jackrae:
If you are concerned about 4.85 volts from a 6 volt battery not being enough then you need to reconsider your understanding about battery abuse. At that voltage the battery is well on its way to that great battery store in the sky.What current does the laser draw and what capacity of battery are you using. In other words battery duration is based upon AH capacity and load current.
I take it you appreciate that a 12V 5AH battery will last no longer than a 6V 5AH battery in your application.
Sorry I do not understand what u mean by the battery is well on its way to the store in the sky?
And the laser is a 200mW laser so it draws 0.066 amps. Or 66milliamps