A 1A wall adaptor is too low for true 5v vaping. The Kensignton is marginal and won't keep up to a 510 or a 401. You require between 1.4a to just over 2.0a depending on which model atomizer (resistance varies significantly between models and brands) you are running.
I think the basic problem with all these discussions is that we all try to rate the devices in terms of voltage. There can be a world of difference between different 5 volt devices. We should really be talking in terms of power. For instance...a simple 5v device with 2 bats will provide 6.9w of power for a 3.6ohm 801 atomizer but has to crank out 9.3w of power just by switching to a 2.7ohm 510 atomizer. Both are still 5v vaping, but there is a significant difference in the amount of power being drawn from the battery.
As a result, current sag from battery sources will be higher when using 510 atomizers than with say a 801 which typically has much higher resistance. Multiple bats or larger bats will reduce this effect.
I think the basic problem with all these discussions is that we all try to rate the devices in terms of voltage. There can be a world of difference between different 5 volt devices. We should really be talking in terms of power. For instance...a simple 5v device with 2 bats will provide 6.9w of power for a 3.6ohm 801 atomizer but has to crank out 9.3w of power just by switching to a 2.7ohm 510 atomizer. Both are still 5v vaping, but there is a significant difference in the amount of power being drawn from the battery.
As a result, current sag from battery sources will be higher when using 510 atomizers than with say a 801 which typically has much higher resistance. Multiple bats or larger bats will reduce this effect.