[Xiaomi Redmi Note 5 / 5 Plus Guides, News, & Discu] Doomkopf:
Hey guys,

this thread is supposed to show you exactly, how you can change the charging voltage and charging current of the Xiaomi Redmi 5 Plus (vince). This could very well also work with other phones, as I first heard of them in a Magisk module, NOT related to this phone. This is my first thread on xda and I'm not a native speaker, so please excuse mistakes :)

So, there are two files associated with the kernel, that control voltage and current. For most kernels for vince, these files exist (DA, Zucc, Genom, and maybe also the others... doesn't work on Kirks Kernel) at the moment. Of course I don't know if these files still exist when a new android version is brought to this phone ^^

So let's start. The two files I mentioned are located here:

Current: /sys/devices/platform/soc/200f000.qcom,spmi/spmi-0/spmi0-02/200f000.qcom,spmi:qcom,pmi8950@2:qcom,qpnp-smbcharger/power_supply/battery/constant_charge_current_max

Voltage: /sys/devices/platform/soc/200f000.qcom,spmi/spmi-0/spmi0-02/200f000.qcom,spmi:qcom,pmi8950@2:qcom,qpnp-smbcharger/power_supply/battery/voltage_max

For Linux 3.18 Kernels:

Current: /sys/devices/soc/qpnp-smbcharger-18/power_supply/battery/constant_charge_current_max (stock value: 2000000 = 2000mA)

Voltage: /sys/devices/soc/qpnp-smbcharger-18/power_supply/battery/voltage_max (stock value: 4380 = 4,38V)

The values in constant_charge_current_max are measured in mA/1000. So that means, if you want to set 2000mA, you have to type 2000000 in this file.

The values in voltage_max are in mV, so if you want to set for example 4,2V as a maximum, you would have to type 4200 in this file.

MY RECOMMENDATIONS:

To set good values on these interfaces, we have to understand them correctly. Let's start with the voltage. The charging voltage (in order to charge) always has to be higher than the voltage the battery has. The battery of this specific phone ranges from 4,3V to 3,7V (4,3V on 100%, gradually going to 3,7V when reaching 0% (not sure about the 3,7V, correct me if you can :p )). I wouldn't change it. The voltage needs to be 4380 mA if you want you phone to charge until it's full. Even if you don't want that, I'd take another way to stop your phone from charging any further (there are good magisk modules that do exactly that, even with more features).

Now let's speak about the charging current, the holy grail of charging haha :laugh: Basically, if you want faster charging, go with values higher than 2000mA. I'd take 2500mA max, as the battery can get very hot. If you want your phone to stay cool while charging, which causes the battery to last way longer (https://www.sciencedirect.com/science/article/abs/pii/S0378775314004352), I'd recommend finding a charging current which keeps your temperature at about 25°C, which is the optimal temperature (see the reference, it's not a long text). For me, this is 1850mA, but if you live somewhere where it's very cold or hot, this can vary significantly. In the end, this is personal preference and should depend on how long you want to keep your phone, and how important charging speed is to you.

As for all kernel or /sys values, these will be reset on every reboot, so you'll have to find a way to set in on every boot. I tried creating a init.d file, but even though I set the permissions of the init.d file etc, it failed every time. So personally, I use Custom Controls in Kernel Adiutor, but I think EXKM has something similar. Of course I can only show the way with Kernel Adiutor and FKM in the following, as I don't have EXKM.

How to set these values with Kernel Adiutor:

For this, you have to enable the Custom Controls in Kernel Adiutor settings, if you disabled it previously.

Let's start with the current:

Go in the Custom Controls menu, click on the + and then "create". For this type of value, we need a seekbar. The title is irrelevant really, I'd choose "Charging Current". As a min, choose 0, and as max, choose the exact same value you want to use (if you're still unsure, just take 2000000/2500000, depending on if you want to increase it or not). I do this, because it is very hard to get the seekbar to an exact value (for example 1850000), because the numbers are so high. So i just set the max to what I want, and just max out the seekbar.

In "Progress", you have to put in exactly this:

For 3.18 kernels:

#!/system/bin/sh

head /sys/devices/soc/qpnp-smbcharger-18/power_supply/battery/constant_charge_current_max

Press test to confirm you typed it in correctly. Otherwise you also won't be able to set this control :)

in "Applying", put in exactly this:

#!/system/bin/sh

progress=$1

echo $progress > /sys/devices/soc/qpnp-smbcharger-18/power_supply/battery/constant_charge_current_max

Don't forget to delete the # before the second line (progress=$1), otherwise this will set nothing.

For 4.9 kernels:

#!/system/bin/sh

head /sys/devices/platform/soc/200f000.qcom,spmi/spmi-0/spmi0-02/200f000.qcom,spmi:qcom,pmi8950@2:qcom,qpnp-smbcharger/power_supply/battery/constant_charge_current_max

Press test to confirm you typed it in correctly. Otherwise you also won't be able to set this control :)

in "Applying", put in exactly this:

#!/system/bin/sh

progress=$1

echo $progress > /sys/devices/platform/soc/200f000.qcom,spmi/spmi-0/spmi0-02/200f000.qcom,spmi:qcom,pmi8950@2:qcom,qpnp-smbcharger/power_supply/battery/constant_charge_current_max

Don't forget to delete the # before the second line (progress=$1), otherwise this will set nothing.

That's it, you can use this control now ^^ But if you want this to set on every boot, after setting it up, you have to click on the 3 dots of this control and check "On boot".

Basically, for the voltage, I'd take 0 as minimum, and 4400 as maximum, and change the file location to the voltage (on progress and applying), and the rest is the same!

So, that's it! It's possible that someone will write a magisk module for that some day, but until then, I think this is a very easy solution. Have fun with it!

How to set these values with Franco Kernel Manager:

These screenshots are provided by [MENTION=10393715]Niamotullah[/MENTION]

[IMG="Step 1"]https://i.imgur.com/CRL7VAW.jpg[/IMG]

[IMG="Step 2"]https://i.imgur.com/fRlQ5yH.jpg[/IMG]

[IMG="Step 3"]https://i.imgur.com/sNpiAUi.jpg[/IMG]

[IMG="Step 4"]https://i.imgur.com/7lOjpVO.jpg[/IMG]