forum.cncdrive.com

Here is GeckoDrive Tech Support response:

The issue with a DC side switch is inrush current. Opening a switch is not a problem but closing one can cause very large currents for a short period of time. We recommend putting a current limiting thermistor in between the drive and the switch if you cannot avoid using a switch.

Well, in this case the problem is not the charge pump relay, but what they wrote means that if you powering up the drive using a switch to turn the power to the drives then they can damage. Strange if they think that this is OK.