batteries

Eh? No that would be silly. Brian

Logically it would be from part way up (unless completely discharged) to top.

Well you can top up the battery as a phrase and you can have a lager top shandy, which I think means the last 10% is lemonade added to the top. And "bottoms up" which usually means drink up, which could be drink "down the hatch" as that's the dirction it travels in due to gravity.

Would this be in a scientific or idiomatic context?

I think there are two drinks there:- Lager shandy - approx 50:50 larger:lemonade Lager top - nearly a full pint of lager with a (customer defined) splash of lemonade.

When I were a lad, and before I discover real ale, larger and lime (just a splash of line cordial) used to be popular but I don't recall seeing that being served for in a long time in a pub.

Yes I remmeber that, I tried it but never really liked it, my favourite was snakebite and black or a hairy chest (PiLs lager, vodka and blackcurrent). I had a week or so of liking what I was told was called black & tan which was guiness and cider.