Alfa 156 2.4 jtd flat battery
Haven't used my car for at least a week. Tried to start it and it won't turn over. Get what I assume are the usual warnings, as the thing does not have enough power for the system.
It's an original alfa battery (just under 9 years old), with the viewing window. This shows white - which is supposed to mean electrolyte is low.
However I've been told it can mean the charge is low, that I should test the alternator and if this is fine, then the likelihood is the battery is knackered.
Can the battery top up? If so, how? And with what - distilled water was my assumption on the basis that there should have been no leakage of the original fluids. Or is it a case of it being terminal. It's been jump started and is at garage, who have said that they will charge and test (and then tell me it's knackered?), but that usually white = dead (ie preparing me for the earlier bracket).
Thanks for your help.