F75 when do you change your batteries?

[Roland58]

On my F75, I changed my first set of batteries when the three part scale had lost the top third and using it for quite a while after that, but, before it lost the middle third. At what point do you change your batteries? Top third gone? Middle third? or Last third? Will the machine operate at full efficiency until the batteries are dead? Is there a warning before it quits?
The batteries seem to last a very long time. I have noticed that using the pinpointer will make the top third disappear if the batteries are on their way down, but, it comes back when the pinpointer is turned off. I guess the pinpointer feature uses more power. Also, I have hunted for a while with the top third missing, quit for the day and went out the next day with the top third back again for hours before going away again. I knew the alkalines would self-recharge to a small degree, but, this was surprising.

[Sandman]

You would have more answers to your post if you put it in the Fisher Research Labs section as JW Fisher is a Pulse Induction forum. But to answer your battery question, Alkaline batteries give the detector full power till they really get pretty low. Rechargables now just test great and then plain stop the detector from operating. Not good when you left the spares back at the car. Seems Fisher has always been real good with batteries. My 1280's would last all summer it seemed, but now I hardly use Fisher's anymore.

[Roland58]

You would have more answers to your post if you put it in the Fisher Research Labs section as JW Fisher is a Pulse Induction forum. But to answer your battery question, Alkaline batteries give the detector full power till they really get pretty low. Rechargables now just test great and then plain stop the detector from operating. Not good when you left the spares back at the car. Seems Fisher has always been real good with batteries. My 1280's would last all summer it seemed, but now I hardly use Fisher's anymore.

Thank you for your reply, I will move the question. I knew about the rechargeables going downhill rapidly and the alkalines slowly, just didn't know if the lower battery readings would affect efficiency and when. Please excuse the "newb" mistake.

[Sandman]

Don't worry, I am a newbie with text messaging to my grand kids.