Develop Bugs

[Q] Wall charger question

So i just sold my old blackberry curve and along with it the wall charger i used for my MT4g
so i looked around my house for another corded wall charger as the plug-usb cable combo just doesnt work for me as the cord is way too short for my needs
well i found an older Moto wall charge PN# SPN5334A...it has the same basic specs are the mytouch plug part with the Input: 100-240~200mA 50-60Hz...but the output is 5v 550mA instead of the mytouch plug being 5v 1A
so the question is...will the different of almost a half an amp cause any serious issues other than maybe a slower charge? any potential for damage to the battery or phone or even the charger?
well any help would be great...thanks

No it wont hurt the phone, only way to damage it is to over amp, as in say it was 2.5 amps but however it will slow the charge down I recommened going to a a store that sells computer stuff and picking up a usb extension cord I got a 3 foot on mine and dont see any draw backs as I do with a under amped charger

f1vel66a said:
No it wont hurt the phone, only way to damage it is to over amp, as in say it was 2.5 amps but however it will slow the charge down I recommened going to a a store that sells computer stuff and picking up a usb extension cord I got a 3 foot on mine and dont see any draw backs as I do with a under amped charger
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yeah i never really considered extending the usb cable...i actually have a 6 ft extension cable sitting in my drawer
but i appreciate the info

No problem hope it helped
Sent from my HTC Glacier using XDA App

f1vel66a said:
No it wont hurt the phone, only way to damage it is to over amp, as in say it was 2.5 amps but however it will slow the charge down I recommened going to a a store that sells computer stuff and picking up a usb extension cord I got a 3 foot on mine and dont see any draw backs as I do with a under amped charger
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What's over amp? If the voltage is correct, the higher the amperage the more efficient it(charger) is, as the phone will draw as much as it needs to charge, in this case around 1amp according the factory charger.
Matching voltage is the important part. Too low of amperage will result in slower charge or no charge when using and plugged in at the same time.
[via XDA premium]

sleepyfu said:
What's over amp? If the voltage is correct, the higher the amperage the more efficient it(charger) is, as the phone will draw as much as it needs to charge, in this case around 1amp according the factory charger.
Matching voltage is the important part. Too low of amperage will result in slower charge or no charge when using and plugged in at the same time.
[via XDA premium]
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All voltage is the force pushing the amps through. Amps is the actual energy. Resistance is a factor too. Check the Watts to see that they match. But don't over amp it as well
Sent from my HTC Glacier using XDA Premium App

I meant there is no such thing as over amp. Amprage rating is for how stout the power supply is. A 5v/2amp supply can charge 2 of these phone with out issues. 500mA will charge but slow. Think of car batteries they are all 12v and the "long lasting" or "performance " ones will have better amp ratings.
Wattage is simply volt x amp, in this case here, volt is the constant.
[via XDA premium]

sleepyfu said:
I meant there is no such thing as over amp. Amprage rating is for how stout the power supply is. A 5v/2amp supply can charge 2 of these phone with out issues. 500mA will charge but slow. Think of car batteries they are all 12v and the "long lasting" or "performance " ones will have better amp ratings.
Wattage is simply volt x amp, in this case here, volt is the constant.
[via XDA premium]
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If by over amp, you mean over charge? Too much amperage causes a lot of problems, just like too much voltage can cause a lot of priblems
Sent from my HTC Glacier using XDA Premium App

sleepyfu said:
I meant there is no such thing as over amp. Amprage rating is for how stout the power supply is. A 5v/2amp supply can charge 2 of these phone with out issues. 500mA will charge but slow. Think of car batteries they are all 12v and the "long lasting" or "performance " ones will have better amp ratings.
Wattage is simply volt x amp, in this case here, volt is the constant.
[via XDA premium]
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I've seen phone batterys blow from to much amps... You can go + .5 amps max on a cell phone before things start to go wrong. And that isnt recommended for to long unless you want battery issues
Sent from my HTC Glacier

So did it happen with a 5volt output charger or something higher? I have seen 8v mini usb charger from Motorola around, that will blow out your HTC battery.
Also can happen if there is a problem with the phones charging circuit, not from a 5v charger with a high amperage rating. Now with a higher amp rating, and your phone has issues, the more amps is available, the bigger "battery blow" you can achieve.
Do I recommend more than 5v/1amp? not really, but can you use a 5v/2amp charger or a 5v/4amp charger if it exists? Yes. Is 1amp safer? kinda.
How do I know this? it was an amperage question I answered wrong at my every 1st job interview 11 years ago.
These guys put it in better words than I do.
sivankls said:
DOESN'T MATTER ..if u know the basic Ohms Law..its the max capacity of the charger.(or any source) the current regulating circuits will take care of the real charging current fed to the battery
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tkteun said:
I charge my phone on my computers USB connection all the time, all computers have a maximum of 500mA USB current.
Amps are pulled from the charger, not pushed to the phone.
Voltages are pushed to the phone, not pulled from the charger.
If the phone draws too much current from the charger, the voltage drops to a point where the maximum power (P (Watt) = U (Voltage) * I (Amps)) of the charger isn't exceeded.
According to the USB specification you need at least 200mA with 500mA recommended +5VDC.
More is never a problem, you could even use a 50A power supply without breaking your phone. Practically spoken: I wouldn't do that.
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High current car charger

Anybody come across a car charger that is high current like the HTC wall charger?

Most car chargers are classified as "rapid".

Anything designed to charge an iPad (2.1A versus the typical 1A) will give you plenty of juice. I use the Scosche reVIVE II with Pandora, Bluetooth, and GPS Navigation all on and still have enough power to positively charge my battery.
Fair warning, though, this will cause the phone to get real hot (I've had the overheating warning lights flash twice so far), so make sure you have plenty of ventilation around the phone, keep it out of the sun, etc etc.

Any charger that is at least 1 amp. will do. The phone 'pulls' a max of around 0.85 amps. No need for more then 1 amp.
If it has a replaceable cable, it must be the heaviest gauge, shortest cable, that you can use. I have seen long cheap thin cables that drop over a volt, and the Thunderbolt charges really slowly.
The charger or cable have to state that they for rapid charging. To rapid charge, you need to have the USB D- and D+ lines shorted. If that are not shorted, the Thunderbolt limits the charge current to around 0.35 amps. thinking it is connected to a PC. If they are shorted, letting the Thunderbolt know it can be rapid charged, you get up there around 0.85. You can easily modify the charger for high rate if it is good for at least an amp.
And in the end is heat. Heat and lots of it. It will damage the battery. So put it out of the sun and in cool air like near a vent.

Motorola Rapid Charger on Amazon is the best. I bought two.
http://www.amazon.com/Motorola-Vehi...Q9CA/ref=sr_1_1?ie=UTF8&qid=1309959388&sr=8-1
Review off Amazon
Genuine Motorola charger in retail packaging. 4.75-5.25V 950mA output, works w/ most micro-USB phones like Incredible, etc., June 11, 2010
By
David Pearlman "sound fanatic" (Arlington, MA) - See all my reviews
(TOP 500 REVIEWER) (VINE VOICE) (REAL NAME)
Amazon Verified Purchase(What's this?)
There are so many sketchy sellers selling phone chargers out there, that it can be a bit scary. The problem is that if the charger is poorly made, the output of the charger can be out of spec and can, in some cases, fry the phone you connect to it.
For that reason, when it comes to phone chargers, you should stick to name brands. (They are all made in China, but the name brand ones are usually subject to stricter QA).
When I found this charger on Amazon, SOLD BY AMAZON, I jumped on it. It's a MICRO USB car charger, made for Motorola and sold under the Motorola name, in retail packaging. The rated output is 4.75-5.25V and 950mA.
This charger should work fine with most any phone that uses the MICRO USB connector. The key number to pay attention to is the second one, the rated amperage. This is the MAXIMUM amount of current that the phone can request from the charger. A typical USB port on a PC provides as little as 100mA, and few provide more than 500mA. So this charger should charge your phone faster than when it's connected to a PC. A few phones out now can use up to 1000mA. But that just means they CAN use that amount. If 950mA is provided, they'll still charge, just a bit more slowly.
Note that the amperage (second number) merely tells you how much the charger CAN supply, if requested. The phone itself is responsible for asking for the current. That is to say, if this charger can provide 950mA, but your phone can only use 300mA--no problem. Your phone asks for 300mA and the charger provides all of what is requested. If, on the other hand, your phone can use 1000mA, this charger will provide all it can, which is 950mA--a wee bit less than the max asked for. That's also not a problem; it just means your phone will charge a little bit (not much in this case) more slowly. The rated voltage for this charger is presented in a range of 4.75-5.25V. The "ideal" voltage for a USB charger of any type if 5V. And most chargers for home use are rated right at 5V. But car chargers work in a noisier environment and thus you have the range. This is where a cheapo charger can really do damage, as some of them are poorly regulated and can provide voltages that are WAY out of spec. Again, when you can get a name brand charger from a seller you can trust (Amazon) for such a reasonable price, it's very foolish to consider the cheapo no-names.
This is an excellent quality name brand travel micro USB charger at a price that beats the no-name junk from third party sellers. What's not to like?
BE SURE TO ORDER IT FROM AMAZON AND NOT ONE OF THE THIRD PARTY SELLERS, as some of those have been known to make mistakes with respect to what they ship relative to the listing. I can confirm that Amazon is shipping the P513 /89143N charger, as pictured.
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ddgarcia05 said:
Motorola Rapid Charger on Amazon is the best. I bought two.
http://www.amazon.com/Motorola-Vehi...Q9CA/ref=sr_1_1?ie=UTF8&qid=1309959388&sr=8-1
Review off Amazon
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I've been contemplating buying this one, but I'd like to ask you if it charges your battery with navigation+music going? I have a usb charger in my truck, and with both of those going it just manages to keep my battery level where its at, sometimes losing a % or two.

kr0n1c said:
I've been contemplating buying this one, but I'd like to ask you if it charges your battery with navigation+music going? I have a usb charger in my truck, and with both of those going it just manages to keep my battery level where its at, sometimes losing a % or two.
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From what I've read in the past here on XDA and on the reviews for the charger (on amazon) you shouldn't have a problem. The second review for the charger on amazon states that the reviewer was looking for a charger which actually charged his phone will using GPS and that he found it. It's a very well built charger and cheap. It's made my Motorola and sold by Amazon so buy with confidence.

kr0n1c said:
I've been contemplating buying this one, but I'd like to ask you if it charges your battery with navigation+music going? I have a usb charger in my truck, and with both of those going it just manages to keep my battery level where its at, sometimes losing a % or two.
Click to expand...
Click to collapse
It does indeed charge. I've had it since my original Droid and was concerned when I updated to the TB but it will charge the TB no matter what you're doing (I've had Nav running while on a phone call with BT and searching the internet and it still showed it was charging). Just be prepared for your phone to get HOT!! Great charger.

worwig said:
Any charger that is at least 1 amp. will do. The phone 'pulls' a max of around 0.85 amps. No need for more then 1 amp.
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Actually, the phone will pull more than 850 mA. You're probably basing that on using a battery monitor, which only shows the flow of current into/out of the battery. I've seen 800 mA into the battery at the same time I have display, GPS and a phone call going, which is definitely more than an additional 50 mA. It wouldn't surprise me if the phone can take advantage of something more than 1A, since I see a battery drain of more than 200 mA with all of that going when not on the charger.

kr0n1c said:
I've been contemplating buying this one, but I'd like to ask you if it charges your battery with navigation+music going? I have a usb charger in my truck, and with both of those going it just manages to keep my battery level where its at, sometimes losing a % or two.
Click to expand...
Click to collapse
I have that Motorola charger and am a heavy GPS user. It charges the battery as if it were plugged into the wall. You'll be very satisfied.

mike.s said:
Actually, the phone will pull more than 850 mA. You're probably basing that on using a battery monitor, which only shows the flow of current into/out of the battery. I've seen 800 mA into the battery at the same time I have display, GPS and a phone call going, which is definitely more than an additional 50 mA. It wouldn't surprise me if the phone can take advantage of something more than 1A, since I see a battery drain of more than 200 mA with all of that going when not on the charger.
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No, that was measured at the 5 volt power supply, based upon a lab power supply. I did a lot of experimenting when I developed the charger and phone mount for my motorcycle. And to get the 850ma from the power supply, I used a very short, maybe 8 inch, USB cable, and a charge voltage close to 5.3 volts. With 5 volts at the power supply, it would only pull about 650ma from the power supply. That was due to the voltage drop in the USB cable. With the 5.3 volts at the power supply, I was getting close to an actual 5 volts at the Thunderbolt. I never measured the current at the battery, but I could see it being a bit more then the 850ma in, if there were a switch mode supply in there.
Though I like the Battery Monitor widget as a rough guide, I never tested to see if the battery current and the battery monitor are accurate.

Does anyone know if the included HTC ac adapter and cable will charge faster than using your pc with the included USB cable?

happimeal said:
Does anyone know if the included HTC ac adapter and cable will charge faster than using your pc with the included USB cable?
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Absolutely.
A PC USB port is limited to under 500ma. The Thunderbolt appears to to limit PC USB draw to about 350ma. I haven't measured the actual current in the HTC charger, but it is a high current charger, and charges my Thunderbolt very quickly. Battery Monitor widget shows high battery charge rates. I suspect it is getting near the max rate up near 1 amp.

worwig said:
Absolutely.
A PC USB port is limited to under 500ma. The Thunderbolt appears to to limit PC USB draw to about 350ma. I haven't measured the actual current in the HTC charger, but it is a high current charger, and charges my Thunderbolt very quickly. Battery Monitor widget shows high battery charge rates. I suspect it is getting near the max rate up near 1 amp.
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HTC charger states 5V/1A on the charger itself.

You can use the Palm car charger for $3.75+tax, free shipping. it is 5V/1A, same rating as the HTC wall charger.
Go here for 25% off
http://www.wireless.att.com/cell-ph...otion/accessories.jsp?source=EC0A0011600jtl10
Add product here, must add to cart to see 25% discount.
http://www.wireless.att.com/cell-ph...027&q_sku=sku4720234&q_manufacturer=&q_model=
Also, if so inclined, you can lop the top off of the charger so that you can use any usb cable (ipod, iphone, anything)

dpham00 said:
HTC charger states 5V/1A on the charger itself.
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That doesn't mean much. That is the MAX the charger can output. The amount that the Thunderbolt will pull varies. If it thinks it is plugged into a USB, it will be less then 500ma. even if the charger is capable of 10 amps.

worwig said:
That doesn't mean much. That is the MAX the charger can output. The amount that the Thunderbolt will pull varies. If it thinks it is plugged into a USB, it will be less then 500ma. even if the charger is capable of 10 amps.
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i have used the Palm car charger, checking with bmw, it shows around 850ma, same as on my htc charger.

worwig said:
Any charger that is at least 1 amp. will do. The phone 'pulls' a max of around 0.85 amps. No need for more then 1 amp.
If it has a replaceable cable, it must be the heaviest gauge, shortest cable, that you can use. I have seen long cheap thin cables that drop over a volt, and the Thunderbolt charges really slowly.
The charger or cable have to state that they for rapid charging. To rapid charge, you need to have the USB D- and D+ lines shorted. If that are not shorted, the Thunderbolt limits the charge current to around 0.35 amps. thinking it is connected to a PC. If they are shorted, letting the Thunderbolt know it can be rapid charged, you get up there around 0.85. You can easily modify the charger for high rate if it is good for at least an amp.
And in the end is heat. Heat and lots of it. It will damage the battery. So put it out of the sun and in cool air like near a vent.
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Click to collapse
um, i am aware that any charger that will do 1A will do. that was my question, what car charger will do 1A. Alot of times, they dont have that info listed on pages that are selling them.
and the whole thing about the D- and D+ shorted together, i do not believe. the HTC cable that came with the phone does rapid charging and i use it for data all the time too. if they D- and D+ was shorted, i would not be able to use it for data transfer. not unless the HTC charger shorts them internally inside the charger.

leoingle said:
unless the HTC charger shorts them internally inside the charger.
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Bingo!!

leoingle said:
um, i am aware that any charger that will do 1A will do. that was my question, what car charger will do 1A. Alot of times, they dont have that info listed on pages that are selling them.
and the whole thing about the D- and D+ shorted together, i do not believe. the HTC cable that came with the phone does rapid charging and i use it for data all the time too. if they D- and D+ was shorted, i would not be able to use it for data transfer. not unless the HTC charger shorts them internally inside the charger.
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Yes, it is hard to find the current info online or even on the package sometimes.
Yes, it is shorted in the charger. I have seen it done in the cable and the cable can't be used for data of course. Not sure why anyone would do that, but they do.

StarTech USB Y Cable *Double your charging speed*

I haven't seen anybody mention this yet here on the forum, so I went ahead and bought one and tried it myself.
http://www.amazon.co.uk/dp/B0047AALS0/ref=asc_df_B0047AALS09152658?smid=A1AUCPBF2P18HS&tag=googlecouk06-21&linkCode=asn&creative=22218&creativeASIN=B0047AALS0
This is a USB Y cable. Two USB type A plugs to increase charge capacity from 500mA to 1A.
I use Siyah kernel with STweaks to change USB charge capacity from 500mA to 900mA, I am currently looking for a way to increase this to the full 1A.
Only £3.99 from Amazon. Tested using CurrentWidget. Charging now at 900mA.

danieljamie said:
I haven't seen anybody mention this yet here on the forum, so I went ahead and bought one and tried it myself.
http://www.amazon.co.uk/dp/B0047AAL...de=asn&creative=22218&creativeASIN=B0047AALS0
This is a USB Y cable. Two USB type A plugs to increase charge capacity from 500mA to 1A.
I use Siyah kernel with STweaks to change USB charge capacity from 500mA to 900mA, I am currently looking for a way to increase this to the full 1A.
Only £3.99 from Amazon. Tested using CurrentWidget. Charging now at 900mA.
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Can't you just buy a 1mA output charger. I have chargers that will fully charger my phone in about 1hr and 30min.
Sent from my SPH-L710 using xda premium

smark72 said:
Can't you just buy a 1mA output charger. I have chargers that will fully charger my phone in about 1hr and 30min.
Sent from my SPH-L710 using xda premium
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It's designed for PC's and Laptops which only output 500mA on their USB ports.

Would work really well with the KiDiGi Cover-mate Dual Desktop Cradle, too bad it is a tad to expensive seeing that it is just a cable

Hey i have this cable which came with my 2.5 HDD external case. In some places i need to connect both cables to power the HDD so you think it will work same with S3? Also will it not damage it?

Exactly what I was looking for
danieljamie said:
I haven't seen anybody mention this yet here on the forum, so I went ahead and bought one and tried it myself.
This is a USB Y cable. Two USB type A plugs to increase charge capacity from 500mA to 1A.
I use Siyah kernel with STweaks to change USB charge capacity from 500mA to 900mA, I am currently looking for a way to increase this to the full 1A.
Only £3.99 from Amazon. Tested using CurrentWidget. Charging now at 900mA.
Click to expand...
Click to collapse
this was exactly what I was looking for.. Thanks a lot.. I also has Siyah kernel, and many USB 2 ports available at work, and like to keep my AC charger at home.

This cable won't give you 1A. I guess the second USB plug has no data connection (how could it? ) and without a registered USB device a USB port gives only a few mA of power.

It does work with 2.5" harddrives that need more power than one USB port can deliver. Why shouldn't it work with the s3?
But why would you need that when you are charging your phone at work? It's not like you're in a hurry. It can sit there all day.
And I wouldn't try to charge it with 1A or more just to save a little time. The charger you get with the s3 an the s3 itself are made for 900mA. That's why the kernel is limited to 900mA aswell. You might damage your phone by charging it with a higher current. Sure, there is a safety margin build in but going to the limit seldom is a good idea.

weisselstone said:
This cable won't give you 1A. I guess the second USB plug has no data connection (how could it? ) and without a registered USB device a USB port gives only a few mA of power.
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This was correctly answered back in August (above). What does data have anything to do with current? It simply has 2 plugs so that it can draw more current (mA).
shamez23 said:
It does work with 2.5" harddrives that need more power than one USB port can deliver. Why shouldn't it work with the s3?
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This.
shamez23 said:
But why would you need that when you are charging your phone at work? It's not like you're in a hurry. It can sit there all day.
And I wouldn't try to charge it with 1A or more just to save a little time. The charger you get with the s3 an the s3 itself are made for 900mA. That's why the kernel is limited to 900mA aswell. You might damage your phone by charging it with a higher current. Sure, there is a safety margin build in but going to the limit seldom is a good idea.
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No, you can't damage it that way. Electronic devices DRAW current, which means that they only take as much as they are able to. You can plug your phone into a 5A charger and it wouldn't damage it. Too much voltage WILL fry it though.

Are you sure about that?
I've read more than once on tech sites that for example the 2A charger of the iPad will charge other devices that come with weaker chargers faster but that they advice against doing that on a regular basis.
I do use industrial Li-ion batteries (18650) on several other devices and the charger I use for those has a switch with witch I can decide if I want to charge them at 500mA or at 1000mA. Reading in forums that specialize on devices that use those batteries and that have users that seem to know quite a bit about batteries and do extensive testing with sophisticated equipment, the general opinion is, that using lower Amps will prolong the lifetime of your batteries and that too high currents can potentially damage them as of course will overcharging them.
http://batteryuniversity.com/learn/article/ultra_fast_chargers
http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
I don't know much about battery technology so I might be wrong. I always had problems to wrap my head around anything that has to do with electricity and electronics in general and have to use analogies to understand and explain how things work in that area. Those analogies don't always apply completely.
The one I have in this case is the following:
I decide how much I can eat. I can eat at a normal pace until I'm full but I can also stuff myself and eat a lot more than I would normally do in a short period of time. I know that the later is a bad idea and won't do me much good but it is possible.
If you are correct with what you said, batteries could draw a higher current than what the original charger is delivering, up to their limit but that could still be too much and harm them.
I don't know. Now I'm confused.

shamez23 said:
Are you sure about that?
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You have a point. I guess it depends on how well the charging circuitry (in the phone) is designed.
The battery itself won't limit the voltage/current (*). It's the charging circuitry that does this. For instance, if you connect the battery directly to a power supply and give it too much juice, it WILL damage the battery. Similarly, if the charging circuitry supplies too much to the battery, then this could also happen. However, it SHOULD be designed with appropriate tolerances and safety margins in mind. Therefore, it depends on how much you trust the hardware.
In that way, I guess charging at 500 mA would be considered safer. That being said, I'm happy plugging my phone into the wall charger every night, whether it's 900 mA or 1A.
(*) I know that Lithium batteries usually have built-in circuitry for safety measures, so they MIGHT have something that limits voltage/current, but I'm not sure.

900mA should be save. After all that's what Samsung gave us.
It's just that some people tweak their kernels to 1.25mA or even more. That's quite a bit higher than the specs and probably close to the safety margin.
It won't even charge your batterie faster that way. At least not when you talk about fully charging it. It will get faster to about 80% charge but after that it will take just so much longer to get to 100% that in the end it takes the same amount of time.
I'll stick to the original Samsung charger or the charger of my old HD2 that I have lying around. Makes me feel safer.

Can our phones charge safely from a 6V USB charger?

Like the title says, can the typical smartphone (I'm actually asking for Galaxy Nexus specifically) safely charge from a 6V USB charger?
I'm asking because I want to make an Altoids portable USB charger for my GNex during travels. I've Googled a few results with mixed results. Some people built such a charger with a 4-AA battery setup, which means there will be 6V in the circuitry. However, some people have added a 5V regulator to the setup, while some have not. Those that have added it, sometimes reported insufficient voltage to charge the phone.
Basically, do I need the 5V regulator to safely charge my phone in this particular setup?
I know I can buy such a charger that is mass produced, but I want the satisfaction of a DIY product and appear to be the coolest hipster geek with my Altoid charger

Use Ni-MH rechargeable battery. Their voltage is 1.2V each, resulting in 4.8V in total.
If you use 4 Ni-MH battery with 5V regulator, it won't work. Voltage regulators are only good for stepping down, otherwise there will be improper operation.

I never understood portable chargers...with no disrespect to the OP, why wouldnt you just buy another battery or two? They are smaller and easier to travel around with than a portable charger without the voltage risk of running out of spec.

tincbtrar said:
I never understood portable chargers...with no disrespect to the OP, why wouldnt you just buy another battery or two? They are smaller and easier to travel around with than a portable charger without the voltage risk of running out of spec.
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The spare battery idea is a good one but I think one of the drawbacks to that idea is how to recharge the spares once they are dead. Energizer, Duracell and a host of other battery makers sell rechargeable power packs for not a lot of money.
I would hate to see you build one and have it short and catch fire or damage your phone not to mention the acid leaks from discharged batteries.
Edit. Just saw this in another thread. I bet a lot of us have rechargeable AA's lying around or since the are fairly inexpensive it may be worth picking some up.
http://www.batteryspace.com/battery...ndbeltcliponoffpowerswitch-rohscompliant.aspx

tincbtrar said:
I never understood portable chargers...with no disrespect to the OP, why wouldnt you just buy another battery or two? They are smaller and easier to travel around with than a portable charger without the voltage risk of running out of spec.
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No disrespect taken. Like the ol' fried chicken guy said, where would I suddenly charge my batteries once they're out of juice? I could throw a portable charger in the car, and then go buy some cheap AA's during traveling. If I'm out of country, my charger simply won't even work (I think), due to plug incompatibilities.
Mind you, I have a Verizon Gnex, so I could use all the juice I can get my hands on. Especially during vacations, I'll likely be using the GPS, camera, and various other travel aid apps (Yelp, for one) that would likely drain my batteries a lot faster than I could imagine.
Back on topic: The NiMh idea is a good suggestion, but then I'd only be limited to using rechargables. I've seen the link to that commercially made portable charger before, but my ultimate goal is to go the DIY route. Also, the description of that item has the exact problem I'm trying to tackle, so that one is no better than something I throw together from radioshack and some Altoid tins.

mengsuan said:
Use Ni-MH rechargeable battery. Their voltage is 1.2V each, resulting in 4.8V in total.
If you use 4 Ni-MH battery with 5V regulator, it won't work. Voltage regulators are only good for stepping down, otherwise there will be improper operation.
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Some AAs are 1.2v, while most are 1.5v off the shelf now. It is possible to use a 5v regulator to make sure the voltage does not go higher than 5v to protect your device. If the voltage drops below 5v it will simply stop charging as you need at least 5v +/- 3% or so.
What would be better is if you bought a dc-dc step up converter. This way you can use a single lithium battery (3.7v) or about 3 AAs (4.5v). The step up converter will take that 3-4v and bring it up to 5v or higher (adjustable).
Here's a dc-dc step up converter (http://www.ebay.com/itm/1PCS-LM2577...682?pt=LH_DefaultDomain_0&hash=item3cca94d2ca)
These are what most portable chargers use anyway. They step up the voltage to probably 6-7v? then bring it back down to 5v with a regulator. The reason why they step up the voltage to around 6-7v is to maintain amperage.

http://m.samsung.com/us/mobile/cell-phones-accessories/ETC-CPK008GSTA
what about using one of these to charge the spare. Love mine.
Sent from my Galaxy Nexus using Tapatalk 2

I recently got this because I had a lot of spare eneloops lying around. In 90 mins I get about 20%. For whatever reason when the phone stops charging, I can plug it into my friend's One X and his phone will continue charging where as the Nexus will charge for maybe another minute and then stop, not sure whats going on there but otherwise its a very good product.
http://www.engadget.com/2009/11/12/eneloop-stick-booster-supplies-emergency-power-to-your-portable/

rptw said:
I recently got this because I had a lot of spare eneloops lying around. In 90 mins I get about 20%. For whatever reason when the phone stops charging, I can plug it into my friend's One X and his phone will continue charging where as the Nexus will charge for maybe another minute and then stop, not sure whats going on there but otherwise its a very good product.
http://www.engadget.com/2009/11/12/eneloop-stick-booster-supplies-emergency-power-to-your-portable/
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I was about ready to jump all over that until $40 gave me a slap in the face
I really liked what I read, but I don't think I can justify $40 on it.

rice923 said:
I was about ready to jump all over that until $40 gave me a slap in the face
I really liked what I read, but I don't think I can justify $40 on it.
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34$ and free shipping on ebay, but i actually got it as a gift straight from japan

6V batteries can't make a voltage regulator give out 5V, let alone if you use 4,8V batteries (4x1,2V).
A Voltage Regulator needs to have its input 2,5V minimum above the output voltage (5V+2,5V=7,5V).
You'd be better off (and more stable using either 6 1,5v batteries (or 7 1,2v NIMH) and a voltage regulator.
If you are "too near" of the desired output voltage as soon as the batteries discharge a little the voltage will drop (specially if you use 500mAh batteries) and the phone will no longer charge. Better off being above voltage on the batteries. 6x1.5v=9v, after a lot of discharge,6x1.25v=7,5V will still make the regulator output 5v. (Also don't be "too far" above the voltage or most will be dissipated by the regulator).
You'd be better off using a DC-DC converter which will convert power in any form to the form you wish. Example= 1,5vx500mA=0,75W=5vx100mA (well, allways with some efficiency loss, but way less of voltage regulator).
I've seen different devices, at 5V, charging at different currents. My Samsung will require a minimum of 500mA to charge. My Nexus, with a 1000mA (1A) charger will still discharge (although at a much slower rate than when not connect). Even with the device poweroff you wouldn't be able to charge it with AA batteries.
Or EVEN Better. An external LiON rechargable 7800mAH battery that, fully charged, will charge my Nexus 7 two times

Charger question.

My phone came with a 500ma 5v charger, I seemed to have misplaced it, I have a spare 500ma 5.2v charger at home, Is it safe to use it? Will the extra 0.2V have any adverse effects?
Thanks

Probably OK,
I would say it is OK for most part. Usually, AC/DC adapters are not that precision. You can check voltage output with ohm meter under load for actual voltage output.
Simple way to fix is connect 5v zener diode for quick voltage control between + and -, if your device battery is Lithium battery that is sensitive to input voltage. Check device specification for battery type. You can get zener diode from Radio Shack or electronics part store.

@rhanxdad: good reply but I'm afraid I'm only one of few people in this forum section who understood what you meant Not everybody has EE or electronic hobby background
Here is my take on this. Your battery is 3.7-3.8V, and once you plugin that 5.2V charger into micro-usb (5V standard) interface of your phone conector it depends on tolerance of its input of the internal converter chip (5V -> 3.7V for charging). This can't be guaranteed and will vary between phones, just my guess. Considering your have 500mA charger, I can also guess you don't have the latest brand name smartphone where most of them use 1A-2A chargers. Another thing, everybody makes 5V micro-usb wall chargers, and the fact that you have one rated at 5.2V sounds like some cheap ebay part? So taking all this into consideration, I would probably stay away from that charger. Look up on Amazon, you can find a nice one under $10, like from Anker or Ravpower.

Final Answer
@vectron, yes your answer is better, haha. Sorry about the ambiguous answer.
@aqswde123, How is this, if it is only 5v, then connect to Laptop/PC USB through your Sync cable. You probably already own this and then it will be free.
Good luck.

Thanks guys, will order a new charger and will use my comp to charge it in the meanwhile. After starting this thread I have been googling and I've read that the usual USB tolerance is between 4.75 - 5.25 V and hence anything inbetween is safe, but i wont take the chance anyway.