They use to work that way back in the 1960's and 1970's, buy nowadays with computers and such, what they indicate depends on what the manufacturer wants it to do... some are essentially just voltage monitors.

Thanks. I'll need to get a new battery this time around.

I live in a condo so getting a trickle charger and leaving it for months when I'm away or using a battery charger isn't too easy. There's no power outlet in the parking lot basement.

Oh, then...

What you need is a good and trusted friend* who will gladly come over to your place and give your X5 a nice airing** every week or so while you are away.

Funf Dreisig

* AKA one of the wacko members of this forum
** AKA "drive it like it was stolen"