The problem I have is on long trips (via bicycle or on foot) my phone’s battery hits 15% remaining and screen dims, which is essentially blank in daylight when navigating. I’m in airplane mode with wifi also disabled. So the only power consumers are the screen and the GPS receiver. Yet I’m still forced to power down, swap batteries, lose the clock time (which GPS strangely fails to correct), and wait to reacquire a GPS signal. Then OSMand remembers the route parameters but forgets the route (a bug).
Big hassle. I see 3 fixes:
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Repurpose an old phone to receive the GPS signal and feed the lat/long over bluetooth to your navigation phone. Since a bluetooth radio in receive mode consumes around ⅒ the energy of a GPS receiver, the main phone battery will last much longer. The GPS phone need not power a screen, so it can obviously run quite long if it’s only powering GPS chips and bluetooth in tx mode.
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Attach an external USB battery. I reject this because I don’t want to strap another box to my arm and run a cable into my water resistant phone strap.
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Get an Android-compatible phone with a dual mode LCD, so a low-power e-Ink mode can be used in daylight. I reject this because I boycott Russia and IIRC only Russia has phones with dual mode displays. I would perhaps be open to buying just a raw dual mode screen (not from Russia or Israel) and then use it to replace a cracked screen on a 2nd hand phone.
I guess it’s debatable relevance to solorpunk travel. Two phones in case 1 consumes a little more power overall but it keeps a phone out of the landfill and makes it useful.
That looks interesting. I might have to keep my eye out for these at the 2nd hand street markets. When you say supplement, do you mean the ROX feeds coordinates to the phone?
Apparently Sigma has a proprietary app for the phone. If you don’t use that app, are open standards supported? In the pre-smartphone days, it was common to get a dedicated device that merely ran a GPS receiver and the sent to coords to any bluetooth device (e.g. palm pilot) that paired to it. I think the standard is called NMEA. The ROX 4.0 manual makes no mention of NMEA so I’m not sure if that could be used to feed OSMand.
In any case, your finding seems to suggest using an external GPS has a substantial power savings on the phone that hosts the maps.
It is pretty limited device. You basically have to use the app but I found some 10 yo github repo that I will try (I have it only for few months).
I get the planned route to the device through the app (which is horrible) and have mobile on standby with same route. When the route inside is bad I crosscheck it with phone.
I figured out how to get .fit file dump of the recorded route out through USB (they don’t always sync to mobile). But don’t know how to get routes in without the app.
The device itself doesn’t have maps it only draws line and have some pre-programmed instructions (turns and intersections). I never tried using it connected to phone on ride (because the app is horrible), it has apparently some extra functionality that I don’t need.
Other option for me would be some Garmin but that is about 3-4 times more expensive.