Arc Low power mode vs Arc full interface

Hi, whats a difference between low power mode and full interface? I usually prefer not to enable low power mode on iPhone since it puts arc in low power mode. But even in this mode Arc shows “recording state: Recording” while battery is above 20%.
I wonder if i left low power mode enable on iPhone will it still record all locations as it normally does, or there will be less accuracy in tracking like missing out few locations?

Low power mode was my idea, and based on the idea that the GUI stuff in arc consumes tons of battery, while recording requires very little.

With the implementation, @matt made sure that recording accuracy is completely identical to normal recording. Only the processing of the raw data happens a little later, when low power mode is disabled again.


Yep, what @more said - the recording is the same both in Low Power Mode and normal mode. The purpose of the Low Power UI is to avoid the massive battery cost of the map view, as well as high energy cost from other bits of UI, such as confirm/edit views.

There is one slight difference in the recording during Low Power Mode. Arc’s recording engine will reduce its sampling frequency slightly. This typically has little to no noticeable difference in the amount of detail recorded, but is enough to shave a slight bit more energy cost off the total, allowing for marginally longer battery life.

Arc also automatically makes adjustments to the sampling rate based on battery level (reduced sampling frequencies when battery is under 20% and 10%) and on thermal state (reduced sampling frequencies when thermal state is “serious” and “critical”). When you manually switch your phone to Low Power Mode, Arc makes the same sampling frequency adjustment it would make when battery level is below 20%.

As @more says, UI stuff is orders of magnitude more energy expensive than recording. One minute of foreground screen time can consume as much battery as an hour or more of recording. So the Arc’s Low Power UI is designed to avoid that cost (from screen backlight, GPU, and CPU) as completely as possible.

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Recoding mode is now showing “sleeping” but battery level is at 95%

Yes that’s normal. Arc always goes into Sleep Mode when you are stationary. There’s no point in actively recording every movement when you’re stationary inside buildings, so regardless of whether you’re in Low Power Mode or not, Arc’s recording engine goes to sleep until you leave the building.

During Sleep Mode, Arc records new samples about once every 12 to 60 seconds, depending on how likely it thinks you are to leave soon (ie if you’re likely to leave soon, it’ll be recording samples more frequently, to accurately detect your leaving time, but if you’re not likely to leave soon then it’ll be recording samples less frequently).

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An extra detail on recording versus screen time battery consumption just came to mind: On devices with old, degraded batteries, a minute of screen time can be equal to several hours of recording.

As an example, one of my test devices is an iPhone 7 with a battery that’s degraded to 74% capacity, but it can still record full days with Arc on a single battery charge, from morning to night, as long as there’s little to no screen time. As soon as I unlock the phone and use it (ie lighting up the screen, and making some use of the GPU and CPU), the battery drops rapidly in minutes, and won’t last more than a couple of hours.

So in short: an ageing battery with reduced capacity can still record all day, but will drain quickly from use of screen backlight, GPU, and CPU.

Arc’s Low Power UI helps these ageing devices by reducing screen brightness (which reduces energy consumption on OLED models, eg iPhone X and newer, but not LCD models), and eliminating almost all of the UI’s GPU and CPU consumption.

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Low power mode saves really a lot of battery. Without low power mode, in 24hrs Arc consumed 18% battery (IP11, 97% health) and with low power mode it consuming daily just 5-7%.
Also low power mode seems to be more accurate over full interface mode. May be Arc is learning my activities but earlier locations and walking paths were not as accurate as low power mode now.

Honestly would be nice if there was a toggle on for low power mode