Dear IPACS,
I recently discovered that in a320neo we can discharge the battery is this was available before from when ? And doing that I discharged battery to 22.0 volts but on that voltage the Apu should not start but it start is that is not coded (external power was off) and when I hit 22 volts on the battery all the lights of the cockpit was turn off even there was no light on external power and external power was not available after drop of 22 volt so I started the Apu and then the lights came but there was while starting the Apu there were not lights on master switch and st switch of apu only electric power was available to radio and on bat pannel above IRS aslo some ecam waring appear .