Charger question. - General Accessories

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.

Related

Highest output car charger

Is this the highest?
http://www.seidioonline.com/product-p/pmc.htm
Post links if you know of higher ones, thank you.
Sent from my ADR6400L using XDA App
There are 2.1A usb adapters, but I don't think microUSB can take advantage of it. The one you linked is a 1A, which is the same as the wall charger HTC gave with the phone. I'm currently using a 1A usb adapter in my truck.
Ok that's probably what I'm looking for then. Are there wall chargers greater than what came with the phone that I can take advantage of?
Your best bet would be to try the USB adapters made for iPads. The Apple products can utilize the 2.1A chargers with their sync cables, but I'm not sure if a microUSB cable can though. I have some 2.1A wallchargers from some of my Apple products, I'll test them later and let you know what I find out.
http://www.verizonwireless.com/b2c/...ryDetails&archetypeId=12299&accessoryId=46370
I just got an Enercell from Radio Shack with dual usbs. Max output is 2.5A divided between the two ports.
http://www.radioshack.com/product/index.jsp?productId=11329448
on sale now for only $14.99. Seems to be of good quality.
The Motorola rapid chargers rock.
Guys, unless you mod the usb adapter 5V spec, you aren't doing squat with a "high power" adapter. The device has an input impedence that will draw a certain amount of current at 5v., and that's it.
Standard battery: 1400 mAh
Time to charge: 4 hrs (according to manual)
That's 1400/4 = 350 mA.
Most adapters on the market spec more than that, they're usually 500 mA or above. And again, unless you boost the volts, you're not going to be able to push more than 350 mA or so.
So don't waste you're money.
On the other hand, if your going to share a car outlet with another device like mp3 or ipod, then yeah, you'll need a higher output, two port, adapter.
Edit: It just occurred to me that if you're using the phone heavily while charging, then yeah you may need more than 500 mA. My currrent widget shows the phone can draw another 250 mA or so during use. That plus the charge totals to around 600 mA. But depending upon design, the phone may not be able to pull in all 600 mA. A test with a current meter would be real interesting.
The charger shipped with the Thunderbolt is a 1 Amp charger.
If I use a 500 mA charger the Current Widget shows a +450mA charge current. However if I use the 1A charger, I get a charge current of about +850mA.
Given that the google navigation gobbles over 400mA when running, you need a car charger with greater than 500mA capacity of you want the phone to charge at the same time.
Sent from my ADR6400L using XDA App
boingboingbilly said:
The Motorola rapid chargers rock.
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Good to hear, I ordered one today for $11 on ebay. I had heard other people say they liked that one too.
Ecomaniac said:
Guys, unless you mod the usb adapter 5V spec, you aren't doing squat with a "high power" adapter. The device has an input impedence that will draw a certain amount of current at 5v., and that's it.
Standard battery: 1400 mAh
Time to charge: 4 hrs (according to manual)
That's 1400/4 = 350 mA.
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Click to collapse
You're making the incorrect assumptions that the charging rate is constant, and charging is 100% efficient. Li-ion batteries can be charged at up to a 1C rate (i.e. 1.4A for a 1400 mA cell). Add the power drawn by the phone itself, and a 1.8 Amp charger might not be unreasonable (1.8 A is the specified limit for micro USB connectors). Whether the phone will actually do a maximum rate charge, I don't know.
This, from a TI Application Note (Google for SLAA287, board won't let me post links):
A Li-Ion battery charging process consists of three stages:
· Slow Charge: Pre-charging stage using current of 0.1C
· Fast Charge: Constant current charging stage using current of 1C
· Constant voltage charging stage
During the slow charge stage, the battery is charged with a constant low charge current of 0.1C, if the battery voltage is below 2.5V. The slow charge stage is rarely used during the charging process of a Li-Ion battery.
The fast charge (constant current) and constant voltage charging are the most important stages during a recharge process. Most Li-Ion batteries have a fully charged voltage of 4.1 or 4.2V.
The battery is first charged with a constant current of 1C until a battery voltage reaches 4.1 or 4.2V. The firmware continuously checks the charging current by sensing the voltage at the current sense resistor (Rsense) and
adjusts the duty cycle of PWM output from the MCU. The battery's voltage is checked frequently.
Whenever found the battery's voltage reaches 4.1 or 4.2V, the charger will switch to constant voltage charging mode. The battery is then charged with a constant voltage source at a fixed battery voltage of 4.1 or 4.2 V...When the charging current falls below 0.1C, the charging process must stop.
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Monoprice has Cig to USB(1A) chargers and the USB to Micro cables in multiple lengths(I ordered 6' ones) for far cheaper than you will find anywhere else
mike.s said:
You're making the incorrect assumptions that the charging rate is constant, and charging is 100% efficient. Li-ion batteries can be charged at up to a 1C rate (i.e. 1.4A for a 1400 mA cell). Add the power drawn by the phone itself, and a 1.8 Amp charger might not be unreasonable (1.8 A is the specified limit for micro USB connectors). Whether the phone will actually do a maximum rate charge, I don't know.
This, from a TI Application Note (Google for SLAA287, board won't let me post links):
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Click to collapse
very useful, thanks!
walbuls said:
Monoprice has Cig to USB(1A) chargers and the USB to Micro cables in multiple lengths(I ordered 6' ones) for far cheaper than you will find anywhere else
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I second monoprice.
I tried bunch of cig to usb car charger and none matched advertised output... They all showed Charging (USB). I now use AC inverter and it charges just like a wall charger.
eccenpix said:
I tried bunch of cig to usb car charger and none matched advertised output... They all showed Charging (USB). I now use AC inverter and it charges just like a wall charger.
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I suspect you need to find one which properly follows the USB Battery Charging Specification. That link is to the most recent version, which came out on 7Dec2010 (remember Pearl Harbor!). Version 1.1 is easier - a Dedicated Charging Port is indicated by shorting together the data lines (the two middle conductors on a full sized USB connector. By doing so, it indicates the device may try to draw up to 1.8 A of current (although a dedicated charging port is allowed to limit the current to less than that, it must provide at least 1.5 A).
I bought a cheap USB hub with 5 ports, used an exacto knife to cut the traces going to the data lines (the middle two) on all the ports, and then shorted them together on each port. It's now no longer a USB hub, but a USB charger with 5 ports I can used to charge stuff (phone and Bluetooth, quite often). The AC adapter which it came with does 2 Amps. My Thunderbolt says "Charging (AC)" when plugged into it.
So, if you can open up one of your adapters, just solder a jumper between the middle two contacts (make sure they're not connected to anything else).
Just got the Rocketfish premium microUSB at Best Buy and it has a captive coiled cord and a USB port. TBolt says "AC plugged" and reads +670 mA.
Good choice on the Motorola Rapid Charge - I've burned through 3 other cheap car chargers trying to keep my phone alive while using Google Nav and this is the first one to work!
i have the rapid motorola one on amazon
lippstuh said:
i have the rapid motorola one on amazon
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+1 Works great! Battery widget usually shows about +800mA while only charging. Real close to the wall charger

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.
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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.
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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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Click to collapse
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.

6 Volt Charger

Recently bought a camping lantern that runs on a built in 6v 4.5 AH lead acid battery. It also has a USB connector which is for charging cell phones. I initially thought that the USB would be giving off a safe 5v but on testing it turns out that it is 6 volts straight from the battery.
Is this safe to use occasionally while camping? Will that extra 1 volt kill the battery or is there some mechanism inside the phone to regulate that voltage to a safe level?
Good question....hope someone has the answer for you.
Sent from my SCH-I535 using xda app-developers app
executionist said:
Recently bought a camping lantern that runs on a built in 6v 4.5 AH lead acid battery. It also has a USB connector which is for charging cell phones. I initially thought that the USB would be giving off a safe 5v but on testing it turns out that it is 6 volts straight from the battery.
Is this safe to use occasionally while camping? Will that extra 1 volt kill the battery or is there some mechanism inside the phone to regulate that voltage to a safe level?
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Of course there should be.You get more than 6v in a power socket around the house.
Gkikas said:
Of course there should be.You get more than 6v in a power socket around the house.
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No one plugs their phone directly to the wall socket :/ Thats what the charger is for, it only gives 5v to the phone. Just need to know if it can regulate that 6v to a safe level.
*edit. I think no one here would know about the hardware aspects of a phone. Can someone point me to a forum or anywhere where they may know the answer to a question like this?
May I asked how you measured this?
I'd love to check what output my 12v chargers are outputting
TieNN89 said:
May I asked how you measured this?
I'd love to check what output my 12v chargers are outputting
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A multimeter and a stripped usb cable
executionist said:
A multimeter and a stripped usb cable
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ah yeah
My brain has already flicked off for the day LOL
if you use IRC, try the freenode server in the ##electronics channel. they should help you out there. pretty nice ppl in general there.
Sent from my GT-I9300 using xda app-developers app
?
I'm interested as well. Will 6 volts @ 500mAh fry the phone?
Ok, I am an electronic engineer so a few comments.
I have no idea what kind of charging circuit is in our phones, could probably look it up but ..... in my opinion only 10% above 5V is to be considered safe.
Now you are talking about a 6V battery. That battery is not always 6V. A nice example is the 12V battery in your car which is 12.8V when fully charged. Another example are the cells inside our phones which have a nominal Voltage of 3.7V but are charged to 4.2V.
The Voltage they put on those things is the nominal Voltage.
I would check if there is no electronic circuit in that lamp since I would not connect anything directly to a battery at all.
If you go camping I would check this thing coolook pb-2000. Insert 4 x 18650 batts and you can do a couple of recharges. Very good box for the price and you can salvage 18650 from broken laptop batt packs ... but google and youtube a bit before you do that to make sure you do it the right way.
I'm also interested, any news?
You can see the specs of this type of batteries here. The 6V is nominal, as already mentioned above. The maximum noted is 6.9V and TBH, i would be rather reluctant to test is my SGS3 charging circuit likes the idea of being fed with 40% higher voltage than usual.
Are you sure there is nothing in the lantern that would limit the voltage under load? Could be something as simple as 2 diodes in series, in this case measuring the voltage on the open circuit, totally unloaded, with a DMM that barely draws microamps from it, would show the battery voltage. Try drawing some current from it (use a resistor, a USB LED lamp, etc) while measuring. I seriously doubt a self-respecting vendor would setup a USB port on that thing that would potentially output 40% more than specs, really.
PS: if the port is, indeed, fed straight from that battery, i would rather avoid hooking my SGS3 to it. Even though, it would probably survive.
---------- Post added at 07:08 PM ---------- Previous post was at 06:59 PM ----------
lukesan said:
I have no idea what kind of charging circuit is in our phones...
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MAX77686. Good luck finding the datasheet. And good luck trying to guess if there is anything else potentially fed straight from the USB connector. The bottom line is - i wouldn't dare
Solder this to red wire https://en.wikipedia.org/wiki/Zener_diode
OFC you need 5V model
GR0S said:
Solder this to red wire https://en.wikipedia.org/wiki/Zener_diode
OFC you need 5V model
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Not if it doesn't have a resistor in series. And wait. if the battery is at 6.8 Volt and you have a 5.1 Volt zener and it is charging at 1 Amp so you will need a power resistor. You will have a lot of loss of energy because it will go away in heat.
You could use a dc-dc convertor but believe me forget about it and get one of those charging banks where you can put in your own cells.
lukesan said:
Not if it doesn't have a resistor in series. And wait. if the battery is at 6.8 Volt and you have a 5.1 Volt zener and it is charging at 1 Amp so you will need a power resistor. You will have a lot of loss of energy because it will go away in heat.
You could use a dc-dc convertor but believe me forget about it and get one of those charging banks where you can put in your own cells.
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I'm not sure about how practical it would be to be cutting usb cables and wiring zener diodes just to use this lamp....
I think I had a charger that supplied too much voltage (I'm not positive I didn't measure the voltage output or anything), but I can say that the phone did not like it. It would eventually charge somewhat, but the touch screen wouldn't work and would go bezerk if touched lol.
Again I'm not sure how much V it supplied, but I would assume it was more than 6V. It didn't really damage the phones either, I would try it.
Here's your answer, definitively:
6v at the source (the lantern in this case) will probably be 5v or less at the phone because of the resistance in the USB cable itself. The longer the cable is the higher the resistance will be and thus the more voltage you lose to it. Also, the cheaper the cable (the thinner the wires) the more voltage you will lose per foot.
Here's some specs you can plug into THIS VOLTAGE CALCULATOR:
The USB definition specifies up to 5.3v.
Most USB cables will use 30awg wire or maybe 28awg for the better ones.
Depending on which of the sources I've read, some USB cables/chargers use one pair of wires for charging, and some will use two pairs. You can see that using two pairs of conductors drastically improves the voltage transmission but even still, at 28awg over a 6foot cable you're still losing .75v which puts you at 5.25v and well within the USB spec.
So the lantern is fine to use with your phone with your average 6-foot USB cord.
If you're like me and prefer 10-15 foot USB cords in some places you would actually benefit from a 6v or even 7v power supply at the wall. I've found that even on the OEM Samsung wall charger, when I use a 10-foot cable I don't get enough juice to actually charge my S4. With the screen on the battery charge level still drops. The Galaxy Charge Rate app shows something like 500ma charge rate and that's because there's not enough voltage / too much voltage-drop across the long cable. (Radio Shack sells a modular, adjustable voltage wall-wart power supply as well as USB and micro-USB adapters for it. I'm starting to experiment with it and the long cables.)
USB voltage vs charging current
This is an old thread, but I can confirm that my moto G charges at 6v. Apparently the original Motorola charger outputs 5.75v. I hooked up a variable power supply to my phone. The data lines are shorted together to indicate a high current power source is present. The moto G will test load the power supply before settling on a stable charging current. One that does not cause the voltage to sag excessively. When I applied 5v the charging current was approximately 600 mA. At 6v the charging current was approx 1200 mA. The charging current was measured directly on the phone using an app called ampere.
So I conclude that Motorola use this tactic to ensure their phones charge fastest with their chargers. On the up side, its fun watching my phone go from 40% to 100% in 45 minutes

1A Charger

Hello guys,
Just got my Moto 360 today ! Finally!
So I noticed that the supplied charger has an output of 0.55A, but I'm planing to use the 1A usb outlet that's on my custom RCA outlet.
Do you guys think it's too much for the little 0.32A battery of the watch?
Thank you in advance
You could hook it up to a 5v 1kA supply and it would be fine, as long as it's 5v the watch charger will only draw the 0.55a (or w.e.) that it was designed to draw.
v3ngence said:
You could hook it up to a 5v 1kA supply and it would be fine, as long as it's 5v the watch charger will only draw the 0.55a (or w.e.) that it was designed to draw.
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Thanks for the info. What about if it was the device directly instead of the wireless charger? I believe it'd also draw the maximum designed amperage, right? Why is that people recommend to not charge phones with bigger chargers? Do phones draw more amperage than what's good for their batteries?
Thanks again,
Here's a funny thread from the apple folks:
https://discussions.apple.com/thread/2580579?start=30&tstart=0
The first post really analyzes everything and he has valid info, but needs basic circuit knowledge:
Voltage = Current * Resistance
Resistance is a property of the device, just a constant.
So you can see it's just y=mx + b, if you give the right voltage, it will draw the right current.

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