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Battery Life Management Questions from a Smartphone Newbie

Hi everyone, I am a pretty technically savvy person, but a newbie to the world of smartphones. I just got a MT4GS this week and have been getting used to it for the past few days. My main concern is the battery life - understandably, compared to my old feature phone, the smartphone is going to use a lot more juice. I just wasn't expecting to charge it overnight, have it plugged most of the day at work, and still be down to ~70% power by the time I get home. I'm not even doing anything that intense with it. It worries me to think that my phone might die on me if I'm out somewhere for the day. And what is the point of having a phone that can run programs and do all these great things, if you're afraid to use it?
After reading around here, I've already picked up a lot of great tips: I ordered a set of the Anker batteries (my phone was purchased used, and while it is physically in great condition, who knows about the battery), and I installed the 2x Battery app. I've reduced my screen brightness; turned off background data; turned off GPS; and when I'm on WiFi, I have 4G off, and vice versa.
A couple of questions:
1) Without doing anything crazy to the phone or default OS, is there anything else you recommend doing to conserve battery life?
2) In 2x Battery, there is a setting "Pause when WiFi on." The description here is kind of confusing, and I can't tell if it's working or not. If I want the mobile data connection off when connected to WiFi, do I want this option checked or unchecked? Right now I'm connected to WiFi, but it appears that mobile data is on whether this box is checked or not.
Thank you so much for all the great info so far, and for any advice you can offer me )

Well, firstly, good call on the anker batteries. I have one, and it's changed my life with this device. I went from being exactly as you described (scared to go somewhere without knowing exactly where my next source of power was) to not paying it much mind.
Secondly, if you are unrooted stock - then you have a whole lot of apps working in the background and conspiring together to drain your battery. ...and there's nothing you can do about it because both T-Mobile and HTC saw fit to place them there, running around the clock and beyond your control.
This is known as bloat, and on this phone it's beyond out of control. It's out of control on other phones, but they took it to a special place of exasperation on this one.
I am not sure about this 2x battery app you're speaking of, i've never used it. Consider this, though, it's one MORE app running on your device and draining your battery - and if you are stock this may be something you can ill afford.
As far as the wifi/data dance, this is nothing more then a feel-good measure that really isn't doing anything for you except adding to your interaction with the device. The time your screen is on to make that change takes more battery use then you would save on several hours of having one or the other switched off.
Check this link below (another XDA post):
Everything you wanted to know about Li-Ion batteries but were afraid to ask!
...and it may help you out with battery care.
For me, running my custom ROM with an anker battery and all the apps/widgets I prefer to use I can get 6-8 hours out of a charge on the anker battery with semi-steady usage.
This is with both wifi, mobile data and background data on, and the screen on but at mostly dim brightness for 4-5 of those 6-8.
If I overclock the processor to 1.7Ghz (stock it stops at 1.2Ghz) and hook it up to a television using a playstation (game console) emulator...running flat out at full speed I can drain the (anker) battery in as little as 3 hours.
Something that may interest you as time wears on and you get used to having the anker batteries and using them is what is mentioned in this thread:
external battery pack! Awesome!
...and there are many out there and good deals to be had on some, poke around a bit and you'll find one suitable if such is your desire.
One last thing to consider - make sure you are using the proper charging port.
Most USB ports on computers only push half an amp, as well as nearly every single secondary port on chargers (think car chargers with an 'extra' USB port). Half an amp is not enough current to charge the device if being used, and barely enough to see positive battery increase if not.
Make sure whatever you plug into is pushing 5volts 1amp, or you'll see your battery level continue to drop as you are charging.
(oh, and GPS is something you WILL see more battery life from turning off if not using - so having something like a soundhound app widget on your home screen with location on will eat your battery before you know it's gone by activating the GPS.)
Dimming the screen if possible will see you the greatest gains in battery life, and then getting rid of any apps you can that are running in the background is the next biggest step - but again, if stock and unrooted there is only so much you can do on app management.
DON'T USE TASK KILLERS - EVER. (they do much, much more harm then any falsely perceived good you may think you are getting from them.)
Recap:
Screen = biggest battery drain.
GPS chip/use = second biggest drain.
Apps in background = third biggest drain.
Wifi/mobile data = negligable drain.
Hope this helps a bit.
Edit:
Oh, and welcome to XDA!

Blue pretty much covered everything that I was going to say. I also have the Anker battery, and I also have the Anker 5600 mah external battery, and I no longer have battery worries. I choose the Anker external battery over the other ones because of its small portable size, even though some of the other ones have more capacity. I find that I can get about two full charges of my phone with it, and it is small enough to fit in my pocket or purse with no problem. I highly recommend an external battery just for piece of mind, knowing that I no longer have to be searching every place I go for an outlet. I love that I can charge my phone while it is in my pocket or purse. Also the price isn't too bad, I bought mine for about $40, but I see Amazon now has it for $33. I bought it from a company called Laptop Mate on Amazon, and it was shipped amazingly fast even though I just got standard shipping. Laptop Mate then said if I wrote a review I could choose a free gift. The gifts were not anything spectacular, but the gesture was nice. At the time I could choose between a usb powered reading light, a card reader, and I forget what the other one was. Again nothing great, but it was just a nice bonus, I will definitely buy from that company again. So with my Anker internal battery, and my external battery, I could reasonably not have to plug my phone into the wall for at least two days, I could stretch it more if I was camping or something. I really like keeping my screen at full brightness, so that is where most of my drain comes from. Well, sorry for the long winded response, and welcome to XDA. I bet that in a month you will wonder what you ever did with out a smart phone.
http://www.amazon.com/Anker-Externa...on/dp/B005K7192G/ref=pd_rhf_gw_cpp_tab0_p_t_1

Thank you so much for your very thorough responses! I am happy to report that since making a few little changes (turning down my screen brightness, turning off the background data sync), performance is already noticeably better. Yesterday I was on battery power for close to 14 hours, was on and off WiFi, talked on the phone probably a couple hours total, and used it what I would consider a "normal" amount (e-mail, photos, some social networking)... and still had ~50% power left by the time I went to bed. That is much more reassuring to me, and I can only assume performance would get even better once I get those new batteries.
I understand about the "bloat" and having all these extra things running, but I think doing anything with the ROM is a little above my expertise at this point. For now, things seem to be working reasonably, so we'll see...
I like the external charger idea, but I am going to hold off for now. I ordered the 2-pack of Anker batteries, so once I get those, I'll have 3 batteries. One should be fine for a normal day, and if I'm really going to be out for a while and not have any opportunity to recharge, or will be using the phone a lot, I could just bring along a spare or two. (Good thing I am a lady with a purse - what do guys do?! Carry a man bag? My husband is considering getting the same phone, so this is a valid concern.)
I'm apparently too new to post a link to 2x Battery, which I've seen mentioned elsewhere on this board, but that's the name if you want to look it up in the Android Market. Even if it is using a little more battery power, I think it's worth it. It puts controls for things that use battery power all in one place, and it makes it very easy to monitor the current battery status. I think I'll stick with it, at least until I get a better sense of how my use affects the battery.

Per the question of a man hauling batteries, I just carry a spare battery or two I'm my front pocket. If I am carrying keys I will slap a piece of tape accross the terminals to prevent a short. One or two guys carry their spare gear in a camera case. I can haul most all I need in a corner of my Levi's front pocket.
I also used to run Juice Defender, it got irritating waiting for the data connection to spin up and the benefits were outweighed (IMHO) by the downsides. Killing data every time the screen turns off was grim.
Hastily spouted for your befuddlement

I have a zipper case I keep the phone in, and it's not much larger then the device itself. Above and beyond keeping dust out ( primary function ) it also has a small pocket on the outside I keep a few knick-knacks in, like a retractable micro-usb cable, backup memory card ( recovery purposes) mini flash drive and spare battery.
I highly recommend some kind of small zipper case for the device to keep out the dust, best $10 investment I've made for the phone.
Not in a position to link pics at the moment, but I'll do so over the next few days when I get the chance - especially floating loose in a potentially dusty purse it's something to consider.
I wish the video cable was something I could cram in to it as well, but that presents too much bulk for it to work, I have a mini camera case I carry sometimes with the A/V cable, AC adapter, another micro-usb cable and some memory cards and flash drives - something to consider for yourself for carrying cables and such since you most likely have room in your purse for a mini camera case with such things.
Sent from a digital distance.

Thanks for all the carrying tips!
Blue6IX said:
I highly recommend some kind of small zipper case for the device to keep out the dust, best $10 investment I've made for the phone.
Not in a position to link pics at the moment, but I'll do so over the next few days when I get the chance - especially floating loose in a potentially dusty purse it's something to consider.
Click to expand...
Click to collapse
I'm not really worried about my own phone, it has its own little pocket inside my purse, and I don't know what kind of ladies you hang out with, but my purse is not dusty...

Please forgive - I meant no offense by it.
I threw in the word potentially because while I have seen some pristine purses, i've also seen some which haven't been vacuumed out in a long time, if ever. The very fine dust that gets in during the course of normal travel is what our enemy is here. (...and yours may be vacuumed out on a consistent basis, really only you can know.)
This need not just be dirt, even the fibers of the material wearing off in tiny fractions of an amount from simply carrying it around (material rubbing against material as it's shape stretches, bends and contorts) is enough to be a hazard to the device. Over time this adds up.
(though, saying it has it's own pocket/pouch within the purse itself lends a good deal more protection and paints a much better picture then the previous blanket statement of 'in my purse')
Due to the slide mechanism and the exposed back of the LCD screen it is very easy to get dust under the screen, in between the layers of it.
Slide it open with the screen at max brightness, then flip it over. Look at the very end of the slide channels on the screen side, from an angle on the side. You will be able to clearly see the light shining through opposite the T-Mobile branding on the backside of where the genius button is. Look past the greenish tint and see the whitish light, noticing how it extends inwards.
You can now look at the other side, right by the T-Mobile branding in the same spot and though you can't see the light shining through, you can see how very fine dust can work it's way in between the digitizer and screen.
'Dust under screen' is something that people who post here at XDA have made warranty exchanges over, as well as who knows how many who don't post have done. It's a valid exchange gripe that is in fact covered under warranty from what the people who have posted about it have led us to believe. There are also plenty of 'dust under screen' doubleshots on reduced price on ebay that you could look up this very moment.
Again, I meant no offense, but was simply trying to use the situation presented to illustrate a potential hazard your new device could fall victim of. Hopefully by bringing it to your attention you can take steps to minimize any damage, or at least present you with the opportunity to later be in a situation of:
'Oh well, at least I knew it was coming'
...as opposed to:
'Wow, I wish I knew that could have happened'
We only wish you to get the best experience possible from your Android, and while there is a lot of important info here...'tis easy to become overwhelmed by it all and miss some of the important things that could help you immediately, or should be known immediately.
Glad to hear you are already in better straights over the management of your available power!
By the way - thanks for endeavoring to clarify the app you were using for battery management, i'll definitely scope it out when I get a chance.

Blue6IX said:
Please forgive - I meant no offense by it.
Click to expand...
Click to collapse
None taken, I just thought it was funny
Thanks for the tips about dust, though. That wasn't something I had really considered, though I'm hoping to get a bit more life out of this phone than my last few (cheap, and switched on a whim), so I'll be sure to keep things clean. Is it ok to spray the back of the slide-out with some compressed air, or could that cause other problems?

Little update:
I did use a little compressed air to clean out the back of the phone, so hopefully I didn't hurt anything.
Two different cases are on their way to me - I'll see which I like more and return the other.
I've had the Anker battery in for just a couple hours, and it's already amazing! I've been using the phone a decent amount, turned on notifications and everything I'd switched off, and it's still at 100%! Also feels much cooler than the other battery. It was a tight fit, like everyone said, but I did get it in and fit the back cover over it.
But, weird thing: when I turn the phone sideways, the screen no longer rotates. It will still rotate if I slide the keyboard up, but otherwise it's like it doesn't recognize that the orientation changed. Did the battery mess something up?

The screen didn't rotate on it's own unless you slid the keyboard out if you are using the stock launcher - you may have made the same mistake I did in thinking it was so, but it wasn't.
Home screens, in the app drawer...etc... not made to auto-rotate.
You just happened to finally realize it - same thing happened to me.
I even argued against it, and couldn't figure out why it was changed.
A while later while I was going through the code that comprises Rosie (sense launcher) I actually saw that it wasn't made to do so.
So no, the battery didn't mess this up, it's the way it was supposed to be.
The reason for it is there is an alignment issue with some widgets when it switches from portrait to landscape in Rosie. I'm not sure how to fix it the way they have it coded, i've been scratching my head on this one for a while and tried a few things with no success.
HTC could learn a few things from some aftermarket app designers ( like the team that made GO launcher, for instance)
The way they built it, I don't think it's possible to fix their mistake, it's too interwoven and embedded in the design of the code.
Edit - it still and always has, autorotated while you are in apps themselves if they support it.

Oh you're right! That's funny, I never noticed before. In other apps, the screen does rotate normally, so I guess all is good...
Going on 12 hours with this battery, with all notifications, synching, etc. turned on, and I'm still at 67% ... And this is right out of the box, without the 4-5 cycles they recommend. I'm very happy with it so far!

How much pressure can a screen take? Can I rest my head on it?

Not as weird as it may seem
At night I listen to music/radio while I go to sleep. I use a cheap phone at the moment but was thinking about getting a 2012 Nexus 7 that I can use for this (and actually use it as a tablet as well)
Will it be okay if it's under my pillows or will the weight/pressure damage the screen?
Thanks in advance :good:

technicalnoobxda said:
Not as weird as it may seem
At night I listen to music/radio while I go to sleep. I use a cheap phone at the moment but was thinking about getting a 2012 Nexus 7 that I can use for this (and actually use it as a tablet as well)
Will it be okay if it's under my pillows or will the weight/pressure damage the screen?
Thanks in advance :good:
Click to expand...
Click to collapse
Lol your tablet will be fine haha unless you're head is the size of 3 watermelons and weighs 50 pounds then but seriously it won't cause any problems

the question is more about how much damage will the mobile make to your head if the wifi/cell network is running trough your head all night?
except you run radio by earphone receiver with airplane mode on..then never mind

crzykiller said:
Lol your tablet will be fine haha unless you're head is the size of 3 watermelons and weighs 50 pounds then but seriously it won't cause any problems
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Click to collapse
Thanks
deprite said:
the question is more about how much damage will the mobile make to your head if the wifi/cell network is running trough your head all night?
except you run radio by earphone receiver with airplane mode on..then never mind
Click to expand...
Click to collapse
How much damage will it do?

You should be fine. Did that on a plane once, the biggest damage was the droll lol.

technicalnoobxda said:
Thanks
How much damage will it do?
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Click to collapse
well there is no official study about that as far as i know..
just know for myself that i sleep better with airplane mode on and all the network stopped

technicalnoobxda said:
Not as weird as it may seem
At night I listen to music/radio while I go to sleep. I use a cheap phone at the moment but was thinking about getting a 2012 Nexus 7 that I can use for this (and actually use it as a tablet as well)
Will it be okay if it's under my pillows or will the weight/pressure damage the screen?
Thanks in advance :good:
Click to expand...
Click to collapse
I use a quality speakerpillow, it has a long enough lead that I don't risk the phone/tablet and I can rest directly on the speaker and keep volume low and not disturb my partner.
Sent from my A210 using Tapatalk

Better sleep, huh?
technicalnoobxda said:
Not as weird as it may seem
At night I listen to music/radio while I go to sleep. I use a cheap phone at the moment but was thinking about getting a 2012 Nexus 7 that I can use for this (and actually use it as a tablet as well)
Will it be okay if it's under my pillows or will the weight/pressure damage the screen?
Thanks in advance :good:
Click to expand...
Click to collapse
Ha ha... That is really a funny question. But it should be answered. It won't damage your phone unless you move the pillow below your head above your tablet. Use a good cushioned pillow though.
And yes, do turn the airplane mode on. Radiations are not good for your brain. (I'm not expecting more such questions :laugh Just kidding brother.
Ohhh God. Why are we discussing about it? Doesn't it come with Gorilla Glass?

Probably you will have to worry not tossing the phone down to the floor while you sleep.

why you just don't do that and but your phone beside your below

Just buy a quality pillow speaker , then you dont have to worry about getting tangled up in headphones cables aswell

I really wouldn't worry about it for clarifications sake and a technical answer to your questions your main concerns would come from the stress your head would apply to your phones screen. More particularly the relation between the compressive force your head creates and the maximum compressive strength of the material in question before failure of that material under load. (Stress= F/A) The Nexus 7 uses Corning Gorilla Glass which has a maximum compressive strength of 800 MPa. That's 224,808.944 pound-forces per meter^2 and your head does not exert anywhere near that number.
Like I said you really have nothing to worry about you won't damage your screen by laying it under your pillow.

I'm surprised no one brought up the very real possibility of overheating. Sure, you can rest your head on it - but you're smothering it under a pillow and not allowing for the heat it will generate to dissipate.
It would be especially bad if you were charging at the same time - and either way not something I'd recommend anyone do. Why shorten the lifespan of your device by exposure to high internal temperatures if there are other options (like using it with a pillow speaker instead).

Or you could get a wireless headset?

NFC Tags

Hello guys.
I was thinking about getting some NFC Tags to set up around my house. For example, one at the main door so that when I leave it changes my Nest thermostat to Away mode and turns off Wifi on my phone.
I know it's possible, but I'm not sure what to buy. There are so many options, 64k, 128k and apparently for specific phone brands.
What should I get for the N5 and for my intended use?
Thank you!

fedecape said:
Hello guys.
I was thinking about getting some NFC Tags to set up around my house. For example, one at the main door so that when I leave it changes my Nest thermostat to Away mode and turns off Wifi on my phone.
I know it's possible, but I'm not sure what to buy. There are so many options, 64k, 128k and apparently for specific phone brands.
What should I get for the N5 and for my intended use?
Thank you!
Click to expand...
Click to collapse
Pretty sure any one will do lol

The size doesn't really matter because nfc commands barely take any memory. However, I read that Mifare tags don't work with newer phones like the N5.

Cranberry juice

What would happen to my phone if I completely submerged it in cranberry juice? I'm trying to pass a Chem class and the professor wants me to do something impressive with my phone since he sees me on it all the time. I showed him Cyanogenmod and the like but he's not fazed. He's like, 75 and doesn't understand computers. I don't know about the electrical capacitance of berry juice so I was wondering if I put my myTouch 4G Slide in a clear bucket of cranberry juice whether or not it would still be on while in the juice.

AndrMatr said:
What would happen to my phone if I completely submerged it in cranberry juice? I'm trying to pass a Chem class and the professor wants me to do something impressive with my phone since he sees me on it all the time. I showed him Cyanogenmod and the like but he's not fazed. He's like, 75 and doesn't understand computers. I don't know about the electrical capacitance of berry juice so I was wondering if I put my myTouch 4G Slide in a clear bucket of cranberry juice whether or not it would still be on while in the juice.
Click to expand...
Click to collapse
You would fry your phone. Nothing you do will be able to impress him as his point is that you shouldn’t be on it in class. Mainly with that device. There is not alot you can do. Maybe remotely login to your home pc. Thats about it. Also Showing him CM is not really impressive. They are turning into the running joke of the android world.

zelendel said:
You would fry your phone. Nothing you do will be able to impress him as his point is that you shouldn’t be on it in class. Mainly with that device. There is not alot you can do. Maybe remotely login to your home pc. Thats about it. Also Showing him CM is not really impressive. They are turning into the running joke of the android world.
Click to expand...
Click to collapse
Well, isn't that a little discouraging?
Maybe I could submerge it in colored mineral oil since it doesn't conduct electricity? I saw some PCs submerged in mineral oil on Youtube.
And how is CM the "running joke of the Android world"? What are you using, MIUI? Or homebrew?
And he honestly doesn't care that I'm on it. He says, "It's your grade. Do what you want." and I have an A+ anyway. He just wants me to do something cool.

AndrMatr said:
Well, isn't that a little discouraging?
Maybe I could submerge it in colored mineral oil since it doesn't conduct electricity? I saw some PCs submerged in mineral oil on Youtube.
And how is CM the "running joke of the Android world"? What are you using, MIUI? Or homebrew?
And he honestly doesn't care that I'm on it. He says, "It's your grade. Do what you want." and I have an A+ anyway. He just wants me to do something cool.
Click to expand...
Click to collapse
Have you been watching the tech news about CM? Check it out and you will know. No I don't use miui they are right there with cm.
As for something cool I guess you could try a remote login to your pc to recover missing homework or something of that nature.

zelendel said:
Have you been watching the tech news about CM? Check it out and you will know. No I don't use miui they are right there with cm.
As for something cool I guess you could try a remote login to your pc to recover missing homework or something of that nature.
Click to expand...
Click to collapse
I mean, yes, CM has screwed up a little in the past few months, I agree, and the weird shenanigans with OnePlus were a little sketch, but I don't think it's worth criticising.

AndrMatr said:
I mean, yes, CM has screwed up a little in the past few months, I agree, and the weird shenanigans with OnePlus were a little sketch, but I don't think it's worth criticising.
Click to expand...
Click to collapse
Have you seen their latest of wanting to take android away from Google? Do they not realize that if Google stopped pushing code to aosp they would die off completely. Then adding in untested code that causes tons of issues, forcing some of their developers to close source their apps so they can make money off of it. Yeah they deserve it. To the point that main aosp based roms have stopped using their sources and are ditching their theme manager.

AndrMatr said:
What would happen to my phone if I completely submerged it in cranberry juice? I'm trying to pass a Chem class and the professor wants me to do something impressive with my phone since he sees me on it all the time. I showed him Cyanogenmod and the like but he's not fazed. He's like, 75 and doesn't understand computers. I don't know about the electrical capacitance of berry juice so I was wondering if I put my myTouch 4G Slide in a clear bucket of cranberry juice whether or not it would still be on while in the juice.
Click to expand...
Click to collapse
Assuming you have done a unit on electrochemistry....why not make a battery to charge your phone.

justmpm said:
Assuming you have done a unit on electrochemistry....why not make a battery to charge your phone.
Click to expand...
Click to collapse
Ah, I see what you mean, but no, we haven't yet. I guess I could do the thing this gal did here:
https://www.youtube.com/watch?v=9_LLj4_3ZRA
This might win.

AndrMatr said:
What would happen to my phone if I completely submerged it in cranberry juice? I'm trying to pass a Chem class and the professor wants me to do something impressive with my phone since he sees me on it all the time. I showed him Cyanogenmod and the like but he's not fazed. He's like, 75 and doesn't understand computers. I don't know about the electrical capacitance of berry juice so I was wondering if I put my myTouch 4G Slide in a clear bucket of cranberry juice whether or not it would still be on while in the juice.
Click to expand...
Click to collapse
You could "do something impressive" within the bounds of Chemistry. Dunking a phone in cranberry juice (or any other flavour) isn't impressive at all. I see someone already suggested making a battery...

MiyagiSan said:
You could "do something impressive" within the bounds of Chemistry. Dunking a phone in cranberry juice (or any other flavour) isn't impressive at all. I see someone already suggested making a battery...
Click to expand...
Click to collapse
Look at post #8

AndrMatr said:
Look at post #8
Click to expand...
Click to collapse
Is that what you've settled on?
If so, onions and proper leads can give you an eye-wateringly bigger jolt than citrus fruits... :crying:

Please do not put your perfectly good phone in cranberry juice.... please.
Instead do this....
Get an old charging cable you don't care about (a lot cheaper to destroy)....
and show you can charge your phone with a make-shift battery.
Whatever battery you make I recommend using a diode connected transistor or some kind of a limiter to limit current to your phone so you don't burn it out incase you make some awesome kind of a bad ass battery.
That will impress your professor.
Tips:
You can make a fruit battery out of:
Four lemons (the bigger and juicier the better)
Four pennies
Five zinc-galvanized nails
Five sets of alligator clips
but I'm not sure if the mA would be enough to charge your phone but it will be enough to power a small LED.

TryHardBlueonMac said:
Please do not put your perfectly good phone in cranberry juice.... please.
Instead do this....
Get an old charging cable you don't care about (a lot cheaper to destroy)....
and show you can charge your phone with a make-shift battery.
Whatever battery you make I recommend using a diode connected transistor or some kind of a limiter to limit current to your phone so you don't burn it out incase you make some awesome kind of a bad ass battery.
That will impress your professor.
Tips:
You can make a fruit battery out of:
Four lemons (the bigger and juicier the better)
Four pennies
Five zinc-galvanized nails
Five sets of alligator clips
but I'm not sure if the mA would be enough to charge your phone but it will be enough to power a small LED.
Click to expand...
Click to collapse
Yeah, I wasn't thinking of a fruit battery, more like an old school voltaic pile made out of coins (like pennies) or metal disks from the hardware store. Depending on which metals and electrolyte you use, you should get 0.5V to 1V per "cell". The diode transistor is a super good idea, and you probably will need a voltmeter to determine how many volts your battery is producing and you should also be able to determine the mAmp being produced. Look at the specs of your the charger for your device and just make sure you don't go over the current or voltage specs. My guess is that you will not be able to generate enough current to fully charge your device, so I would leave it off and just try and get the "battery charging" display to light up for a bit. If you go down this route, be prepared to answer some "chemistry" teacher type questions. The more you know the more impressed your teacher will be.

MiyagiSan said:
Is that what you've settled on?
If so, onions and proper leads can give you an eye-wateringly bigger jolt than citrus fruits... :crying:
Click to expand...
Click to collapse
Well, then, I planned to do something with something related to that. I just might use pennies, foamboard soaked in vinegar, and zinc discs.

justmpm said:
Yeah, I wasn't thinking of a fruit battery, more like an old school voltaic pile made out of coins (like pennies) or metal disks from the hardware store. Depending on which metals and electrolyte you use, you should get 0.5V to 1V per "cell". The diode transistor is a super good idea, and you probably will need a voltmeter to determine how many volts your battery is producing and you should also be able to determine the mAmp being produced. Look at the specs of your the charger for your device and just make sure you don't go over the current or voltage specs. My guess is that you will not be able to generate enough current to fully charge your device, so I would leave it off and just try and get the "battery charging" display to light up for a bit. If you go down this route, be prepared to answer some "chemistry" teacher type questions. The more you know the more impressed your teacher will be.
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That's exactly what I was thinking. The fruit trick is used too often and has lost its value.

TryHardBlueonMac said:
Please do not put your perfectly good phone in cranberry juice.... please.
Instead do this....
Get an old charging cable you don't care about (a lot cheaper to destroy)....
and show you can charge your phone with a make-shift battery.
Whatever battery you make I recommend using a diode connected transistor or some kind of a limiter to limit current to your phone so you don't burn it out incase you make some awesome kind of a bad ass battery.
That will impress your professor.
Tips:
You can make a fruit battery out of:
Four lemons (the bigger and juicier the better)
Four pennies
Five zinc-galvanized nails
Five sets of alligator clips
but I'm not sure if the mA would be enough to charge your phone but it will be enough to power a small LED.
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I bought a new phone yesterday, so my old myTouch will be fine to destroy just in case. The camera doesn't work, neither does the flash, or certain other things. I bought it on Amazon for $50.

AndrMatr said:
That's exactly what I was thinking. The fruit trick is used too often and has lost its value.
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Well if you have voltmeter you can set up your pile and try different electorlytes. Typically the stronger the acid and saltier it is the better. So you can try salt water, distilled vinegar, and salt added to distilled vinegar as your electrolytes and record the voltage/cell for each electrolyte...make a nice table, build your (probably 5V battery) explaining how the table helped you choose what kind to build, make a pretty picture displaying the chemistry involved and badda bing...you are done

MiyagiSan said:
Is that what you've settled on?
If so, onions and proper leads can give you an eye-wateringly bigger jolt than citrus fruits... :crying:
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Definitely.

justmpm said:
Well if you have voltmeter you can set up your pile and try different electorlytes. Typically the stronger the acid and saltier it is the better. So you can try salt water, distilled vinegar, and salt added to distilled vinegar as your electrolytes and record the voltage/cell for each electrolyte...make a nice table, build your (probably 5V battery) explaining how the table helped you choose what kind to build, make a pretty picture displaying the chemistry involved and badda bing...you are done
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That's a great idea. I don't have a working camera so I can't take pictures of the process to show you guys...

can i put a new NFC tag on my s5 mini battery?

so you know those tags on the battery that give the phone nfc under the label?
basically the one on my battery is broken meaning that i have no NFC capabilities anymore long story short my conspiracy theorist friend said "its the government spying on you with this chip" and then proceeded to slice the chip with a blade and cut the bit that connects it to the battery meaning its just stuck on the battery and sliced but not connected to the battery as it was (part of the tag going inside the top)
from what i can tell that chip gives my device nfc and does not infact give the government any information i was wondering if it is possible to buy another nfc sticker tag thing apply it and then connect it to the battery to give myself nfc again.
i've already ordered a new battery off Samsung but if i can fix this one it would be a huge bonus because then id have a backup battery that has the nfc capabilities back

You'll find better results by asking here:
http://forum.xda-developers.com/galaxy-s5-mini/help

Make your idiot friend buy you a newer better phone
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