go dim, and it wouldn't start LOL)

I would agree with Stephen that a new battery will usually solve many 'random' faults. 

Back in January my 2012 Focus started playing up giving me the following 2 errors: Hill Start Assist not available and Tyre Pressure System Malfunction - Service required (a quick internet search mentioned this may be related to ABS sensor faults) This behaviour continued for a few days then whilst driving to work one morning the interior lights flashed, the nearside front xenon bulb went off and a fault warning to this effect appeared on the dash (I could clearly see the bulb had gone out in the reflection off the van in front), upon arriving at work I scrolled to the system check menu and it had stored the bulb fault.

Looking online during my lunchbreak at the cost of a replacement bulb nearly brought tears to my eyes (especially as they were recommended to be replaced in pairs!!).  When starting the car up to return home that evening it looked brighter so I got out the car to look and the bulb was working again, the system check menu was also clear. 

Plugged in a code reader the next evening and it showed DTCs in the BCM, PSCM, PAM and ABS modules. Battery voltage was showing as 11.4V and charge was 63% at engine off, voltage increased to 15v when engine on but charge remained between 60-70% over the next couple of days. Usual round trip to work is 30 miles, about 70% motorway 15% dual carriageway so it gets a reasonable run.

There was also 2 instances within this time when I pressed the start/stop button and instead of just the engine stopping the whole car just died electrically, nothing would work and couldn't even lock it - it took about 5 mins to come back to life the first time and over 30 mins the second time.

Anyway, the battery was replaced and car has been fine since then.  Looked at the old battery when it was removed and it was dated July 2012 so it was the original factory fitted one, I guess 7.5 years was quite a good lifespan.

I Also have a 63 titanium x focus. The start/stop was very intermittent and would work after a long run. Then I was warned by Ford during a yearly service that the battery was only 50 % capacity. Charged up using a ctec intelligent charger and all was ok for a few months. This month moved car about 2 yards to wash it and it wouldn't restart. Recharged to move back and  then purchased  a new Varta EFB battery ( As per original spec) All is now well and stop/start works every time