Flat battery

[Teddy Lop]

Fairly new battery in wife's 2007 Forrester went flat in a few days - completely flat, no alarm as battery ran down or anything. Now reads 0.00v.

Is that likely a failure of the battery itself, as with most causes they'll generally have at least a little voltage left?

And at 0v best to assume completely fubar?

TIA.

[paintman]

Could be a number of things incl the battery.

'Fairly new' as in how old? Consider warranty return if within warranty period.

Why was the battery fitted - as in what was the issue requiring a new battery?