General Fiat 500c not starting unless jumped - have replaced carplay and disconnected blue&me, any other ideas of what it could be?

[charlillie]

Super frustrating and have had it looked at by various mechanics but no one can figure out … any ideas?
- blue&me disconnected
- has been re-alligned with the thing you plug into computer
- battery charges when plugged into a mains and lasts for 3 days
- i can go for a massive drive (5+ hours) and it will still not work next time I try
- 2015 plate

 

[John202020]

New battery? What do you mean lasts 3 days, should be able to sit weeks unused and still start.
Has the infamous engine earth strap been replaced?

 

[charlillie]

New battery? What do you mean lasts 3 days, should be able to sit weeks unused and still start.
Has the infamous engine earth strap been replaced?

Hey John!

I know, that’s the problem! If charged at garage it lasts three days to turn on and off otherwise I have to jump it, it has and still playing up, at the garage again today but losing my mind with ut

 

[John202020]

So are you saying it starts normally then after 3 days or so it won't?
Is it being driven in those days?
Tempted to say alternator( my dad's alternator failed last month, no warning lights)
Engine earth strap is a must if it's not been done, first.

 

[steveras57]

Hi can you get somebody with a multi-meter to check if its getting charging voltage from the alternator(should be 13.8 to 14.5)- its not impossible for the warning light to stay off! even if the battery is NOT receiving the correct voltage to maintain the battery!

 

[John202020]

Whilst testing voltage also try with and without a jump lead from a good earth point on the engine and the battery NEGATIVE?