I'm in the UK. Car is 1.3 litre.
QUESTION (1) I know this may not be the best way of doing it but, in theory, if a car battery got flattened by leaving the headlights on then why would a fully charged second battery attached in parallel to the flat battery give almost no help at all?
It's was almost as if the second battery lost nearly all its charge to the flat battery.
Can someone explain what is happening with the battery charge please.
QUESTION (2) If that's so then, to get the car started, is it absolutely necessary to put a charger on the flat battery which is in the car?