Did you look for the illumination in very low light? It's not very bright and if the area you point the meter at is above a minimal level, you won't see the illumination. Also, it's only on the far left end of the scale - the low EV numbers.
I don't believe the Spotmeter V ever took more than one battery - actually three stacked together, but the meter has been made for a long time so there may be different versions.
I've used mine for 20+ years and I don't recall every using the feature in the field. Unless you take photos consistently in very low light, I wouldn't worry about it.