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- Updates
- 2015-08-08: Request from comments below: Added description why I am using a timer switch at all.
- 2025-09-14: Method doesn't work for battery charge limits.
Many smartphone owners seems to live with a constant fear that their smartphone might die. A clear sign that you might be affected as well could be that you find yourself in a situation where you desperately need to charge your phone during the day.
My personal approach solved this issue for me once and for all: Close to my bed, I have a time switch installed. A dual-USB-charger is plugged in. The two cables are mounted along the bedsides and reside on/in the nightstand.
Whenever I go to bed, I plug in the phone after I shut it down. From 2a.m. to 5a.m. the USB cables get power from the time switch. Whatever battery status my phone had, I get a hundred percent battery capacity in the morning when I turn on the phone. Since my smartphone is able to deal with all kind of stuff for at least one day, I never ever have to think about the battery again. One thing less to worry about.
Of course, there are exceptions: For example whenever I travel, I do have to take a charger with me and I do have to think about charging again.
The purpose of the timer switch is that I want to define the charging hours. This way, I don't over-charge the battery for sure. This might not be an issue at all for modern smart phone batteries and their advanced charging logic. However, when I re-charge the battery every night, I don't want to take chances. Further more: I don't want to be annoyed by the LED that is on when the phone gets charged. By the time the timer switch turns on, I am already asleep. And it saves (a bit) power.
A remark on technical progress: Before smartphones were introduced, we had phones and PDAs with batteries that lasted for weeks.
Method Doesn't Work for Battery Charge Limits
Update: I have to add that this method does not work if you are trying to avoid long-time battery decline.
For that, you usually use the 80 percent charge limit for normal days. This feature was introduced for standard Android with version 15 in 2024.
Unfortunately, this only seems to be working when the smartphone is not switched off during the charge which I do during the night.
For that I tried a different method which is working somewhat reasonable but far from perfect. I charge our two smartphones using an older USB charger with poor charging performance. This reduces the charging speed automatically, not causing too much battery stress.
Furthermore, I'm using Shelly Plug S power adapters which I may control using Home Assistant. This adapter is only switched on starting from 2am. It charges our two smartphones in either case until 4am. After that, I keep the power flowing until the charging power is less than 5.5W. This is roughly the expected value when both smartphones start to reduce their charging consumption within their 60-80 percent charging status even when they are turned off.
Usually, this results in battery charge state from 50 to 80 percent in the morning.
So to be honest, if my phone has less than 60 percent in the morning, I now still started to worry about re-charging during the day. However, I get the benefit of having reduced battery stress and therefore some positive effects on long-term health status which might allow for longer device usage over the years.