Switching from 4 cell to 3 cell?

[TwistedVegan]

I'm working on a mod that can switch easily from a 4 cell mod to a 3 cell mod by bridging the contacts for the 4th cell. 

Does anyone know what would happen if someone forgot to load the 4 cell profile before using 4 cells or tried to use 3 cells with the 4 cell profile still loaded? The design makes it impossible to put the 4th cell in with the contacts bridged so no risk of a hard short. 

I'm guessing 3 cells in a 4 cell profile will give a low voltage warning but what about the other way round? 

[VapingBad]

Not tried it, but I think you guess correctly.  As I understand it this setting is mainly for charging and battery protection and the device will always use all cells in series.  If you are charging externally you could set the battery type to power supply but you would lose low battery protection.  3 cells  sounds like the best way IMO, I think it would still individually monitor each of the 3 cells for low voltage, again if you are not going to charge 4 cells in the mod.  Disclaimer: I have not tried these so only do so at your own risk and if you understand what you are doing.