This is similar to my question but I don't think the OP explained it well. I want to essentially have a charger where I can define the charging limit. The point being that it is bad for your phone battery to be charged to 100% and even worse to be kept there (like overnight charging). In general, it is best to charge them to ~80-85%. There are apps that can do this but they require root access.
That said, I thought it would be a fun project to attempt to make a USB charger that could be programmed with a custom cut-off percentage. It would be even better if you could define high/low and have it stop/start as needed.
I am familiar with basic programming but am unfamiliar with the hardware aspect like Arduino and that is where I would like some guidance.
I see two main aspects here:
Stopping/starting the actual power flow to the phone
This seems like it shouldn't be that difficult as the actual LiPo charger is in the phone and the USB only supplies the juice. Some kind of relay?
Monitoring battery percentage as reported by the phone
I haven't looked into this much but I presume this should be doable since devices like my car are able to get this data via USB connection.
bluesk1d:
The point being that it is bad for your phone battery to be charged to 100% and even worse to be kept there (like overnight charging). In general, it is best to charge them to ~80-85%.
I miss numbers in those articles on how much the damage really is. How much does it affect capacity or overall lifetime, really?
The problem doesn't seem to be too great. I'd rather have my phone at 100% when I leave home than at 80% or so. Unless I carry a separate battery I normally have no chance of recharging on the go, even with more and more buses offering USB outlets at the seats.
You realise that the smarts for the charger are inside the phone?
What makes you think you know more about battery chemistry and safety than the phone manufacturer?
If you can ask the phone at what charge level it is (install an app, connect over Bluetooth or WiFi), you can have an Arduino switch on or off the charger externally.
I can't find where the OP asked if you agreed that this is a good idea or not. seems to me research into android ios, and programing for android ios is required, the arduino side will be easy once you can give the arduino values for current phone charge%. i don't know anythin about android ios, but good luck to you.
Not going to stop OP from shooting themselves in the foot (well, as long as I can be quite confident it's not in a way that might actually get them killed).
That doesn't mean I'm going to take claims on how those batteries work and should be treated at face value. As said, the biggest hole is that the linked articles don't give any information on how much it really affects battery life. No claims, no test results, nothing. It's not that hard to set up some experiments.
Take two batteries. Measure the total charge they hold (by doing a full discharge).
One you charge full, then drain it empty over the course of 6-8 hours. Charge it full, repeat, until 12 hours passed. Then leave it on a charger for 12 hours.
Another one you charge/discharge between 40 and 80% for the 12-hour cycle, then charge to 80% and let it sit for another 12 hours.
Make sure the total amount of charge/discharge the batteries take is the same.
Run the experiment for 3-6 months, then measure the total charge both batteries hold now. See how much of a difference there is between the two. That will give you a clear indication of how much extra wear and tear the full charging/discharging gives.
jremington:
The OP actually believes what he/she finds in selected sites on the web.
You can rely, for example, on articles found on "https://www.popsci.com/" because they are contributed only by the top experts in the field
sigh I had hopes this forum wouldn't be full of anonymous douche-baggery and smug, zero value-add replies.
If you are totally hung up on the why and don't care for the sources I provided in 2 seconds of Googling, go do you own reading since there's no shortage of research on the matter. I'm not here to convince you what you should do with your own phones.
I want to maximize the life/performance of my own batteries and and it sounded like a fun side project. I am asking here because I am new to electronics and Arduino-like devices in general.
If you want to tell me how dumb I am, just PM me so the thread isn't derailed in the off chance someone actually wants to help.
Don't forget the phone/battery manufacturers have to keep their products safe.
They don't know if the device will be kept in an outside pocket in a jacket in an Alaska/Siberian winter, or left on a dashboard in Dubai/Oaxaca/Borneo.
wvmarie you are absolutely correct, and that sounds like a cool experiment, however i don't think the OP is trying to discuss proper battery care. He or she is trying to make a battery charger that charges the battery the way he wants it to be charged, which he discribed fairly well up top.
wvmarle:
Not going to stop OP from shooting themselves in the foot (well, as long as I can be quite confident it's not in a way that might actually get them killed).
That doesn't mean I'm going to take claims on how those batteries work and should be treated at face value. As said, the biggest hole is that the linked articles don't give any information on how much it really affects battery life. No claims, no test results, nothing. It's not that hard to set up some experiments.
Take two batteries. Measure the total charge they hold (by doing a full discharge).
One you charge full, then drain it empty over the course of 6-8 hours. Charge it full, repeat, until 12 hours passed. Then leave it on a charger for 12 hours.
Another one you charge/discharge between 40 and 80% for the 12-hour cycle, then charge to 80% and let it sit for another 12 hours.
Make sure the total amount of charge/discharge the batteries take is the same.
Run the experiment for 3-6 months, then measure the total charge both batteries hold now. See how much of a difference there is between the two. That will give you a clear indication of how much extra wear and tear the full charging/discharging gives.
The android app I linked will do this for you.
roosterqmoney:
wvmarie you are absolutely correct, and that sounds like a cool experiment, however i don't think the OP is trying to discuss proper battery care. He or she is trying to make a battery charger that charges the battery the way he wants it to be charged, which he discribed fairly well up top.
I do feel like it's very possible that the 100% you see on the phone screen is actually 80% of the battery's max charge, i.e. phone manufacturers already know everything mentioned in the article and have taken care of it in the phone's software. although they make money if you have to replace your battery soo could go either way.
100% generally refers to total capacity at that time. When the phone is brand new, it's 100% of the initial allowed capacity. As the battery ages, the phone keeps track of capacity loss and adjusts what 100% is. That's why even your old phone reaches 100% but drains more quickly.
It sounds like you understand that the objective here is to keep that high water mark as high as possible for longer. It's not saving the world or anything, just something I thought would be fun.
bluesk1d:
100% generally refers to total capacity at that time. When the phone is brand new, it's 100% of the initial allowed capacity. As the battery ages, the phone keeps track of capacity loss and adjusts what 100% is. That's why even your old phone reaches 100% but drains more quickly.
So if you're using the phone's reported capacity to drive your "smart" charger . . . I'm sure you can see where this is leading . .
TolpuddleSartre:
So if you're using the phone's reported capacity to drive your "smart" charger . . . I'm sure you can see where this is leading . .
I see what you are getting at but it's actually desired to hit 80% of what the current capacity is. That diminishes over time but at a much shallower curve since you aren't degrading the battery as much from the get-go.
Again, I am not here to sell anyone on the idea. I am just interested in the how
