Hey all! I signed up here when I started my bachelors in EET and I finished it a few years ago. Sadly none of the information stuck with me....

My goal is to create a variable current usb charger to charge my phone, between 0 mA and 1,000 mA. The feedback would be based off of the phone's battery capacity. The goal is to keep it between 60% - 78% for longevity.

Not sure where to start... i'm guessing with an arduino, but then what? I can handle the software part a lot more easily than the electronics, so getting the battery capacity sent to the arduino shouldn't be an issue, but the hardware part is what I find most challenging.

Thank you for the help, if anyone can point me in the right direction. I'd prefer to buy COTS stuff rather than breadboard it.

-Greg

 

Your phone already has charge-control circuitry built in and expects to receive a fixed 5V supply. Not sure it would happily accept something trying to over-ride its own circuit.

 

Alec,

There is no way to stop the phone from charging once 80% SoC is reached. This will extend the life of the battery and is not exactly "" overriding "" the charging circuity, just cutting it off and trying to find a current where i'm only running the phone and not charging the battery.

 

How will your intended circuit measure the discharge current and state of charge of the battery? Without that info you won't know when to terminate the charge.

 

Alec, I will be monitoring the SoC through an app and sending it to the Arduino, then I'll use some sort of PID to keep the charge stable.

 

This is an old thread but I've been googling around and it's the only mention of this I can find. I don't know why this subject does not have more interest. Anyone with a cell phone that is always at 100% (like an Uber driver) is craving something like. I don't drive that much but my phone can easily be left at 100% all the time if I don't watch out and I've paid for it with shorter battery life. I've found using several USB extender cables in series can keep charging to almost the "break even" point where I can just leave it plugged it while driving for example, but I really want a better solution like the one mentioned here. Is there any progress on this?

 

This is an old thread but I've been googling around and it's the only mention of this I can find. I don't know why this subject does not have more interest. Anyone with a cell phone that is always at 100% (like an Uber driver) is craving something like. I don't drive that much but my phone can easily be left at 100% all the time if I don't watch out and I've paid for it with shorter battery life. I've found using several USB extender cables in series can keep charging to almost the "break even" point where I can just leave it plugged it while driving for example, but I really want a better solution like the one mentioned here. Is there any progress on this?

Maybe something like this controlled by a filtered pwm output from your mico?
https://www.analog.com/en/design-ce...ge-controlled-current-source.html#cc-overview