24hrs using a Garmin 800?

[gibbo]

Just starting to put together some prospective ride details which will last ~24 hrs. I have an Edge 800 and want to use the mapping/ directions feature during the ride and am aware that the power won't last that long. So, a few questions:

1. What external power supply will be adequate to cover 24hrs eg 10,000mAh? (some of the ride will require the backlight to be on)
2. Is it best to plug the power in for the duration of the ride or only when Garmin battery is getting low?
3. I've been given gpx files (x5 separate segments) for the route. Is this the best method or should I make 1 complete route?

Any other advice would be appreciated.

TIA,
Gibbo.

[Veloman]

Gibbo

Look at previous threads on Edge 800 for lots of information on this topic.

In short:

1. 10,000mAh more than adequate even with backlight on and is just what I used when riding through the night on Flatlands 600.  You could go smaller, but always better to have 'juice' to spare IMO, especially as cost differences are minimal.

2. Best to plug in from start and totally deplete external supply first.  This appears to be standard operational procedure for external power supplies.

3. Your choice and I've used both systems.  Key thing is to ensure files are sensibly named so you know which one to use!  On last 600 I had 2 files: one for going north, one for going south.  Worked well.

Other advice:

1. Save a copy of routes on the SD card.  If you have problems with 800 and it deletes internal files (Garmin memory) you will have external back-up copy on SD card.  essential IMO.

2. Save all data and switch device off/on before 350km as Garmin is subject to 'white screen of death' and this has been well documented in GPS threads under Edge 800.  There is an advantage to saving after each control unless you operate on cumulative distances.

3. Always carry a paper copy of the route!

[Feanor]

10,000mAh is over-sized for 24 hrs.

I use one of these:
http://www.amazon.co.uk/gp/product/B005VBNW2G

5200mAh runs the thing for 24 hrs with the backlight on all night, running navigation and recording tracklog.  After 24hrs the external pack is down to just under half full, with the internal battery still 100%.

I'd advise having it plugged in from the start.

Regarding the gpx files: I'd never just dump someone else's gpx files onto my device.
I'd always load them up in Mapsource and inspect them.
I expect they contain tracks, not routes.
The reason there are 5 is probably to overcome the trackpoint limitation on older models.
I'd splice them together into a single Track personally.

I'd also create my own Route to overlay the Track, and use both on the device together, but that's just personal preference.

ETA: yes, I agree about re-setting every 200k or so.
Don't let it record more than about 350k before resetting, or there's a reasonable chance it will crash.
To re-set it, simply watch as 200k clocks round.
Hit 'stop' to stop recording.
Press-and-hold for 4 seconds to re-set.
Start the timer again.

[gibbo]

Thanks for the good info.

Re. tracks vs routes. I've never understood what the difference is and why I should use tracks (as intimated in your message below).

[Feanor]

A 'Track' is a dumb breadcrumb trail, like drawing on a map with a highlighter pen.
It will have a 'trackpoint' every few metres.   You just follow it 'by eye'.

A Route is a smaller series of 'routepoints', which the machine will navigate between, giving you turn-by-turn instructions.   Downside is that the device makes routing decisions between the routepoints, and may lead you astray if the route is not adequately constrained with routepoints.

There is a fair amount of overlap in the functionality nowadays.
The Edge 800 can navigate a track, but without the turn-by-turn instructions.

My preference is to have both.
I navigate the Route to get turn-by-turn directions and zoomed in junction displays.
But I set the track to simply display in the background, so I can see if the route has gone wonky.

[contango]

Further to what Feanor said, depending on what maps you have in your unit you may or may not get useful routing instructions.

I use a rather old copy of OpenStreetMap maps and have found its routing algorithms to be - er - interesting. It's far from rare for it to take the most spectacularly scenic routes - one classic was when I was a mile from home (and the route was "follow road for 0.9 miles, turn right, destination in 0.1 mile") and it produced a wonderfully scenic 6.5 mile route that took in most of the busier local roads. Sometimes for good measure it decided that it would be a Good Thing to get off the "busy road", so it told me to turn right across the traffic, follow on a parallel road for half a mile, then turn right across the traffic again to rejoin this road. The road in question was moderately busy, with a 30mph speed limit and a cycle lane. Go figure...

If you're going to use the route as a guide check beforehand what your unit will do if it has to keep recalculating. I've found my Montana will recalculate three or four times, then give up and shut down. It will restart easily enough but if you've zoned out and are just waiting for the next beep you could have more rerouting to do.

[andrew_s]

I use a rather old copy of OpenStreetMap maps and have found its routing algorithms to be - er - interesting./quote]
It's a feature of OpenStreetMap that the map data is editable by anyone, even novices, and there may therefore be data errors such as side roads that get within a few centimetres of the main road, but don't actually connect. Garmin's routing algorithms won't take you over a gap, so you get sent round the long way.
Further to that, some creators of Garmin OSM maps will fiddle with the routing data in the map to get more "cycle-friendly" routes, so as well as things like preferring any NCN, no matter how muddy, to a road, the routing controls such as "avoid highways" may mean something different.

It's generally easier to predict how a Garmin will take you between route points with Garmin's City Navigator data than it is with OpenStreetMap data.

[gibbo]

10,000mAh is over-sized for 24 hrs.

I use one of these:
http://www.amazon.co.uk/gp/product/B005VBNW2G

Thanks for the heads-up - have ordered one and will try it out although I can see it disappearing once my kids know they can use it on their Ipods on long car journeys