Thinking of a new gadget...

[Csory_imp]

GoldOxide: Display current is now limited at 20mA/segment@5V. Absolute maximum rating for the display itself would be 40mA. Once I have assembled the final version will test for required maximum brightness and adjust current accordingly - then measure what I ended up with. If your question is about connecting this to an unswitched circuit, I'd rather modify operation slightly:

(1) keep measuring battery voltage once per hour, store the result, send electronics into deep sleep mode inbetween, no display at all.
(2) when battery voltage goes above 12.7V (i.e. generator charging = engine runs) display would come up as normal, showing previously measured battery voltage, then go on as usual. This could also be triggered by pushbutton or gyro (i.e. a tap on the display or moving the handlebar a bit).

Typical power requirement would be 1mA for this setup (while the engine is not running). Self-discharge of the CB1100's SLA battery equals to about 0.8mA (11.2Ah, 5% per month).