Different Voltage Battery?

I know the golden rule is that you shouldn't use a battery of a different voltage. However, if there are two laptops with what seems to be identical motherboard and power supply pinouts, could it be possible to use a higher voltage battery in one that comes with a lower voltage with possibly logic on the mainboard that would detect the voltage difference and work accordingly? Maybe wishful thinking?

One is 11.25V the other is 15.2V. I know, a significant difference, but the 11.25V is 30Wh...

Different Voltage Battery?