Why would I (or anyone) care "which" cell of a battery is low, or for that matter, if any cell is low ?
Is it like I'm going to go to work and overhaul that one cell ??.
I guess at my age, I remember the old days when batt hydros were some what useful, long before todays accurate voltmeters, and smart chargers, I'd guess I traded my useless hydro for a converter that maintains batteries like they are supposed to be, to the point of making a batt hydro completely obsolete..
But if a person is still green at camping and maintaining batteries w/ todays suffistigated smart chargers, then you would not know that they made the battery hydrometer obsolete long ago. Give your smart converter some time, and it will show you just how long it can make batteries last, and how obsolete a battery hydro really is.
And niner, how did my gauge wiring ever get entered into this discussion ??
Maybe you need to get a life ??