# Garmin 640 Battery Issues



## kbkeys1 (Aug 11, 2014)

Just bought unit, happy with GPS functions, G2 Vision upgrade, and screen. However, battery life was only 3hours before low battery warning message came on( was fully charged). Manual says 11 hours between charges! Put in fully charged spare that went 4 hours before message. Advice please, thanks.


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## GSSF (May 25, 2013)

I have a 640 and like it as well.  Good unit.  I can get a solid 5+ hours out of mine off a full charge no problem. That is with the screen on the brightest setting and me constantly panning and zooming so that eats the battery.  If you leave It alone and back the brightness back to 50% you could get more out of it for sure.  Although I think 11 hours is an exaggeration you should be able to do 5 easily.  I'd call garmin and see what they say if you're that buggered by it.


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## DuckNut (Apr 3, 2009)

Is it possible to turn down the refresh rate of the gps from 3 times a second to every 10-15 seconds?

I carry a handheld with me at various times and it would die in just a few hours so I lengthened the refresh and now those three little batteries go days before needing replacing.


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## timemachine (Sep 1, 2014)

Why not use an external battery?  If you don't want to use the boat battery, you could get a battery pack with more cells for not big money.  

Plus, don't forget the dielectric grease on the connectors!  Rust never sleeps.


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## kbkeys1 (Aug 11, 2014)

Thanks for the help.


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