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Hey
As a possible solution to the low battery life of the G1, I bought a solar panel charger. (http://www.maplin.co.uk/Module.aspx?ModuleNo=229254) To test it, I went and sat in the sun for a while, with a multimeter. When charging an old Nokia, which has a 3.7v battery, the Nokia's battery was drawing about 200mA. Not a lot, but enough to extend the life of the battery if you're out on a walk.
However, when I plugged the solar panel into the G1 (also a 3.7v battery), it only drew 10-20mA. Now, presumably this is due to some sort of charging circuit in the G1. I know some battery chargers have a diode in to prevent back-flow, and they can have a hefty voltage drop on them. Perhaps the G1 has something similar.
My solution to this would be to have a separate connector that will fit between the G1s battery and the phone to supply current directly to the phone/battery. If the phone is using less current than the solar panel provides, presumably the battery will then charge. Otherwise, the phone will run off the solar panel & battery combined, meaning the battery will last longer. I'd not use the panel when the battery is full, so it wouldn't overcharge, and I would put a 10 ohm resistor in to make sure the charging current is fairly low.
Forgetting about the difficulty of creating the connections, does anyone know anything about the manner in which the G1 handles charging that might be damaged by what I'm proposing?
Why do you post in Development section? Becareful when you created new thread in a sub forum!
Thread Move to Dream accessories.
The battery is irrelevant, it's what the charging-circuitry takes as input that matters. (And, regular lithium-cells usually run at 3.7v, so there's no need to check that (Unless it's some special phosphate-based cell, or something fancy))
The G1 takes 5v.
If i recall correctly, Android handles the power-consumption of the charging circuitry when booted. I think it could be regulated from debugfs... But this is dangerous.
(imfloflo: If the above is true, this is indeed Android development...)
For the battery to charge, you need to supply a higher voltage, and i don't know the limits of the voltage-regulation in the device. This could potentially overload it, rendering the device useless (Unless you have the ability to solder smd components, and the regulator is not part of the SoC).
Also, DO NOT try to charge a lithium-based battery without the charging circuitry, you will end up overcharging/overheating it, and that's NOT something you want to happen (If you don't cool it fast enough after this has happened, it will explode, taking the phone, and whatever else is near (Your hand for example) with it.).
Joushou said:
DO NOT try to charge a lithium-based battery without the charging circuitry, you will end up overcharging/overheating it, and that's NOT something you want to happen (If you don't cool it fast enough after this has happened, it will explode, taking the phone, and whatever else is near (Your hand for example) with it.).
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Most Li-Ion batteries have a small control circuit built in.. So unless you take the battery apart and try to charge the individual cells, that shouldn't be a problem.
After I broke the usb socket on my wizard, I used to charge the battery with a plain usb cable chopped down the middle with the wires taped onto the battery terminals.. never blew my hand off once.
Disclaimer: I take no responsibility for any damaged or destroyed limbs resulting from attempting idiotic things like this.
goldenarmZ said:
Most Li-Ion batteries have a small control circuit built in.. So unless you take the battery apart and try to charge the individual cells, that shouldn't be a problem.
After I broke the usb socket on my wizard, I used to charge the battery with a plain usb cable chopped down the middle with the wires taped onto the battery terminals.. never blew my hand off once.
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Click to collapse
Yeah, as dubious as those "clip" usb chargers are, I have not heard of anyone's Li-Ion or Li-Po cellphone battery violently venting as a result of charging past 4.1v. Generally with lithium-based cells, if they have been packaged into a battery then there is probably a basic protection circuit against overvolt, undervolt and shorts.
That said, I would still recommend charging through the mini-usb rather than trying to jury rig together some kind of interface to go between the battery and the contacts.
jashsu said:
Yeah, as dubious as those "clip" usb chargers are, I have not heard of anyone's Li-Ion or Li-Po cellphone battery violently venting as a result of charging past 4.1v. Generally with lithium-based cells, if they have been packaged into a battery then there is probably a basic protection circuit against overvolt, undervolt and shorts.
That said, I would still recommend charging through the mini-usb rather than trying to jury rig together some kind of interface to go between the battery and the contacts.
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Click to collapse
Yes, there's usually protection circuitry built-in, but i'm not going to tell someone i don't know, and therefore don't trust the persons knowledge, to put these circuits to the test...
I've been charging Lithium Ion (Both organic solvent and solid polymer) from my lab-supply several times, without blowing them up, but i have seen what happens when it goes wrong (And it's much scarier to see it in real life, than watch the videos...), and therefore i won't tell someone i don't fully trust to charge a cell without a charger.
Hi Folks
After digging through mounds of tech docs, I was able to verify that the G-Tab uses the TI TPS658621A power management processor for charging.
Good news - you can plug just about anything into it from 9V up to 18V and it should charge it. Theoretically, it should also support step up charging from USB (trickle charge) but I've yet to prove that. (The power management processor supports it, but it might not be in the hardware.)
Bad news - it's just out of reach for a standard laptop charger (19V) so we still need a converter.
So, if you find a connector that fits it, plug it in. Don't worry about the current draw - as long as it's 1A or GREATER it should work fine (the device won't pull more than an 1A, even though our chargers are spec'd for 2)
Technical specs are available here - http://focus.ti.com/docs/prod/folders/print/tps658621d.html
This is awesome info! That means for the car all we need is a fused line to the right plug (center positive of course.)
This is great news, this means that the iGO tip that sends out 19v is safe to be used on the GTab.
Thanks for sharing.
sunglint said:
This is awesome info! That means for the car all we need is a fused line to the right plug (center positive of course.)
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While you might be able to do that, I don't recommend it. If you do it anyway, do yourself a favor and NEVER EVER EVER leave it plugged in while you are starting the car.
From Wikipedia:
A second problem is that nominally "Twelve-Volt" power in cars fluctuates widely. The actual voltage will be approximately 12.5 volts when dormant, (less when cold) approximately 14.5 volts when the engine and the alternator/generator are operating, (more when cold) and may briefly drop as low as 5-6 volts during engine start.[7] DC/DC converters will usually compensate for these small fluctuations.[citation needed]
Rarely, more extreme cases of voltage fluctuation can occur when the car battery is disconnected while the engine is running, or when the car receives a jump start. When the battery is disconnected, a load dump transient can produce very high voltages. A car receiving a jump start from a truck will be subject to its 24 V electrical system.[8] A "double battery jump-start" is performed by some tow truck drivers in cold climates.[9]
Design wise one has to take into account intermittent contact, and voltages outside the nominal 12 V DC like top voltage 9-16 V continuously, top voltage at 20 V during 1 hour, 24 V during 1 minute, 40 V during 400 ms.[10] Protection component tolerance example ratings are +50 to -60 V DC[11] Besides this there's also varying temperatures between -40 till +85 °C to contend with that can affect humidity and condensation.[10] Equipment connected this way must tolerate large variations in electrical- and climate environment.
For more, look at table 20-1 in http://www.fordemc.com/docs/download/EMC_CS_2009rev1.pdf which is reference [10] in the Wikipedia article. Granted, that's very conservative, but a 1A 12V low drop out regulator is cheap insurance for a piece of kit like our tablets.
Interesting. If you plug in tablet and that part number into Google you get lots of familiar looking pictures:
http://www.kitarm.com/news/205-cortex-a9-nvidia-tegra2-tablet-pc-with-10.html (and the photos are marked with this site: http://www.okpbw.com/).
bnovak said:
Hi Folks
After digging through mounds of tech docs, I was able to verify that the G-Tab uses the TI TPS658621A power management processor for charging.
Bad news - it's just out of reach for a standard laptop charger (19V) so we still need a converter.
Technical specs are available here - http://focus.ti.com/docs/prod/folders/print/tps658621d.html
Click to expand...
Click to collapse
aasoror said:
This is great news, this means that the iGO tip that sends out 19v is safe to be used on the GTab.
Thanks for sharing.
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Click to collapse
Did you read the same post I did? His suggestion is that 19V is too high and still needs to be converted.
wd5gnr said:
While you might be able to do that, I don't recommend it. If you do it anyway, do yourself a favor and NEVER EVER EVER leave it plugged in while you are starting the car.
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I agree, and thanks for the info. I do ham radio and already know to not plug things in until the car is running, actually learned that from xda years back from cell phone charging. I also use Anderson Powerpoles for the connections, very highly recommend these. This does mean that given the same precautions I already follow I can make up a nice charging cable pretty easily. And I'll certainly look in to the low voltage protection, just in case.
edit:just saw the call sign, 73s!
well unfortunately I can say that this:
http://www.amazon.com/gp/product/B003MYLLCC
doesnt work
actually it might
it just doenst fit......
sigh
My husband just remembered that we bought a power converter years ago to charge a laptop while traveling in Europe.
Would this work without any problems with the Gtab?
Found the model here: http://www.crutchfield.com/S-jg9JaV...er-Pocket-Inverter-175.html?tab=detailed_info
You mean by plugging in the AC charger to it? Should work fine. The output of the stock charger is about 24W so even if it is grossly inefficient, a 140W power inverter should be fine.
Naturally, I assume no risk, yada yada yada, your mileage may vary, void where prohibited by law.
Hey, if it helps anyone at all, I bought this car adapter from the radio shack and it works well. None of the included tips worked with my Gtab, so I cut the tip off my included wall charger and using two of the adapt-a-plug connectors also available at the shack, I made it so I can use the tip on either my wall charger or my car charger. Just gotta remember to take it with me, and of course get the polarity right. Its a regulated 12 volt charger, so it reduces some of the spikes and drops from the car battery, the amperage is correct, and the on/off switch means you can wait to turn it on until after the car is started. Reduces the amount of plugging and unplugging nicely.
http://www.radioshack.com/product/index.jsp?productId=3889594
I have a power inverter that also has a USB outlet on it for the car. I have also seen an auto adapter that had just 2 USB outlets on it at dollar store. Are these tpes safe to charge the gTab?
LoganFive said:
I have a power inverter that also has a USB outlet on it for the car. I have also seen an auto adapter that had just 2 USB outlets on it at dollar store. Are these tpes safe to charge the gTab?
Click to expand...
Click to collapse
GTab can't be charged via USB
Power Brick
So I apologize for what I'm sure is a dumb question but I don't know squat about electricity.
Will this or will this NOT work with a Igo charger. Deals.woot (today only) has a 90W slimline charger that apparently outputs about 19V. The first post would lead me to believe this will not work while a subsequent one indicates it would.
I'm inclined to believe this WILL NOT work but wanted to check.
greymane98 said:
So I apologize for what I'm sure is a dumb question but I don't know squat about electricity.
Will this or will this NOT work with a Igo charger. Deals.woot (today only) has a 90W slimline charger that apparently outputs about 19V. The first post would lead me to believe this will not work while a subsequent one indicates it would.
I'm inclined to believe this WILL NOT work but wanted to check.
Click to expand...
Click to collapse
Another member reported earlier that he has researched the power management chip on the GTab and it will apparently run up 18v, this justify why many has been using the iGO Asus netbook tip successfully for so long.
Now for the woot deal, I wouldn't bother with a "refurbished" item when you can get the tried and working travel adapter for $18 (shipped) and $20 (for the version with the auto and airplane adapter) there is a confirmed tip that fits the gtab included.
http://www.buy.com/listing/sellerlistings.asp?sku=211343528&buy=0
http://www.buy.com/prod/-igo-40w-un...usb-4-power-tips-for/q/loc/101/219613586.html
Best of luck,
The first post says the top end is 18V by the data sheet. Where have you seen someone quote 20V?
I've been using an iGo netbook charger for 3 weeks without any problem. I found it on sale at Office Depot for $8 the week before they dropped the GTab price to $300. Three weeks is probably only 7 or 8 charge cycles, but I've paid attention looking for hot spots, etc. and haven't noticed anything. I don't love the stiffness of the cable, but it was $8. I'm not complaining.
My only charging "problem" is that the silly thing wakes up when it hits 100% (VEGAn-TAB Ginger). Having the screen come on at full brightness just when I'm falling asleep was funny the first time, but it's getting annoying that I keep forgetting to power it off.
Dan
wd5gnr said:
The first post says the top end is 18V by the data sheet. Where have you seen someone quote 20V?
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Click to collapse
My mistake, I stand corrected, its 18v.
my power adapter plug receiver (male end) on gtablet is bent/broke. is there another option to power?
hopbros said:
my power adapter plug receiver (male end) on gtablet is bent/broke. is there another option to power?
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Click to collapse
the end in the tablet itself, or the end with the wire that goes to the wall?
if it's the wire end, you can get new plugs at radioshack. But requires some soldering skill to get them on there.
or you can get a universal 12-18V / 1amp charger with multiple tips.
Hey all, I was looking into getting a car power adapter for hte G-Tab. I looked on Electroniccrap.com, but everything is usually "out of stock." He sells the iGo systems, which Radio Shack also sells. So, I went to my local RS to see what I could find. They didn't have the iGo stuff, but did have enercell converters/adapters, etc.
As I was browsing, I found 2 12VDC car chargers (if you were curious, the "B" plug fits in the G-Tab). But then I noticed a "150W power inverter." It's a car plug that has 3 AC outlets and 1 USB outlet on it. This is ideal for me becuase I usually charge more than one thing when on long trips, GPS, Zune, NDSi, DVD player, and now the G-Tablet. The issue I'm having is that the back of the package said that it's output was 5VDC, typical of most car adapters. I asked the girl that was working if my AC adapter for hte G-Tablet would do it's own conversion, making it's output 12VDC. She said that it would, and said that each device's AC adapter will convert as needed.
Now, my question, is this true? The charger device does have a fuse on it, and some reviews I read (after purchasing, I know) said that it's worked fine for laptops, DVD players, etc. The main complaint is the hum of the cooling fan that's built in.
I briefly tested it today, with my G-Tablet. The battery indicator said it was 100% charged (but we all know that isn't reliable) I didn't take it out of it's case ot see what color the charge light was, but the charge indicator idn't have the lightning bolt in it, indicating a charge.
Does anyone know if she was telling the truth, perhaps? It's a pretty sweet setup, being able ot use AC adapters for all of my devices in the car, if it works as advertised, anyway. I just couldn't imagine why they would create a charger that has 3 5VDC AC outlets on it...
TJEvans said:
I asked the girl that was working if my AC adapter for hte G-Tablet would do it's own conversion, making it's output 12VDC. She said that it would, and said that each device's AC adapter will convert as needed.
Now, my question, is this true?
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Click to collapse
of course not, how can someone who works in an electronics shop says so ?!
The 5VDC on the package is most probably the output of the USB port on the inverter.
The inverter should output 110 (or 220v) AC @ 50/60 hz, else you wont be able to use your wall plug adapters.
True the GTab adapter will output the proper voltage (12v DC 2A), but its input must be 110v (220v) AC.
My advice is not to use inverters for small hand helds : GTab, GPS, MP3 players .. etc.
Instead, use compatible car adapters, if you need more than one, get a splitter for your socket.
By the way, here is a compatible (and cheap) car adapter for the GTab: http://cgi.ebay.ca/Car-Charger-Koda...ccessories&hash=item51998a1f04#ht_1399wt_1341
Things may be different in Canada, but here in Pittsburgh, PA, just because somebody works at a certain store, doesn't necessarily mean that they know anything about the items they carry.
we actually have a car power splitter, it worked fine in our Honda Element (that the wife hit a deer with) but the Scion XB we have doesn't have much room between the outlet and the shifter lever, so the splitter doesn't quite fit that well. It is adjustable, but we haven't been able to find a position that works.
In fact, we have a car to double USB port adapter right now, that we are powering the GPS and Zune with, even with just the 2 USB cables plugged into it, it's tight.
aasoror said:
of course not, how can someone who works in an electronics shop says so ?!
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Click to collapse
Thanks for the tip - bought one!
FWIW, I'm pretty sure the 'girl in the shop' was simply saying that if you plug your 115/220VAC adapter into the inverter, the adapter will produce whatever it produces when plugged into a wall receptacle, which indeed it should so long as the inverter can produce 24W - and she was just following standard retail practice: 'sell what ya got', and the store *had* an inverter.
Seems like an overly complex way to get 12VDC out of a (nominally) 12VDC system when all you probably need is a regulator.
Another option:
http://www.amazon.com/charger-adapt...OQLG/ref=sr_1_1?ie=UTF8&qid=1307712365&sr=8-1
Only one review, but it's a positive one.
TJEvans said:
Things may be different in Canada, but here in Pittsburgh, PA, just because somebody works at a certain store, doesn't necessarily mean that they know anything about the items they carry.
we actually have a car power splitter, it worked fine in our Honda Element (that the wife hit a deer with) but the Scion XB we have doesn't have much room between the outlet and the shifter lever, so the splitter doesn't quite fit that well. It is adjustable, but we haven't been able to find a position that works.
In fact, we have a car to double USB port adapter right now, that we are powering the GPS and Zune with, even with just the 2 USB cables plugged into it, it's tight.
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When I had my Scion xA, there were two power ports. One as part of the dash, the other was between the two front seats... the xB doesn't have this?
5V won't work. The power management chip is designed to handle 9 to 18V, but any car charger that is 12V out and fits will be fine.
Go to Radio Shack and buy the coiled Universal Accessory Charger. Its regulated 12V dc @ 2Mah.
Mine has been working excellent for months, although i can hear a high pitched sqeel in my audio system when the charger is on with no audio playing. I attribute this to a ground issue, not the charger...
Sent from my G Harmony v2.4 using XDA Premium App
Seems the OP answered his question but I think pointing out a couple of things may be helpful to others.
Haven't met anyone working RS that I thought was stupid but almost none know anything about the electronic components I buy. To think they have vast knowledge of and experience with electrictronics isn't logical.
Most things work with inverters but not all. I have some kind of a power supply, don't recall what, that says not to use it with an inverter. It's true you get 110(110,115,117,120) depending on how it's measured(min,avg,rms or max)) volts out of your home receptical but it's a sine wave. The ouput of a consumer inverter is a square wave.Square waves can cause noise or even overheating in some devices.
The other thing is that to get 110 volts the inverter draws 10X the output current to convert it. With a 20 amp fuse on you cars outlet that means your limited to ~2 amps for your devices.The vehicles system is ~13.5V so that's 27W. If you look at big inverters you'll notice they have battery clamps. 3 AC outlets from a cigarette lighter outlet is way optomistic.
An inverter may be a good choice for occasional use but probably better to keep everthing DC otherwise.
Make sure the inverter shuts itself off if the cars vehicle voltage gets low(i.e.when it isn't running). You could end up with a dead battery or even a damaged one.
rbrainard said:
Mine has been working excellent for months, although i can hear a high pitched sqeel in my audio system when the charger is on with no audio playing. I attribute this to a ground issue, not the charger...
Kind of nitpicking but cars are not grounded. Ground is literally the electrical potential of the Earth. A bad connection on the power or common(chassis) can cause noise but a sqeal is unlikely. The squeal is almost definately the inverter.
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h3llphyre said:
When I had my Scion xA, there were two power ports. One as part of the dash, the other was between the two front seats... the xB doesn't have this?
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It's an earlier XB (2006) and only has the one outlet. When the car is in park, the shifter handle is literally about 5 inches away from the outlet. Having the double outlet plugged in, and angled up (adjustable) will allow some room, but then you are unable to grab the shifter.
I'll be driving to DC next Thursday, and wanted a way to power the GPS, G-Tab, e-cig battery charger, and whatever else my son decides to bring with us (NDSi, DVD player, his iPod touch, etc.)
To JJJustmee: The device does shut off when the car is off, so I'm good there. Also, the inverter itself has a fuse on it, so I assume that if overloaded, then the fuse will give on it, before it effects anything on the car. I don't necessarily plan on running all devices at the same time, more like, run the G-Tablet unplugged until the battery decides to start draining really low. The GPS will be running the entire time. Everything else may be charged for a bit, while other devices are no plugged in. I liked the design of this, becuase the car lighter plug is rather short, since there is a 3 foot wire leading to the AC/USB outlets, like a surge protector. It takes up very little room near the car outlet area. The other options that people posted will not work becuase of the space limitations. I could, and have (in the element) use the outlet splitter, then one double USB outlet, to be able ot handle 3 devices at once, but then we're talking about at least 7-8 inches of plastic pluggs sticking out, and into my shift lever...
JJJustMee said:
Seems the OP answered his question but I think pointing out a couple of things may be helpful to others.
Haven't met anyone working RS that I thought was stupid but almost none know anything about the electronic components I buy. To think they have vast knowledge of and experience with electrictronics isn't logical.
Most things work with inverters but not all. I have some kind of a power supply, don't recall what, that says not to use it with an inverter. It's true you get 110(110,115,117,120) depending on how it's measured(min,avg,rms or max)) volts out of your home receptical but it's a sine wave. The ouput of a consumer inverter is a square wave.Square waves can cause noise or even overheating in some devices.
The other thing is that to get 110 volts the inverter draws 10X the output current to convert it. With a 20 amp fuse on you cars outlet that means your limited to ~2 amps for your devices.The vehicles system is ~13.5V so that's 27W. If you look at big inverters you'll notice they have battery clamps. 3 AC outlets from a cigarette lighter outlet is way optomistic.
Click to expand...
Click to collapse
What you're saying isn't quite true. Min, Avg, RMS, or Max are not accurate figures that you can toss out without testing. The Max voltage of a 120v system is 177v, The Root means square (RMS) would be the nominal voltage or 120v. Regardless, when you say it draws 27w you're doing the conversion incorrectly. The only way to change from one nominal voltage to another is via the resistance. So you max can draw 20A at 12v (240w), or 2A at 120V (or 240w ish) via and inverter (assuming your inverter is sized accordingly).
baenap said:
What you're saying isn't quite true. Min, Avg, RMS, or Max are not accurate figures that you can toss out without testing. The Max voltage of a 120v system is 177v, The Root means square (RMS) would be the nominal voltage or 120v. Regardless, when you say it draws 27w you're doing the conversion incorrectly. The only way to change from one nominal voltage to another is via the resistance. So you max can draw 20A at 12v (240w), or 2A at 120V (or 240w ish) via and inverter (assuming your inverter is sized accordingly).
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Said it for me.
If it turns off as soon as you turn the key off it means the outlet is switched. Will protect the battery but also means it can't be used for anythihng while the car is off. Good or bad depending on usage. What I was talking about is the device being able to shut off when battery voltage goes below, say, 11.6v. Fuse and circuit breakers only protect from too high of an amperage draw. If your system wasn't switched it could still dran the battery. Like if the inverter was left on overnight/weekend.
Sounds like what you're talking about could be ok for a trip. Use the USB as much as possible. Lots more effeceint than the inverter. If you actually mean fuse, get extra. If it's a circuit breaker you'll be good to see what does and doesn't work.
Found one on ebay
Found one here
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=320690673489#ht_4544wt_937
Just ordered it about $12:00 US delivered. I will let you know how it goeswhen I get in about two weeks.
Igo told me a week ago, that they don't yet have a tip for the Gtab/Zpad but expect to do so by the end of the month
Spec
Here you are some pics of Malata official Car adapter. Maybe you can find some thing to help.
Car charger
Just ordered this from Amazon. (can't link yet - crap) so "30W DC/DC Regulated Adaptor for DVD" do your own search
13.34 shipped. Many more bucks directly from batteryspace
Will post again after I test it.
more info: it comes with two tips, neither of which fit the gtab. I had a proper size tip in our tool box so will check voltages tomorrow.
This has better 12V DC regulation than the oem ac charger.
Guys
YOU DO NOT NEED AN INVERTER TO CHARGE YOUR G_TAB IN THE CAR.
ANY 12VDC (output) charger will work. They are a dime a dozen if you know where to look. Just make sure the tip fits, and is tip positive (symbol will look something like this)
12VDC @1A
(-)-C-(+) with a dot INSIDE the "C" that is connected to the (+)
The power supply controller will work down to 9V and up to 18, which is fine for the 10 to 14V you'll get from a car adapter. Just make sure it isn't a step down.
They should be like $5. You might have to bust out the soldering skills though if you can't find the right tip.
The Atrix's default adapter in an 5v = .85A, while the Ipad's is 5v = 2.1A. Is it safe for the battery to use this charger? I also have been using the ipod charger on my atrix too, should i countinue to use the ipod charger or does that have negitive effects too, ipod charger is 5v = 1A
Atrix: 5v = .85A
Ipod/Iphone: 5v = 1A
Ipad: 5v = 2.1A
Typically, a device will only pull what it needs, amperage-wise. The ratings on power supplies are, to my knowledge, always indications of maximum amperage, not any form of 'forced' current. Thus, the only time you need to be worried is if it is lower than your device's required input. You should be fine with either.
+1
That's correct. I actually spent a lot time researching that kind of stuff because I use electronic cigarettes and finding chargers for them was difficult. Anyways, as long as it's 5V it should be fine. They actually make AC adapters that are iPad "compatible", meaning that they are just rated at 2.1A but it still works with the iPhone which the OP has stated uses a lower Amperage.
ian426 said:
Typically, a device will only pull what it needs, amperage-wise. The ratings on power supplies are, to my knowledge, always indications of maximum amperage, not any form of 'forced' current. Thus, the only time you need to be worried is if it is lower than your device's required input. You should be fine with either.
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Thank you, both of you.
Would it charge the same rate?
the fact that a device will pull as much as it needs is true, but that is true only to the devices, appliances, and anything that is using the electricity, not storing it - which is the case with the battery. any electrical device uses only as much power as it needs. for example: a 55watt house light bulb will only use .5 amps, (110 volts AC) even though the circuit is wired for 15 amps max.
When it comes to cellphones, the cellphone is the device that uses the power and the battery stores the power. during charging, battery will try to pull as much in as you will give it, unless there is a limiting factor involved. a limiting factor can be a charger it self, which will supply 1.0 amps, .85 amp max, or what ever the case may be. also there may be a limiting factor built in to the phones circuitry it self that would allow only so much to go through ( i seriously doubt though)
By plugging in to 2.1A charger, the battery will try to intake all 2.1 amps,
Pro: you are charging the battery in half the time.
Con: if it doesn't destroy the battery right away, the lifespan of it and usefulness decreases dramatically.
This is called overcharging the battery, do some research on that and you will find out that overcharging the battery is never a good thing.
2.1A is not enough to destroy the battery right away, but if you would have plugged in 5 or 10 amp charger, it probably would, i'm just saying this to explain the concept.
I personally do use a 1.0A charger that i have left over from previous cellphone (touch pro 2) and your ipod charger should be ok too, but I wouldn't use anything bigger then that.
a small experiment that you can conduct which may or may not work. compare the temperatures of the battery/cellphone while it is charging on .85amp charger and 2.1amp, when it is on a bigger charger, it should get a lot hotter, and that is what destroys the battery.
As far as my knowledge goes, i have taken enough classes about electricity and electronics, and have been working in the field for several years, so i hope i was helpful enough and explained it in simple enough terms for everyone.
hlywine said:
the fact that a device will pull as much as it needs is true, but that is true only to the devices, appliances, and anything that is using the electricity, not storing it - which is the case with the battery. any electrical device uses only as much power as it needs. for example: a 55watt house light bulb will only use .5 amps, (110 volts AC) even though the circuit is wired for 15 amps max.
When it comes to cellphones, the cellphone is the device that uses the power and the battery stores the power. during charging, battery will try to pull as much in as you will give it, unless there is a limiting factor involved. a limiting factor can be a charger it self, which will supply 1.0 amps, .85 amp max, or what ever the case may be. also there may be a limiting factor built in to the phones circuitry it self that would allow only so much to go through ( i seriously doubt though)
By plugging in to 2.1A charger, the battery will try to intake all 2.1 amps,
Pro: you are charging the battery in half the time.
Con: if it doesn't destroy the battery right away, the lifespan of it and usefulness decreases dramatically.
This is called overcharging the battery, do some research on that and you will find out that overcharging the battery is never a good thing.
2.1A is not enough to destroy the battery right away, but if you would have plugged in 5 or 10 amp charger, it probably would, i'm just saying this to explain the concept.
I personally do use a 1.0A charger that i have left over from previous cellphone (touch pro 2) and your ipod charger should be ok too, but I wouldn't use anything bigger then that.
a small experiment that you can conduct which may or may not work. compare the temperatures of the battery/cellphone while it is charging on .85amp charger and 2.1amp, when it is on a bigger charger, it should get a lot hotter, and that is what destroys the battery.
As far as my knowledge goes, i have taken enough classes about electricity and electronics, and have been working in the field for several years, so i hope i was helpful enough and explained it in simple enough terms for everyone.
Click to expand...
Click to collapse
I might have to double check that. There is a chance that there is some sort of limiting circuit between the wall and the charger for the Atrix... I am fairly certain at least laptops do so. I will see if I have a stronger charger and I will check the voltage across the leads in the atrix... if I can.
Its not voltage that you should be checking, voltage should be same in all usb chargers, about 5 volts, you should be checking amps
hlywine said:
Its not voltage that you should be checking, voltage should be same in all usb chargers, about 5 volts, you should be checking amps
Click to expand...
Click to collapse
My mistake... realized that after I posted it.
Also -- I do not have any USB charger that is over one amp, so I cannot check this. If anyone has a mutineer and a more powerful charger, they could do so.
The important factor is the Voltage which is at 5V for both the iPad and Atrix chargers. Whether it is rated at 10W or 5W does not matter because that just reflects the capacity for the current. And the charger is "rated" at 2.1 meaning it can handle that current rather than meaning it will force it. The "draw" of current is decided by the phone itself, as long as the Voltage is identical, the other factors should not matter.
If you read the "Summary" here it will say that, with the iPad charger, you can charge an iPhone which is similar to the Atrix in charging specs:
http://support.apple.com/kb/HT4327
And here are a couple more links:
http://www.youtube.com/watch?v=-ZjRm8nkv9Q
http://munnecke.com/blog/?p=836
hlywine said:
the fact that a device will pull as much as it needs is true, but that is true only to the devices, appliances, and anything that is using the electricity, not storing it - which is the case with the battery. any electrical device uses only as much power as it needs. for example: a 55watt house light bulb will only use .5 amps, (110 volts AC) even though the circuit is wired for 15 amps max.
When it comes to cellphones, the cellphone is the device that uses the power and the battery stores the power. during charging, battery will try to pull as much in as you will give it, unless there is a limiting factor involved. a limiting factor can be a charger it self, which will supply 1.0 amps, .85 amp max, or what ever the case may be. also there may be a limiting factor built in to the phones circuitry it self that would allow only so much to go through ( i seriously doubt though)
By plugging in to 2.1A charger, the battery will try to intake all 2.1 amps,
Pro: you are charging the battery in half the time.
Con: if it doesn't destroy the battery right away, the lifespan of it and usefulness decreases dramatically.
This is called overcharging the battery, do some research on that and you will find out that overcharging the battery is never a good thing.
2.1A is not enough to destroy the battery right away, but if you would have plugged in 5 or 10 amp charger, it probably would, i'm just saying this to explain the concept.
I personally do use a 1.0A charger that i have left over from previous cellphone (touch pro 2) and your ipod charger should be ok too, but I wouldn't use anything bigger then that.
a small experiment that you can conduct which may or may not work. compare the temperatures of the battery/cellphone while it is charging on .85amp charger and 2.1amp, when it is on a bigger charger, it should get a lot hotter, and that is what destroys the battery.
As far as my knowledge goes, i have taken enough classes about electricity and electronics, and have been working in the field for several years, so i hope i was helpful enough and explained it in simple enough terms for everyone.
Click to expand...
Click to collapse
thanks live4nyy, i never saw those before. with all the stuff described there, the only conclusion possible is that each device has its built in limiter on how much it will pull while charging, or apple figures that with a bigger charger your battery on ipod/iphone will still last you past the 1 year manufacturers warranty expiration date, but barely past that date, instead of lasting 3-5 years like its suppose to. what ever the case is with apple, i just hope we have a safety built in into our atrix phones. I guess the only way to find out is to actually check the amperage while its charging.
I'm almost positive that the lithium batteries in phones these days are "rated" for specific current and have built in circuits that dictates the "flow", which is also the same thing that causes the battery to go into a "trickle" charge when near capacity. Just for that there has to be some sort of "regulation" happening. See also here:
http://science.howstuffworks.com/environmental/energy/question501.htm
But I agree, better safe than sorry. If you happen to have an iPad charger that you plan on using let me know how it goes. I'm curious as well.
hlywine said:
thanks live4nyy, i never saw those before. with all the stuff described there, the only conclusion possible is that each device has its built in limiter on how much it will pull while charging, or apple figures that with a bigger charger your battery on ipod/iphone will still last you past the 1 year manufacturers warranty expiration date, but barely past that date, instead of lasting 3-5 years like its suppose to. what ever the case is with apple, i just hope we have a safety built in into our atrix phones. I guess the only way to find out is to actually check the amperage while its charging.
Click to expand...
Click to collapse
I want to make a bike charger for my S3. I made sure the converter is working and can deliver more than 2A of constant current at 5V.
As long as the phone does not detect the converter as a proper charger, it won't draw more than 500mA which is not enough to maintain charge while navigating or using apps. I have tried to measure out the charger that came with the phone and found out that the data lines are shorted. Apart from this, there seems to be no connection from the data lines to the supply voltage. I tried to replicate this on my selfmade charger but still the phone won't draw more than 500mA. I tried searching the net for info on the charging circuit but can't seem to get anywhere. I would like avoid cracking open the original charger.
Does anyone here have an idea what has to be done so the phone will draw more current from a homemade charging device?
you can always get a Kernel with charging control and up the amperage, but that's more of a workaround
There's a reason why i don't like workarounds like this. It violates usb specifications and may lead to damage to a regular usb port if handled improperly. It may be possible that i am missing something. Maybe i'll get another original charger and dig deeper into this matter. I'll post results as soon as available
Noume said:
I want to make a bike charger for my S3. I made sure the converter is working and can deliver more than 2A of constant current at 5V.
As long as the phone does not detect the converter as a proper charger, it won't draw more than 500mA which is not enough to maintain charge while navigating or using apps. I have tried to measure out the charger that came with the phone and found out that the data lines are shorted. Apart from this, there seems to be no connection from the data lines to the supply voltage. I tried to replicate this on my selfmade charger but still the phone won't draw more than 500mA. I tried searching the net for info on the charging circuit but can't seem to get anywhere. I would like avoid cracking open the original charger.
Does anyone here have an idea what has to be done so the phone will draw more current from a homemade charging device?
Click to expand...
Click to collapse
The key in shorting out the data lines to achieve FAST charge rate is that the Phone sees it as shorted at the Micro Usb connection point of the phone. Anywhere else down the line is irrelevant. Depending on the Kernel, most phones slow down the charging rate after...hmmm...anywhere between 70-100%. The closer to full charge...the slower the charge rate gets...until it becomes a trickle charge...just in case you don't know.
If your still having issues, please post back with a more detailed explanation of your wiring and parts as best as you can and I will help you with it.:good:
[Solved] Charger for S3
Considering your suggestions i was asking myself if i've done everything right and as it turned out, i hadn't.
I do know that chargers current depends largely on the charging state of the battery. Good chargers start initiate completely drained batteries with a low current, which is ramped up to the max at around 5-10%. After reaching 85-90% the current drops down to small trickle pulses as the charging finishes. These values can be adjusted within the firmware/kernel to get a longer battery life/more power. That's why i always do charging tests with a battery that is at least down to 33%.
But back to topic now
Using an oscilloscope i found my switching regulator to have about 150mV ripple voltage which apparently is a bit more than the S3 is willing to take. After sorting it out, ie. resoldering a cold joint, it finally works as expected, the ripple voltage is now around 32mV. The regulator could deliver more than 2A before, but only with about 600mV ripple, which i unfortunately overlooked
Charging the phone's completely drained battery, i get around 320-340mA current draw from the battery(12Vnom LiFePO4) .
The phone takes around 950mA at 5.1V. I wonder why earlier charging circuits had to be so "complicated" like with Apple phones or Galaxy Tab, while most newer phones are happy with just shorted data lines.
The circuit i use is composed of a three-phase voltage doubling rectifier, that takes bike from a generator hub in the front wheel. This one is connected to a battery for storage and buffering. A small switching regulator provides 6V 600mA for the lighting system. A larger LM2596-based regulator (you can get those modules around $1.50) provides power for my S3 and a microcontroller that will later be used for monitoring the systems voltages and rotational speed of the front wheel. EAGLE layout files for circuit and PCB will be finished soon.