I think most of you smart-phone users wondered at a point why smart-phone batteries last too little and die very fast. Well, let’s take each case.
Reasons they drain very fast
1. Intentionally-made high power hardware. All smart-phone components drain a lot of power compared to their power sources. A smart-phone battery is double or triple the size and double or triple the capacity of a classic mobile phone battery and it last in average 3 times less. So we got a 6:1 ratio at best – that is exceptionally bad.
2. Uncontrolled Software. Of course, any software that constantly uses a lot of hardware resources will drain more power, so that help killing the battery a lot. And most of the high-drain software is there by default and cannot be disabled. The rest of the applications that are installed over time contribute too, but the base is already there. And no, app-killer apps don’t usually help because they actually drain power terminating other applications and then these respawn, get again terminated and so forth.
There are 2 things that can be done. Hardware modding of the phone will significantly help. More exactly, reducing CPU voltage. The procedure is called Undervolting and you can find tutorials on that depending on you exact phone model. CPU volt modding can double battery life. Try it.
For the second part (the software), if you really want to control your smart-phone, its best to replace that android OS with something open-source. Tzien, Plasma Mobile, Librem, PostmarketOS or LineageOS are all open-source alternatives. Test them, choose one and stick with it. If you actually control what runs on your phone, you control what drains your power.
Try the above and with good SW and HW control you can end up with 4 times the duration per charge for your battery.
Reasons they die very fast
1. Default Over-charge and over-drain. All smart-phones today overcharge the batteries. The standard full-charge chemical specification of Lithium-based batteries is 4.2V. This is the maximum value you should charge a Lithium-based battery in order not to damage it. You cannot change this, it’s chemistry. It happens the same no matter what. What you can do is optimize a manufacturing process so the result is less destructive. Over time, the smart-phone manufacturers started to cheat on the battery. They overcharge it in order to label it with extra capacity and they do not care that the battery dies very fast. Initially, they were only going towards 4.3V at full charge but now-days they even exceeded 4.4V at full charge. Just like over-clocking CPUs. The actual 4.2V value is now at around 80% at a smart-phone’s indicator. Another trick is to over-drain them; that also works. Initial drain Li-Ion value in the original specifications is 3.3V. Now many consider 3.0V the 0% capacity value, which is also cheating. They did not go too far with over-draining because at low voltage the battery will no longer sustain enough current to power-on the device and there’s nothing they can do there. But over-charging won’t stop you device to work, it can only set on fire the battery, so this is the limit currently pushed.
Here’s how they fake-increased the capacity, graphically represented:
The initial usable interval was 3.3V to 4.2V and now it’s being extended to 3.0V to 4.4+V Basically, more capacity, more battery damage. Any older Li-Ion battery or cell can be over-charged or over-drained but that’s not good for them.
2. The other contributing factor to the damage is temperature. Li-Ion at high temperature takes damage. You can safely use it in Siberia but not in the Sahara desert in day-time. There is nothing that can be done about this. You heat-up Li-Ion, it will take damage. You keep it cool, it will last long. See my previous cryo recovery article about the temperature issues.
What you can do to extend battery life is not to fully charge or fully discharge your phone battery. In fact, manufacturers count on the fact that you’ll plug it in before completely drained and un-plug it earlier because you’re in a hurry. So, if you want to have a long life for your battery, disconnect it at 81% charge and do not let it drain under 15%.
Charging conditions and charge current is also a factor, but I won’t go into this one now as it’s less important the the other factors.
– Update (20190215) –
I just installed out of curiosity on a J’series smart-phone a largely used battery monitoring application (AccuBattery). In the application, there are calculations stating that if I charge the battery to 80% it has over 5 times less wear than if charging to 100%. The over-charge ‘cheat’ is now confirmed by other independent sources.