Database Users

DIY External Battery Questions

Guys, I've looked around some, but can't find the information I need for this project. I've come into posession of a friend's Nexus 7 8GB that's cracked, as I have two projects in mind for it. The first is making my own external battery pack with the battery from the tablet.
I know the battery is rated for 3.7V at 4325mAh. A standard USB input is powered with 4.5-5.5V. I'm somewhat electrically knowledgeable, but I'm stumped on how to make sure I don't fry my phone or my Nexus 7 by plugging this battery into the USB port. My other dilemma is charging the battery back up, I'm assuming that this will take a small circuit to do.
Any ideas?
Thanks,
Austin

atminside said:
Guys, I've looked around some, but can't find the information I need for this project. I've come into posession of a friend's Nexus 7 8GB that's cracked, as I have two projects in mind for it. The first is making my own external battery pack with the battery from the tablet.
I know the battery is rated for 3.7V at 4325mAh. A standard USB input is powered with 4.5-5.5V. I'm somewhat electrically knowledgeable, but I'm stumped on how to make sure I don't fry my phone or my Nexus 7 by plugging this battery into the USB port. My other dilemma is charging the battery back up, I'm assuming that this will take a small circuit to do.
Any ideas?
Thanks,
Austin
Click to expand...
Click to collapse
Hey Austin,
tell us exactly how you would like this battery to be used-
1. do you want to recharge battery over the USB port?
2. for what exactly you want to use the battery? For some other device? or for Nexus 7? Be more specific please.
I would generally advise if you want to do cool thing like
"external battery that can be hooked to device on-the-go as a mobile range extender"
you want to do this?
in this line of thinking we take note of;
-Voltage of battery nominal
-Voltage of the charging sources (110V,220V,USB +5V /4.5-5.5V/ )
+now when you are sure of this here you go
-at the bare minimum;
- resistors to lower the voltage in/reduce charging current (yes,minimalistic circuit),with a method to check/determine when battery is nearly full 99% cap as per li-ion battery requirement.Take note lithium ion batteries are absolutely forbidden to be overloaded or else kaboom!, self destruct, fire etc./take a look at youtube "li-ion self destruct"
-dig the li-ion charge reqs and methods from the available knowledge sources (e.g. the internet,electronic forums)
Are you up to this project?Wanna companion for this?Just let me know..

You need 3 things to use a raw battery as a USB source:
- a boost converter, to convert the battery's approximately 3.7V to a stable 5V
- a battery charger
- a protection circuit
The protection circuit is very important. If you over-discharge or over-charge a Li-ion battery, you can run into (explosive) trouble.
The battery may have a circuit on board. Can you see any circuitry in the cell? How many wires come out of it?
For example, eBay has plenty of random parts that should do the job:
Protection unit
Charger
Boost converter

You'll want to be really careful if the battery doesn't have on-board protection circuity. Lithium based batteries tend to explode or catch fire if they're improperly charged. Heck, you even hear about it happening to batteries in phones while they're in peoples pockets. Though I would assume some are from dodgy third party batteries.
You might be able to use something like the LiPo Rider Pro which is a premade board for charging Lithium Polymer batteries. It has two USB ports, one for charging and one for supplying power.
If you've never designed a power supply PCB before then I recommend using a ready made device like that, otherwise you could end up getting burned, literally.

A few years ago I just used one of those big 6V batteries and put a USB connector on it. Worked without any problems!

jhlaird said:
You need 3 things to use a raw battery as a USB source:
- a boost converter, to convert the battery's approximately 3.7V to a stable 5V
- a battery charger
- a protection circuit
The protection circuit is very important. If you over-discharge or over-charge a Li-ion battery, you can run into (explosive) trouble.
The battery may have a circuit on board. Can you see any circuitry in the cell? How many wires come out of it?
For example, eBay has plenty of random parts that should do the job:
Protection unit
Charger
Boost converter
Click to expand...
Click to collapse
This is of interest to me. I have a Zerolemon 7000mah battery and I'd like to use it as a recharging power pack for my i747 Gs3. With the newer high capacity batteries, this seems like a natural to me--if I'm out somewhere and don't want to put the Zerolemon in my Gs3, just hook it up to recharge. Is the lack of this kind of accessory due to varying battery types? I'd buy something like this if I could find one.

How to make it:
atminside said:
Guys, I've looked around some, but can't find the information I need for this project. I've come into posession of a friend's Nexus 7 8GB that's cracked, as I have two projects in mind for it. The first is making my own external battery pack with the battery from the tablet.
I know the battery is rated for 3.7V at 4325mAh. A standard USB input is powered with 4.5-5.5V. I'm somewhat electrically knowledgeable, but I'm stumped on how to make sure I don't fry my phone or my Nexus 7 by plugging this battery into the USB port. My other dilemma is charging the battery back up, I'm assuming that this will take a small circuit to do.
Any ideas?
Thanks,
Austin
Click to expand...
Click to collapse
Steps:
1. Learn or know battery and charger technology - especially concerning heat and fire safety. You do not want your house or car burn down "just because you hacked together a little interesting project". Take full consideration of all the sides of it. Experience..
2. Do it.
3. Share it here.
4. Evolve the design together with electronic-savy guys here.
Thats that.
Aside of the notes above - it is an interesting stuff if you have time for it.

Replace or mod battery connector?

hi
i got a phone that doesnt charge and barely turn on, i think its the battery connector that is defected on the phone. The pins doesnt looks good. Im wondering if its hard to replace the battery connector myself ? or is there a way to recable a way to pass the battery connectors pins ?
talking about this: http://rounded.com/samsung-3711-008737-battery-connector-3711-008737.html

oopeteroo said:
hi
i got a phone that doesnt charge and barely turn on, i think its the battery connector that is defected on the phone. The pins doesnt looks good. Im wondering if its hard to replace the battery connector myself ? or is there a way to recable a way to pass the battery connectors pins ?
talking about this: http://rounded.com/samsung-3711-008737-battery-connector-3711-008737.html
Click to expand...
Click to collapse
it seems that connector is part of motherboard:
https://www.youtube.com/watch?v=hSz2IsaHuLI
if that is true you need a motherboard or a guy with good skills on welding.
that phone has no warranty, right?

Rajada said:
it seems that connector is part of motherboard:
https://www.youtube.com/watch?v=hSz2IsaHuLI
if that is true you need a motherboard or a guy with good skills on welding.
that phone has no warranty, right?
Click to expand...
Click to collapse
yes the phone still have warranty but I talked with them and mostly it doesn't cover the battery connector.... and they couldn't give me a price to replace it, but I bet it will be expensive

That actually looks pretty simple to replace if you are handy with a solder iron?

kPATm said:
That actually looks pretty simple to replace if you are handy with a solder iron?
Click to expand...
Click to collapse
I I'm pretty rusty with the iron
anyone know if I can cable the battery to the qi contacts on the phone or anything to bypass the battery connector ?

oopeteroo said:
I I'm pretty rusty with the iron
anyone know if I can cable the battery to the qi contacts on the phone or anything to bypass the battery connector ?
Click to expand...
Click to collapse
Well yes, that's a workaround. You can still buy a Qi-enabled back door or just buy the paper that goes conected to the pins and place it between the battery and the back cover itself (I don't remember the name, but there are a lot in Amazon or Aliexpress).
By the way if you want this phone to be your daily driver, I suggest you to get it fixed. Wireless charging is painfully slow, phone cases doesn't fit with aftermarket Qi enablers or even the genuine back door and they probably don't work with the charging base either. Also with WiFi you wouldn't be able to transfer files or even flash roms between your phone and your pc as fast as with an USB cable. Now if it will be your secondary phone then sure, grab a Qi cover or get an external battery charger and problem solved. Good luck!

galaxynote2 said:
Well yes, that's a workaround. You can still buy a Qi-enabled back door or just buy the paper that goes conected to the pins and place it between the battery and the back cover itself (I don't remember the name, but there are a lot in Amazon or Aliexpress).
By the way if you want this phone to be your daily driver, I suggest you to get it fixed. Wireless charging is painfully slow, phone cases doesn't fit with aftermarket Qi enablers or even the genuine back door and they probably don't work with the charging base either. Also with WiFi you wouldn't be able to transfer files or even flash roms between your phone and your pc as fast as with an USB cable. Now if it will be your secondary phone then sure, grab a Qi cover or get an external battery charger and problem solved. Good luck!
Click to expand...
Click to collapse
but the qi wireless only do the charing ? or does it power the phone with the battery also ? because I think I need a way to bypass the battery connector to get more stable power on

also there is 4 pin-outs anyone know what does what ?

Battery, Charger, or Cable Issue with Fast Charging

Hi guys, greetings!
I'm a new member here
Apparently, I had issue with fast charging problem. Basically what I did was changing cable and charger over and over again. I had to change my cable to which can hold up to 2.1A and a charger that has same output with stock charger which is 5V at 2A and 9V at 1.67A. I even bought enough cables just to see whether it is working or not, yet it doesn't fix my problem. I haven't changed my battery since this issue, I assume that this issue don't came in the battery rather it is from cable or charger. So I changed my flexy charge, but still can't do such a thing.
I had to reset my phone and factory settings, and yet it doesn't fix my problem
For some reason I'm frustrated with normal charge because I had to wait my phone fully charge like around 6 hours. And it drain also around 6 hours on use continuosly.
But it's crazy that this phone can hold it reliable for 6 years without any issue. It still in better shape. My only issue that came up was camera focus, can't read my sim card, and fast charging issue. And a missing S Pen lol. The camera focus and sim card aren't a big issue, since I can use alternative phone. And I can wait longer for my camera to focus to one object.
My questions are :
1) Does the battery affect fast charging too? I have my stock battery here which is 3220 mAh. If it's true, then maybe I'm going to change my battery with a newer one.
2) Is it possible that the processor in it some tiny part (which it controls the fast charging) is broken and that's why fast charging is stopped working?
3) I need to upgrade my phone to a same note series, but it's hard to pick. I kinda like galaxy note 9 than a newer one. But I want you guys to give me opinion. I need a longer battery life and it said note 9 is a beast battery. And a compatible software updates in future.
4) Does the battery that comes up with custom battery capacity is safe? Like does it fast charging? (like a ZeroLemon 11000 mAh and some chinese product that doubles the capacity stock battery)
5) Does the OS affects too? (This is the reason I did factory settings so I can see if it's work or not)
Thank you guys!
I'm using my N910C

fahadnajed said:
Hi guys, greetings!
I'm a new member here
Apparently, I had issue with fast charging problem. Basically what I did was changing cable and charger over and over again. I had to change my cable to which can hold up to 2.1A and a charger that has same output with stock charger which is 5V at 2A and 9V at 1.67A. I even bought enough cables just to see whether it is working or not, yet it doesn't fix my problem. I haven't changed my battery since this issue, I assume that this issue don't came in the battery rather it is from cable or charger. So I changed my flexy charge, but still can't do such a thing.
I had to reset my phone and factory settings, and yet it doesn't fix my problem
For some reason I'm frustrated with normal charge because I had to wait my phone fully charge like around 6 hours. And it drain also around 6 hours on use continuosly.
But it's crazy that this phone can hold it reliable for 6 years without any issue. It still in better shape. My only issue that came up was camera focus, can't read my sim card, and fast charging issue. And a missing S Pen lol. The camera focus and sim card aren't a big issue, since I can use alternative phone. And I can wait longer for my camera to focus to one object.
My questions are :
1) Does the battery affect fast charging too? I have my stock battery here which is 3220 mAh. If it's true, then maybe I'm going to change my battery with a newer one.
2) Is it possible that the processor in it some tiny part (which it controls the fast charging) is broken and that's why fast charging is stopped working?
3) I need to upgrade my phone to a same note series, but it's hard to pick. I kinda like galaxy note 9 than a newer one. But I want you guys to give me opinion. I need a longer battery life and it said note 9 is a beast battery. And a compatible software updates in future.
4) Does the battery that comes up with custom battery capacity is safe? Like does it fast charging? (like a ZeroLemon 11000 mAh and some chinese product that doubles the capacity stock battery)
5) Does the OS affects too? (This is the reason I did factory settings so I can see if it's work or not)
Thank you guys!
I'm using my N910C
Click to expand...
Click to collapse
Check your microUSB port and make sure the little flap in the port isn't bent and if it's dirty carefully clean the port. If you still have the original battery that came with your phone it will definitely need replaced with a new one. Lithium-ion battery degrade over time and have limited life span.
https://www.google.com/amp/s/www.bu...ies-are-only-meant-to-last-a-year-2015-10?amp
https://www.google.com/amp/s/www.androidcentral.com/how-tell-when-phones-battery-has-gone-bad?amp

Mr. JAVI said:
Check your microUSB port and make sure the little flap in the port isn't bent and if it's dirty carefully clean the port. If you still have the original battery that came with your phone it will definitely need replaced with a new one. Lithium-ion battery degrade over time and have limited life span.
Click to expand...
Click to collapse
Yes! I did that before I changed my flexy charger. It didn't fix my problem. It seems like there's some tiny part in processor is broken for some reason (like I told in this thread) or maybe some part an IC in the motherboard who controls it also damaged. I really don't understand how fast charging works.
I came up with a solution that I bought two new stock batteries and a desktop charger. So if my phone's battery is run out, I could change with my alternative battery. But I'm still frustrated for how it can't fast charging again.

1- Try cleaning the charging port with izoprophilic alcohol and some small brush (let dray the port 1-2 hours after, DON'T START the phone)
2- Make sure you have a quality charging cable (the 5$ from gas station or chinese cheap crap there are no good)
3-Same thing like at point 2 but with charger
I have like 3-4 charging flex with ports for note 4 and all are faulty so maybe this if you buy from china or ebay and its not from broken phones original.
If you have all good quality charger and cable and good charging port maybe IC power managament on motherboard is faulty, not CPU.
You can fix it but depends where you live will be more expensive than buying a second hand motherboard from aliexpress, its like 30$ I buy recently for a N910C
Me I don't use fast charging becouse its get too hot and is a secondary device
I want to buy and me a bigger battery I found on batteryUpgrade a 6900mAh but I don't know the quality and its almost 50$

Marian94 said:
1- Try cleaning the charging port with izoprophilic alcohol and some small brush (let dray the port 1-2 hours after, DON'T START the phone)
2- Make sure you have a quality charging cable (the 5$ from gas station or chinese cheap crap there are no good)
3-Same thing like at point 2 but with charger
I have like 3-4 charging flex with ports for note 4 and all are faulty so maybe this if you buy from china or ebay and its not from broken phones original.
If you have all good quality charger and cable and good charging port maybe IC power managament on motherboard is faulty, not CPU.
You can fix it but depends where you live will be more expensive than buying a second hand motherboard from aliexpress, its like 30$ I buy recently for a N910C
Me I don't use fast charging becouse its get too hot and is a secondary device
I want to buy and me a bigger battery I found on batteryUpgrade a 6900mAh but I don't know the quality and its almost 50$
Click to expand...
Click to collapse
Yes, I also did that way before I change my flexy charger. I brushed it with izoprophilic alcohol on charging port.
I'm pretty sure all I have is a high quality charger and cable. I still have my stock charger. I think there's no issue with charger, I couldn't really tell, since I tried all possible different charger. But with the cable, yes, I tested it one by one, because the issue might come from cable.
I think after all I did what's possible, there's something wrong with my IC charging or processor. I couldn't understand it but, does it guarantee if I changed like I pull the broken IC and put it back a new one, will do the fast charging?
But really though, how does fast charging works? Is it include in processor by some tiny part transistor? or is it an independent IC in the motherboard?

100% is another chip on motherboard that do the charging
I have a similar problem with a samsung tab s t800 that charging very slow becouse of faulty IC power manageament
I'm opened my note 4 for many times until now and repairing it
I've been watching many board repairs I have some skills but no tools to repairs bords for now
Its not the CPU
I watch a similar board fix on note 9 and was a diferent chip on board that manage the charging
Go to a service if you want to repair, don't try to do something at home becouse you have hight chances to destroy much more the phone
Repairing you phone at a repair shop will be more than 30$ so better buy a "new" motherboard from aliexpress

No battery.. Any way to turn on?

Recently digged out my old Qtek 9000 from the closet, and want to get it turned on again, but i have no battery.. It had swollen up years ago, so i threw it out.
Is there any way i can get the device to turn on again? Plugging in the mini usb charger, and i get a steady red led on the device but not able to turn it on. I tried attaching a powersupply of 3.7v to the + and - min but still nothing..
Any tricks?

Replace battery. It can damage the device severely or worse.
Any swelling is a failure.
Do Not attempt to charge a failed Li!!!
Without the battery to supply enough current, it can not boot. The charger can't sink enough current for a boot up...

blackhawk said:
Replace battery. It can damage the device severely or worse.
Any swelling is a failure.
Do Not attempt to charge a failed Li!!!
Without the battery to supply enough current, it can not boot. The charger can't sink enough current for a boot up...
Click to expand...
Click to collapse
Where to find a battery in the EU though?

Don't know. Sorry. Li's have a limited self life too of about 3-4 years max.

blackhawk said:
Don't know. Sorry. Li's have a limited self life too of about 3-4 years max.
Click to expand...
Click to collapse
Oh.. Guess its a goner by now then. What a shame. Thanks for your input!

Da9L said:
Oh.. Guess its a goner by now then. What a shame. Thanks for your input!
Click to expand...
Click to collapse
You can find or adapt a battery if you put some time into it... depends if it's worth it to you.
I have a 12yo flip top ruggedized phone that still boots

So to get the device to turn on with a another battery of the same voltage.. Should i only need to connect the two pins on each end of the pins on the device ?

Da9L said:
So to get the device to turn on with a another battery of the same voltage.. Should i only need to connect the two pins on each end of the pins on the device ?
Click to expand...
Click to collapse
If there's only 2 pins, yes. The polarity must be correct!
Soldering to the mobo van be tricky if you're not proficient at doing it. Not the place to learn! The mobo landings can easily be destroyed by excess or prolonged heat. Prolonged is measured in seconds like 1-3 @ 725F with well tinned tip using 60/40 or better 63/37 lead based rosin core solder only. A tin or bottle of rosin flux can be useful.
You may only get one shot at it...solder pad landing repairs are even more difficult.
It wire is used, very thin gauge stranded only and always pretinned.

Nook OG Running on Charger

I have two original nook first editions, both had puffy batteries, and would not charge or turn on, I took out the batteries, but was wondering if I can run them off of their chargers. Would be willing to root or run new software, I just want to see them run again... thanks!

farmerstele3 said:
I took out the batteries, but was wondering if I can run them off of their chargers.
Click to expand...
Click to collapse
Maybe. There's a couple of problems here.
The first is simply that the USB charging circuit usually can't deliver the peak current required by the device.
Next is the fact that the battery check is probably in different places in the code.
It's easier to pretend that you have a battery.
That means that you need a 4V to 4.3V supply connected in where the battery was.
Depending on how many wires go to the battery pack there may be temperature sensors or ID resistors.
You need to keep the old ones or implement new ones.
I've got half a dozen devices that have been so modified.
How many wires/colors does the battery connector have? Photo would be appreciated.
You need to either reuse the little BMS circuit board or measure it and implement it.
Here's a photo of my brand new Walmart Onn8 tablet that is running off a 4V supply

Renate said:
Maybe. There's a couple of problems here.
The first is simply that the USB charging circuit usually can't deliver the peak current required by the device.
Next is the fact that the battery check is probably in different places in the code.
It's easier to pretend that you have a battery.
That means that you need a 4V to 4.3V supply connected in where the battery was.
Depending on how many wires go to the battery pack there may be temperature sensors or ID resistors.
You need to keep the old ones or implement new ones.
I've got half a dozen devices that have been so modified.
How many wires/colors does the battery connector have? Photo would be appreciated.
You need to either reuse the little BMS circuit board or measure it and implement it.
Here's a photo of my brand new Walmart Onn8 tablet that is running off a 4V supply
Click to expand...
Click to collapse
I'll have to rip it apart again, so it will be a while.