[Rolling Thunder]

If you are running Nimh or Nicad batteries and dont use a regulator you and use the failsafe switch on the power expander.
If you are using a Turbo Regulator, it also has a failsafe switch and charge jacks. So you wouldn't use the switch on the power expander you would use the switch on the turbo regulator.
You can also use a seperate switch if you want. You would just install it inline between the battery and regulator.

I use the pin switch into the turbo regulator. When you pull the pin it turns on the Turbo Reg.