Do I need new battery?

[v4rley]

So... I'll keep it simple.

 If the car is left to stand for 2-3 days it won't start, although all electronics still work ie stereo, lights, windows. Polar shows 11.5v ish

Jump start the car and shows 14.1v

If I do some vcds work or general tinkering for say 30mins the battery will be at the same state as sitting for the 2-3 days

Investigations I have done:
Tested battery draw in series,
First minute: 0.90a
Next 25mins: 0.14a
Then on: 0.02a

I have take for a basic battery check at halfords and local garage and both say something running, but surly this is the car shutting down for the first 30mins?

Battery is Bosch S5 and 4 years old. And just test now with multimeter after shut down and is at 12.3V

Any help would be greatly appreciated 

[Andy]

Have you changed your car stereo

[th3_f15t]

Another test would be to borrow a compatible battery from somewhere and run it for a few days doing the same tests. Least that way you can isolate what's at fault (battery or car electronics).

[v4rley]

Have you changed your car stereo

Has a rns-510 fitted before my ownership and has eddies gateway, and since seen by Eddie

Another test would be to borrow a compatible battery from somewhere and run it for a few days doing the same tests. Least that way you can isolate what's at fault (battery or car electronics).

Yes suppose this would be a good option, although I think my crappy fiat run-about is a lower grade battery but maybe worth a try.

[Andy]

Change the battery is its 4years old hopefully that's is what is causing the issue

[v4rley]

Yeah probably the way to rule it in or out, was hoping to get a replacement from halfords as the S5 still has year of warranty left, but their testers don't seem to allow for the close down procedure of the car and as mention say there is a draw on it.

[doylebros]

For my money it's the battery.

To prove it disconnect it for the three days or your know period to failure then reconnect it - which will rule out any current draw which may happen after an unspecified time - if it's starts recheck the current draw issue but as above my money is on your battery as your testing and values are as expected of a health vehicles electrical system.

[v4rley]

Ok thanks @doylebros.

Was discussing with the wife earlier, thing is she pretty much uses the car most days so bit of a tricky one to test, and only occasionally get caught out by its when she hasn't used it. But we're away next month so will give it a test then whilst not being used.

Also feel it's the battery due to it not being able to deal with me doing tinkering / vcds work etc.

Thanks formal your advice guy will keep update with progress