I find that I can read the battery voltage from the two outside poles of the battery at anytime whether switched on or off (??). I can't quite figure this out. It's the same on the single mode and dual mode batteries.
In your review I believe you said that there is no voltage at the poles when the battery is switched off. I don't think that is correct. The battery could be shorted  even while switched off.
I don't recall.. If so, I could have been wrong.
I definitely do not remember measuring voltage on the battery... my presumptions are only based on whether the LED would lite or not.
I could not switch the battery off I had.. I only had high and low and there was a tiny switch that turned the LED on or off.
The version I had was before the single and dual mode batteries I believe..with mine it was 28W setting or the 35W setting and that tiny switch for the LED.