GPS on 6v bike

[Greybeard]

I've found a way of using my GPS on the, (6v) Beeza. I've bought one of these power packs:
https://www.amazon.co.uk/gp/product/B00XTXY0JW/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I've also got one of these waterproof GPS cases that fits on the handlebar:
http://www.ebay.co.uk/itm/400603291745?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
The touch screen works fine through the plastic window

There is not room for the battery pack and GPS together in that case so I've got a long charging USB lead and I plan to put the power pack in my pocket to begin with but I may fit it into the toolbox with a waterproof cable gland later.

Unfortunately The Garmin Nuvi 3597LM doesn't have an earphone socket and I don't think its Bluetooth will work with a BT earpiece; it would be very useful to hear the voice.

[muskrat]

Do they make them with a Pommy accent? The Aussi one works in beers rater than miles "In one beer hanga left"
Their good for checking your speed as well. Not that I worry about things like that
Cheers