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When you use the Trailmap mobile app for navigation or for recording longer rides (over 2 hours), it's worth getting to know the ways you can cut power consumption, so that your phone's battery lasts the whole ride.

The most important one is the navigation view's own power saving, which you have to switch on — it isn't on by default. When you're navigating a route it dims the screen automatically whenever you don't need the map, and wakes it up in good time before turns. When you're only recording, dimming is manual instead: the screen dims and brightens when you touch it. This power saving replaces the earlier, separate power saving that used to be in the app's settings. On top of that there are a number of manual adjustments you can make to cut consumption further.

Navigation's own power saving

You choose the power saving mode from the navigation view's Actions menu, and there are three options:

• Off — no power saving. The screen and map run at full power.
• Basic — when navigating a route, the screen dims on the quiet stretches and brightens automatically at turns or when you touch it. Location and map refresh rates are also lowered slightly. A good everyday choice for most rides.
• Maximum — like Basic, but on the quiet stretches the screen goes almost black and the map is hidden entirely. The map and brightness come back just before the next turn. The most effective way to save power when you're mainly relying on voice guidance.

The automatic dimming described above applies to route navigation. When you're only recording (with no route), dimming is manual: you dim and brighten the screen yourself by touching it. Be careful not to move the map by accident — just tap the screen briefly. You can read more about how the navigation view works in the navigation guide.

Below we go through the main factors that affect power consumption, and for each one the ways to reduce it — both automatic and your own manual adjustments.

The screen

The screen uses clearly the most power, so reducing its consumption makes the biggest difference. The most important thing is to keep screen brightness as low as possible. Navigation's power saving largely handles this automatically by dimming the screen on the quiet stretches, but you can adjust it yourself too: the Dimming setting controls how dark the screen goes (two levels), and on iPhone there's also a Brightness slider for setting the "bright" state to suit the light around you. In bright sunshine it's worth turning the brightness up; in dim light, less will do.

The second important thing is using a simple or black base map. The base map is a simpler version of the default map, which makes it easier to read even at lower screen brightness. The black version reduces the screen's power consumption further, because a modern OLED screen uses no power to display black pixels. You always choose the dark map yourself from the navigation view's Map settings ("Dark map") — it doesn't come on automatically, not even in Maximum mode. So it's worth switching the dark map on separately, especially together with Maximum mode.

For mounting your phone on the bars, it's worth using something other than a "pouch" with a plastic film over the screen. The plastic film causes reflections and reduces contrast, which forces you to use a higher screen brightness.

Processing

Showing the map on the phone's screen always takes a certain amount of processing power, which eats battery. Two ways to reduce this were already mentioned above: using the dark and simple map (lighter to draw) and hiding the map when you don't need it. When navigating a route, Maximum mode hides the map automatically on the quiet stretches. Power saving also lowers the map's refresh rate when the screen is dimmed.

One more option, which for many is a slightly bigger question of getting used to it: turning map rotation off. When the map doesn't rotate to match your direction of travel, the processing needed to move it gets simpler. You can change how the map rotates from the location button in the navigation view.

Location

You can adjust the power consumption of location in two ways: by keeping "GPS high accuracy" switched off (the default; it's in the navigation view's GPS settings) and by setting power saving to Basic or Maximum, which lower the location refresh rate and therefore power consumption.

Fetching map tiles over the network

The app uses a cache for fetching map tiles (the pieces the map on your screen is made of) from the cloud server, so they don't have to be fetched very often. On a very poor mobile network this can still add somewhat to power consumption. In the Android version you can put the map into offline mode, so no new map tiles are fetched at all; on iPhone you can use airplane mode. The effect of these on power consumption is usually very small.

Power consumption in practice, and some solutions

Using power saving mode, power consumption on an iPhone typically stays around 10–20 % per hour. On Android phones consumption is higher and the variation between phones is considerable, generally landing on either side of 20 %. In Maximum mode consumption is clearly lower than with the screen at full. These estimates assume a battery in relatively good condition and a temperature of +15 degrees. A battery in poorer condition, and cold temperatures in particular, affect power consumption significantly.

If you like, you can also attach a power bank to your phone, which at the least slows down the drain on the phone's own battery, if it doesn't stop it altogether. Outside air temperature affects this too, significantly. Mounting a power bank on the top tube or down tube does of course bring extra faff.

If you find yourself riding a lot of rides over 3 hours, a good option is to get a separate bike computer that records your rides and offers navigation for the easy sections of the route. Garmin devices are popular, and it's easy to send a route to them straight from Trailmap (as it is from many other apps too). Even though a device like this costs a bit, the benefits are reliability and vastly better battery life — and there's less risk of noticing your phone battery is only half charged just as you're about to head out.

I use the combination shown in the photo on both my mountain bike and my gravel bike. My phone is usually in the back pocket of my jersey, and only on the bars when I'm using it to navigate the trickier sections of a route. Quadlock has proven to be a reliable way to mount a phone on the bars, and attaching and detaching it is easy to do on the move too.

My bike setup