Anyone been able to turn on this phone and run it without a battery with permanent power?
Short answer: not possible.
Longer answer: You would need a pretty hefty engineering brain to figure this out, as the circuitry of the daughter board detects and adjusts the mainboards voltages and such, based on the battery output. When battery output is 0, meaning dead/removed battery, the daughter board doesn't supply voltages to the mainboard.
Now, you could replace the battery with a supercapacitor, but you'd need to have a pretty big one to output the current of a fully charged battery of the 6P - something around the 10kf mark, which IIRC from my university days, is roughly the size of 2 D-cell batteries or so. You'd then need to wire this all in, and even if you made it neat and 3D printed a new back, you went from a slim phone to a small brick. You'd also still need to provide current to charge the super capacitor, which doesn't use normal voltages like the charger and daughterboard can output, so you'd need to add in a voltage regulator board, wire that to the daughterboard, let the DB send current to the mainboard, and since this all outputs a lot of heat, now you run into a serious heating / cooling problem. Add a fan, a larger super capacitor to power said fan, and well, you now have something that looks like a bomb lol.
To touch further on the heat problem - my dash camera has a 10kf SC in it that I wired in instead of the crappy NiCad battery it came with. It was hot enough to keep the snow melted through the windshield on its own with 12v 1a current - roughly 20% of the current the wall charger of the 6p provides. It didn't keep the whole windshield free, rather, a spot large enough to let the camera do its thing without issue.
Thanks Wiltron for your reply. Doesn't seem worth it for me to go through that much trouble to be honest, besides, having something in your car that looks like a bomb these days will get me more attention than I want. I do have to say that I'm able to power the phone with just the charger connected, but up to a certain point, when the cpu spikes while booting it runs short of power and shuts off. Same thing when I'm fully booted into android, I disconnect the battery and it will stay running up to the point where I start some app or even just turn the phone on its side and the phone just goes dark. I'm thinking that the daughterboard does provide power to the motherboard without a battery, but just not enough. Do you think a heftier charger might overload the circuitry of the phone?
cbgreen said:
Do you think a heftier charger might overload the circuitry of the phone?
Click to expand...
Click to collapse
It can provide as much current as normal operations permit, however just make sure the cable and charger are official and supported, like Benson certified cables and a decent quality car charger like Anker.
Don't go crazy with the 50amp 120v brick chargers for cars, but don't grab the cheap ass gas station 0.5a 5v 4 for $10 special either
Tronsmart has good ones - I use one personally that has the certified USB C cable built into it.. minimal issues other than the thing does get hot
Related
Hi!
I had a battery probelm (same one everyone else seemed to get with there 1yr old uni) where it cuts out at 60% due to the voltage from the battery dropping below the threshold really fast.
Anyway I got a new battery .. my old one was 1650ma (or something like that) I got this new one which is 1750ma (or something like that).. definitely different.
Now I plug my original charger (5v 1a) into the pda and the charge light turns on .. I leave it for an hour and the battery hasn't charged any.. in fact its lost charge as you'd expect if it had been left switched on with no supply.
So.. I plug my motorola krzr charger (5v 550ma) into it and go for a shower/sh*t/shave come back and the battery has gained 10%.. great! atleast I can charge it now.
I also have a desktop cradle charger (5v 1a), same problem.. it sits there forever and a day and discharges... no charge.. (I only got it when I got my new battery so could not prove it before hand)
USB charging works with no problems (not from the cradle one though). So my question is ... Why?
Could it be something to do with my new battery?? I got it from PDAAddons and they've always been good in the past so I believe I can rule out it being a fake.
My new battery is a Li-on Poly.. I've got to admit I didn't look at my old one to see if that was a poly too ... was definitely a li-on though.
I can live with using my moto charger on my exec but unfortunately the ac adapter for my cradle is of a different connector type (female pin sleeve thingy like nokia) so before I search the world for a 5v 550ma version I could do with knowing if i'm barking up the wrong tree and about to waste my money..
Any electronics whizzes in the house say ho!
anyone? :''-(
Aahaahaa!
I'm here! Now, what you say sounds very interesting and yet very strange, why?
- Normally more current from the charger should be better, you cannot put in the PDA more current than it's factory maximum (which I don't know how much it is, but that's not a problem), the internal charger (inside the PDA) knows how much it is and how to limit, also takes care of the right charging profile for your battery.
- You don't have to worry about the exact battery type you bought, boths are Lithium, so chargind profiles are mostly the same, these (LiIon and LiPoly) are "exchangeable" usually (I've heard of no problems until now, since several years I mean).
- If your battery is discharging means only one thing, you're not puttin current into the battery, you're taking it out of it! So, either you might have a deffective charger, a deffective charging circuit (the one inside the PDA) or a defective battery.
- You can charge the battery with your Moto's charger, so battery is probably ok, you have used your original charger/craddle until now, so they might be ok, you have charged one battery at least to 10% so PDA should be ok.
What can it be?
Possibilities are:
Slightly deffective PDA's internal charging circuit, the fact that you can charge with a lower rating charger (the one for your Razr, thing that I've done myself two weeks ago), might point to this, because you have already "limited" the maximum current to 550mA (Razr's charger max current).
Slightly different battery, most of the batteries do have some kind of thermal protection circuit inside (chip + temp sensor, etc.), if the behavior of this circuit is not "compatible" somethin strange can happen, however I personally consider this option not to be the best.
One or two of your chargers might also be somehow "deffective", why? Your original battery might be ok and you are just having problems with your chargers or your High capacity chargers (the original one and that from the craddle) have some problem to give enough juice to your batteries.
I surely might proceed as follows:
try to charge both batteries with a stand alone charger, this is not an easy task, because Lithium batteries are the most "delicate" types, charging method is the "strangest" one, I have two stand alone battery chargers that came as gift with some Nokia batteries I bought from an Ebay seller, eventually, I could give you the full schematic so you can construct it (if you want and if you can).
In this way I will not have any more suspects from the batteries.
Second, test each of my chargers, it can be done by connecting a medium -and suitable- load to each charger for some minutes.
A wire wound ceramic resistor should do the trick, ie for the Razr charger (5V, 550mA) I could use a 250mA load, R=V/I, so 5V/.25A equals 20 ohm (1.25W max power, use at least a 2W resistor, 3 or 5W better).
If the internal PDA circuit should be defective, take it to fix or try to fix for yourself.
Hope this helps
kecido said:
Aahaahaa!
I'm here! Now, what you say sounds very interesting and yet very strange, why?
- Normally more current from the charger should be better, you cannot put in the PDA more current than it's factory maximum (which I don't know how much it is, but that's not a problem), the internal charger (inside the PDA) knows how much it is and how to limit, also takes care of the right charging profile for your battery.
- You don't have to worry about the exact battery type you bought, boths are Lithium, so chargind profiles are mostly the same, these (LiIon and LiPoly) are "exchangeable" usually (I've heard of no problems until now, since several years I mean).
- If your battery is discharging means only one thing, you're not puttin current into the battery, you're taking it out of it! So, either you might have a deffective charger, a deffective charging circuit (the one inside the PDA) or a defective battery.
- You can charge the battery with your Moto's charger, so battery is probably ok, you have used your original charger/craddle until now, so they might be ok, you have charged one battery at least to 10% so PDA should be ok.
What can it be?
Possibilities are:
Slightly deffective PDA's internal charging circuit, the fact that you can charge with a lower rating charger (the one for your Razr, thing that I've done myself two weeks ago), might point to this, because you have already "limited" the maximum current to 550mA (Razr's charger max current).
Slightly different battery, most of the batteries do have some kind of thermal protection circuit inside (chip + temp sensor, etc.), if the behavior of this circuit is not "compatible" somethin strange can happen, however I personally consider this option not to be the best.
One or two of your chargers might also be somehow "deffective", why? Your original battery might be ok and you are just having problems with your chargers or your High capacity chargers (the original one and that from the craddle) have some problem to give enough juice to your batteries.
I surely might proceed as follows:
try to charge both batteries with a stand alone charger, this is not an easy task, because Lithium batteries are the most "delicate" types, charging method is the "strangest" one, I have two stand alone battery chargers that came as gift with some Nokia batteries I bought from an Ebay seller, eventually, I could give you the full schematic so you can construct it (if you want and if you can).
In this way I will not have any more suspects from the batteries.
Second, test each of my chargers, it can be done by connecting a medium -and suitable- load to each charger for some minutes.
A wire wound ceramic resistor should do the trick, ie for the Razr charger (5V, 550mA) I could use a 250mA load, R=V/I, so 5V/.25A equals 20 ohm (1.25W max power, use at least a 2W resistor, 3 or 5W better).
If the internal PDA circuit should be defective, take it to fix or try to fix for yourself.
Hope this helps
Click to expand...
Click to collapse
I'm gunna buy another 5v 1a charger .. I've had it reported that this cradle charger (5v 1a) doesn't work properly anyway so it may be 2 seperate problems here Thanks for you advice fella much appreciated
Charging anomaly, workaround
vbJoe said:
...Now I plug my original charger (5v 1a) into the pda and the charge light turns on ..
Click to expand...
Click to collapse
Are you absotively, posilutely certain the AMBER charge light comes on fully?
I leave it for an hour and the battery hasn't charged any.. in fact its lost charge as you'd expect if it had been left switched on with no supply.
So.. I plug my motorola krzr charger (5v 550ma) into it and go for a shower/sh*t/shave come back and the battery has gained 10%.. great! atleast I can charge it now.
I also have a desktop cradle charger (5v 1a), same problem.. it sits there forever and a day and discharges... no charge.. (I only got it when I got my new battery so could not prove it before hand)
USB charging works with no problems (not from the cradle one though). So my question is ... Why?...
Click to expand...
Click to collapse
There is some anomaly about charging with a plug-in charger. You may have to turn the device on so that it can recognize the charger, then close it and let it turn itself off; or perhaps it's turn it off then on, I'm not sure, but I've encountered similar oddities with both 110v, 220v, and 12v chargers, and I've seen discussion about this anomaly on this and/or other fora. Once you get the AMBER light, you're fine (as long as it's putting out at least +5v; +5.5 is better).
I think it has something to do with its looking for a [non-existent] USB signal along with the voltage under some conditions, but not others, but that's just a wild guess. Anyway, I don't think there's necessarily anything wrong with your battery, device, or charger. Hope this helps. Cheers,
Thanks for the reply, I'm 100% that the amber light turns on. Not only that the screen brightens so it definitely knows its connected. I've tried several combinations of turning it off/on etc during the charge/before but nothing seems to make this desktop charger actually put anything in the battery.
Hi guys,
I have really huge problem! When i connect my htc tytn to charger ( wall charger or usb, same thing) it drains battery ! There is orange light like it is charging, but it goes from 100% to 0 in an hour! Battery works fine... 2 - 3 days... and because i can't charge it over usb, i am using nokia charger, cut the wires, took battery out and connect + to +, - to - and that's how i charge it for the last few days! Does anyone has any idea why is this happening? I have wm 6.1 pays rom i think it is 3.05
Fire Hazard
i warn angst doing this as this could over charge the battery and when a Lithium Iron or Polymer is over charged they burst into flames or explode and spread nasty toxic chemicals every where. if this be the case it may be time to try a new rom and see if that fixes your problem, try someone elce's charger if this wont fix your problem it may bet time for a new mainboard as these have the charging circuit built in
lithium rechargeable are compact high energy storages devices, and if not charged properly become dangerous
I had charging issues with my 8125 - it would charge with the charger, but when I unplugged the charger (it would read 100%, say I charged from 52% to 100% or something), it would drop really low to like 25% or 23% - sometimes it dropped all the way, and I could no longer get the battery to charge because my travel charger was 500mA and the original charger was 1A - it didn't have enough power.
I had to give it a boost by using a 9V battery and twist ties - touching the battery like you are doing here. I did it for 15 seconds a couple times, popped it in, and it had enough juice to start charging. However, I wouldn't want to do this too long on it as the battery got warm pretty quick and I saw a glimpse of smoke at one point.
After being cautious and not letting it lose charge all the way again, after a few charges it seems to have improved. It no longer drops battery power when unplugging and seems to work as it should.
Not sure if yours drops when you unplug it like mine was, or if it steadily drains while plugged in. Anyways, I thought my charger was just wacked, but it is working fine now after a few charges and being careful and keeping a close eye on things....I also thought it was the battery, but I ordered a new OEM battery, popped it in, and when I unplugged the charger that battery dropped and lost power as well. Now I have two batteries and both seem to work ok, but I did have to play around with them a lot and it did take a few charges before they started working like they should again. I'm not sure what was going on, because it couldn't have been the battery (I replaced it with a new one), and now the charger is acting properly.
Granted, this is all with an 8125 which is older, but there may be something in common here. All I know is it does seem to be fixed and it didn't require any additional purchases or replacements.
sounds like the charging circuits are wacked, this could be caused by dry joints on the charger "smart" chip, but a little heads up with Li-Ion, they don't like gettin wet, (sweat included) once they have been wet they become a fire hazard, (ultramag69 help me out here, remember that one you gave me that was full of mud?!?).
they also don't like going below their threshold voltage of 2.1v per cell, (i think 2.1 for now) after that the battery becomes a resistor and is not worth trying to shock back into life with a 9V battery, as these have a protection circuit built in, as well once in this state they become another fire hazard, it may be worth buying a cheap $30 butane soldering iron with surface mount attachment and just going over some of the areas located round and on the opposite side of the battery, every thing under the silver covers is RF shielded and not worth trying to reflow.
just don't keep the heat on too long, as you may and will desolder components on the opposite side of the board.
other than that if the charger is giving +5 volts respective to its ground, its fine, the difference between the 1A and 500mA chargers is the rate at which its charges the battery, slower is better for Li-Ion due to battery construction for the life span of the battery (if you get more than 6 months out of one your doing good by manufactures standards)
heck even try checking the phones USB connector, it may be stuffed or shorted
Bought one of these guys to hardwire a charger in my car:
http://www.mountguys.com/product_p/mfx5v-b-micro.htm
On the charger is specifies 5V 1500mA output. Is that ok? I know it's more than stock, but I thought circuitry can step it down if needed.
Also, I'm thinking I want to hardwire to the always hot lead that goes to the radio memory function. Any chance of current problems? Don't think it will drain my battery if I leave it charging while shopping (or at the bar)
Thanks.
I'm curious why you chose to hardwire it, when the device can only pull 700mA, and these little wonders work perfectly.
Nice! Got one of these also... twice the ports and 5X the price:
http://www.amazon.com/Griffin-Powerjolt-Dual-Universal-Micro/dp/B0042B9U8Q/ref=pd_cp_e_2
Yours and mine above specify 1A... this one:
http://www.amazon.com/Charger-Samsu...96/ref=sr_1_15?ie=UTF8&qid=1318442293&sr=8-15
2.1 A.
I just wanted a cleaner look in a little sports car... the hardwire is going to come out the panel and go straight to a dock. But now I'm worried that 1500 mA could be troublesome?
It won't be troublesome, just useless.
I have a setup for my iPod that utilizes one of what I linked. I've got a USB+RCA-to-dock cable running into my center console, then into a port in there, to some empty space in front of it (under the trim, totally invisible) where my audio guys spliced a new line into the RCA jacks that came from the factory, and split off another power line. The charger's in there, cable connects to the ports... It's nice and clean.
this should be fine. the amperage rating on a charger just tells what it is capable of if requested. it is up to the phone itself to provide the requested amount of current. that is to say if this charger can provide 1500mA, but our phones can only use 750mA, your good. it is provided all the current it needs. now on the other hand, if you were charging some device that could use 2000mA(unheard of) this charger would provide all it could, the device would just charge slower.
the voltage is fine. most chargers are rated at 5v, and should be spot on as long as it is a decent brand from a trusted source. a knock off may be out of spec to what it is rated. that is where you could run in to trouble with frying a phone.
anyway, besides all that, this seems risky. not hardwiring a charger to your car, but leaving it there while you are shopping or in the bar. ever heard that an ounce of prevention is worth a pound of cure? id hate to come out of a bar to a broken window and no phone...
i never leave my phone unattended outside of my home.
austin420 said:
some device that could use 2000mA(unheard of)
Click to expand...
Click to collapse
iPad, TouchPad, Galaxy Tab 10.1...
Guess I'm a noob.. very detailed answer in FAQ.
http://forum.xda-developers.com/showthread.php?t=802711&highlight=voltage+amps+charger
Now to find out if those pins are shorted...
Has anyone looked at the following product for wireless charging (ala Powermat)?
It doesn't look like it outputs a lot of power, but for overnight / sitting on the work desk type of charging, it may be adequate.
www dot seeedstudio dot com/depot/wireless-power-supply-p-701.html
Would be interesting to see if it could be nicely integrated into a phone cover.
I think I will order one to play with even though I am not a developer or a hacker or anything like that!
I've seen charging coils like that hacked into existing devices. There are also, on the horizon, self contained batteries that have the inductive charging built in - upgrade any device to wireless charging! (any device with enough volume to justify making such a battery, anyway)
This definitely could work quiet well for that sort of application. I think it is a bit larger than you would hope but if you put a usb connector on the end I think it would work really well.
Yap, but there are limitations.
Loss of energy
Less efficiency
Low amp ratings
Interference
Bulky.
Goods are
Wireless
No need of conectors that opens to external world( for devices with built in coils)
No connector problems like damaged port,loose contacts etc.
Sent from my HTC HD2 using xda premium
giritrobbins said:
This definitely could work quiet well for that sort of application. I think it is a bit larger than you would hope but if you put a usb connector on the end I think it would work really well.
Click to expand...
Click to collapse
That is the $64 problem! Trying to get USB connectors without the need to butcher an existing USB cable. Ideally, I would like to have a double ended USB connector - a male microUSB to plug into the phone, and a female micro or mini USB on the other end - to allow a USB cable connection between the phone or external charger. I know that I could buy from Digikey a male micro USB connector, and a female connector. But these connectors do not come with casings, so any use of them probably wouldn't look pretty without many hours of thought and effort.
I am assuming (without having this charger in my hands with the specifications) that I would probably need to have one or more diodes in-line with the receiver wires to stop external source current entering the receiver and possibly damaging it.
I haven't read up on Li-Ion cell phone batteries and how to keep them efficient. So I don't know whether these batteries can live long term on low current charging, or whether they would need higher current (as from manufacturer provided chargers) to provide efficient long term output.
Induction charging is being used in several applications already, like WII remotes and such. The problem is, as stated above ^^^^ I'm not really sure how lithium ion batteries stand up so such charging, (almost trickle). I know that the batteries used in Wii remotes are Nickel Hydride though.
DMPinBC said:
That is the $64 problem! Trying to get USB connectors without the need to butcher an existing USB cable. Ideally, I would like to have a double ended USB connector - a male microUSB to plug into the phone, and a female micro or mini USB on the other end - to allow a USB cable connection between the phone or external charger. I know that I could buy from Digikey a male micro USB connector, and a female connector. But these connectors do not come with casings, so any use of them probably wouldn't look pretty without many hours of thought and effort.
I am assuming (without having this charger in my hands with the specifications) that I would probably need to have one or more diodes in-line with the receiver wires to stop external source current entering the receiver and possibly damaging it.
I haven't read up on Li-Ion cell phone batteries and how to keep them efficient. So I don't know whether these batteries can live long term on low current charging, or whether they would need higher current (as from manufacturer provided chargers) to provide efficient long term output.
Click to expand...
Click to collapse
I have heard rumours of the device killing batteries. It would be interesting to see how much of the power actually gets to the unit. The wireless power supply you linked in your OP shows a rating of 300-400 mA. That means the average battery would take 3-4 hours to charge from dead if all that power was indeed making it's way to the battery. Not really a trickle charge is all that power makes it to the battery.
All lithium ion battery assemblies have built in circuitry to prevent overcharging, overheating, and possible explosion/fire. The charge circuitry will turn off when fully charged and there's no penalty for topping off a LIon battery without discharging. Hacking a USB cable isn't all that complicated although may not be pretty depending on how well it's soldered together. There will always be a lump in the middle of the cable where the connections are made but you could use sleeving to hide it.
I tried an OEM non branded wireless charger, and after 6 hours of charging, my iphone's battery only increased around 20%...
Anyone tested this on Desire HD?
Anyone know if this will work/has tested on a Samsung Vibrant? Thanks.
I think this technology is still young, probably in 2/3 years it will be improved in its energy losses...
gebedias said:
I think this technology is still young, probably in 2/3 years it will be improved in its energy losses...
Click to expand...
Click to collapse
I don't think time is going to make it more efficient. I think the trend in industry right now (specifically the WPC) is to define a standard, places where you would use wireless power are places where there is plenty of power.
There are a bunch of different companies that make wireless power solutions. I think that the best would be to hack together a QI compliant receiver to the USB port on your phone and then use any QI compliant mat for the transmitter.
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.