Has anyone used 2amp chargers on the captivate? These are normally found for the ipad since it needs more juice to charge.
The stock charger is rated at .7a while the usb port i think gives out only .5a, any harm in feeding the captivate 2amps?
You don't "feed" a device amperage. It draws whatever it needs, up to the maximum capabilities of the adapter/charger.
In other words, if the device can only draw 1A, and you have a 2A charger... only 1A will be flowing. If you have a 700mA charger, then 700mA will be flowing and it'll just charge slower.
Now, as far as what the maximum charge rate of the Captivate is... I'm not sure.
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the only way batts charge is by amperage...the charger dictates how much current it puts to the device... more is not always better, there is a limit to the batt and the delicate device as well.
If you have a 2A charger its gonna cram that 2A's into that batt... I suppose there may be a current limiter in line somewhere...to safe guard some devices... but the ONLY time a device draws anything is when its using the batt as a source only.
I think USB is .5A if i rem... not very fast.. 1A is nice... made a HUGE diff in charge time on my old iphone vs usb from computer. But slow charging should eek out more run time as it saturates the cell better. seemed to be true even with the LiION batts.
the way chargers get more amperage is a higher voltage... ( the bigger the diff in voltage, the more amperage the batt gets... ) batt voltage is 3.7 on these.... so lets say usb is 5v... that 1A is 6v and the 2A is 7volts... ( im guessing here...) it is possible to cause damage and burn circuits in the phone... now if you had a charging dock and the batt only was charging then maybe.
the more amps the faster it charges...
now if a batt is rated at a high mah...then the phone will only draw what it needs, irregardless of what the bat can potentially "put out"
not true....complete opposite...
the only way batts charge is by amperage...the charger dictates how much current it puts to the device...
I'm sorry, but this is not correct. As someone who's studied electronics courses (myself or anyone else) can tell you. A little research on the internet will also explain it to you.
Volts are the "force" ("push") of electricity, while amps (current) is the flow. It is not true that "the only way batts charge is by amperage" as voltage plays a big role here too. And no, the charger doesn't "dictates how much current it puts to the device" beyond the fact that it has a maximum. The resulting current is a combination of all factors in the electrical circuit/loop. A device that only needs 500mA to charge is only going to draw 500mA from a charger, regardless if that charger is 700mA, 1A, or 2A.
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more is not always better, there is a limit to the batt and the delicate device as well.
There is absolutely no harm in using a charger that can handle a higher current with a device that won't draw all of it. Voltage, however, is another matter... that is "push" from the electrical source and it can cause damage.
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If you have a 2A charger its gonna cram that 2A's into that batt...
Absolutely incorrect.
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the way chargers get more amperage is a higher voltage... ( the bigger the diff in voltage, the more amperage the batt gets... )
I'm sorry, but you're demonstrating a huge lack of knowledge about electricity here.
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now if a batt is rated at a high mah...then the phone will only draw what it needs, irregardless of what the bat can potentially "put out"
Again, you show that you really don't understand the the technology. "mAh" is entirely different than "mA". "mAh" is "milli-amp hours". It's the amount of electric charge transferred by steady current in one hour. It's a unit of electrical charge. "mA" is just "milli-amps" which is a unit of current.
Basically, a charger will "push" a certain number of volts and can handle a certain number of amps.
I have to agree with sremick, connecting a charger that has a higher maximum current draw to a device will not harm the device. The device will charge the battery with what current it needs or the maximum, if the devices can draw more than the maximum.
Connecting a charger with a higher output voltage could cause damage to the device unless the device has a way of lowering the voltage, like laptop power supplies, televisions, or other electronics that can operate on outlets in the US and some European countries.
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amperage is the difference as i stated.... these batts are 3.7 volts... charging at 3.8 volts is very slow... as the diff of voltage is almost nothing...
the only way they will charge faster is a HIGHER voltage... thus will be a HIGHER diff of voltage....= more amps..
so your gonna tell me, I have a 20A charger sitting here...hook up a batt pack that the bats are only going to draw what they need??? I dont think so. batteries are dumb, they do what they are told. If they cant handle the current, then they will pop...
lets look at rechargeable AA's there are 14 hour, 8hr, 2hr, 30min, 15, min.. all the same damn dumb battery right? 2400mah... the difference between the charge times is the voltage, the shorter the charge time, the higher the voltage, the higher the voltage= higher Diff of voltage = higher Amps.
ok i admit when i said diff of potential... that is a voltage only equation... my bad. been a while..
I have been racing R/C professionally for 10+ years, went to college for Electronics, and was a nextel technician repairing the boards on them and sprint.
In rc, bats are huge, in electric racing, we would cram 10A in the packs versus 6A.. we got to choose, the battery didnt tell me NO!... Its dumb remember? the charger would put out a higher voltage on the leads to create the higher Amperage...
Like I said before there was a big difference on my iphone between using USB and The stock 1A wall plug.. but your telling me It dont matter... maybe you need to go back to school...
You may have been doing RC for a while, but unfortunately your understanding of electricity is severely flawed.
As I'm not interested in getting into an "is not!" "Is to!" debate with you since you seem unwilling to follow even the few links I gave you, I'll leave it there. Another person has already agreed with me that your understanding is wrong... we'll see if anyone else has the energy to also tell you the same thing despite your refusal to listen.
Cheers...
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Some more information for those reading and want to learn more. This reply is not a responce to ANY of the previous posts except the original post, so no responce is needed. Just some additional information from a Engineer with master's degrees in Electrical and Mechinical Engineering.
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Short answer: the two amp charger won't hurt the phone, plus it also is highly unlikely it will charge any faster on this particular phone.
The preceding discussion applies to "dumb" chargers and batteries (which ShannonPricePhoto pointed to a few posts ago). Increasing the charge voltage causes the battery to draw more current depending on the state of charge. The trick is we have both a smart charger and a smart battery in his phone. Lithium-ion batteries actually contain circuitry to prevent them from being overcharged inside the battery.
The cell phone industry has agreed on a worldwide standard cell phone charger as follows: it uses a micro USB connector (not a mini USB) they all charge at 5 V, the smart controller for charging the battery is inside the phone, and it determines how much voltage the battery receives during the charging cycle. (Not the charger, like a dumb charger used to charge a car battery, which changes its output voltage)
The standard allows for charger supplies ranging from 300 milliamps to 1 amp, and the phone can actually inquire what the capacity of the charger is through the USB data line.
Reading the standard makes me wonder if using the larger charger would allow the phone to take advantage of the full 2 amp capacity of the charger. One post indicated that older devices that were not covered by the cell phone standard may likely have charged quicker with a two amp charger, but I seriously doubt your phone will because it wasn't designed to do so. This however is an educated guess. One way to really find out is get two chargers and compare by measuring the actual current?
Now that the basic principles of electronic engineering have been thrashed out, can anyone actually answer the OP with practical advice rather than theory?
i actually would like a good car charger one.... found out today, that if my screen is on, and just the screen not using gps or anything... an hour trip it only went up 1% on charge. the other day i was using gps and iheart radio and it drained the phone on a two hour trip while plugged in.
I "thought" it was a 1A since it was for the iphone (griffin) ( and did great with the iphone and gps )
leaving the screen on at home, stock charger, the %'s go up pretty good...
have a link to that 2a you found?
Well while the cigarette plug to USB adapter has the 2A capabilities, plugging in a standard USB to MicroUSB cable is probably not going to get you there. You're going to need to use a charge-only USB cable.
You might be onto something...
been testing diff chargers...
so far the STOCK one seem BY FAR to charge the fastest.
most 2A chargers are dual, and it means 1A for each slot. fail.
using my ipad charger is even not the fastest.( you would think that would be the fastest )
now all but the stock charger & one from wal-mart do not ask me how i want to connect to USB, mass storage, Kies,....
I think the phone will kick in a current limiter if it senses USB a limits it to .5A
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Yes I did try several times, using the Apple charger from my wife's iPad. The Captivate acts weird while under charge from the iPad charger. Things hang, very jittery operations. Even the unlock screen was acting up, did not allow for me to swipe my pattern several times.
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Originally Posted by sremick
You may have been doing RC for a while, but unfortunately your understanding of electricity is severely flawed.
As I'm not interested in getting into an "is not!" "Is to!" debate with you since you seem unwilling to follow even the few links I gave you, I'll leave it there. Another person has already agreed with me that your understanding is wrong.
Cheers...
And I'll add my voice to that. It's the LOAD that determines how much current is drawn, not the source. The source only sets an upper limit on it when it reaches the maximum current it can provide. So, for example, if your cellphone draws 450 ma while it's charging then it will get 450 ma whether it's connected to a 1A source or a 2A source.
The more interesting question is this: if I connect my tablet, which requires a 2A source, to a 1A charger, will I overheat or damage the charger? I'm an electrical engineer, and depending on how they designed it there are many different possible outcomes:
1. it might automatically shut down and produce NO output
2. there could be a drop in voltage.
3. along with the drop in voltage there could be a loss of filtering - the nice smooth 5V DC could turn into 60Hz pulsed DC, which could cause all sorts of weird consequences.
4. The charger might overheat and fail, potentially even causing a fire or damage to the tablet.
Has anyone used 2amp chargers on the captivate? These are normally found for the ipad since it needs more juice to charge.
The stock charger is rated at .7a while the usb port i think gives out only .5a, any harm in feeding the captivate 2amps?
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Last edited by Drivespinners; April 8th, 2012 at 01:33 PM.
Thanks for all the useful information here.
I'm interested in the same question from a Galaxy Nexus point of view... checking it's okay to use a 2amp car charger with it.
Some good links, if anyone can post them, to provide references to the above would be really useful if anyone's got any...
This thread has a lot of nonsense mixed in with the sense. Trust the engineers, who generally understand this stuff. Theory aside, here is some data: I charged my Motorola Razr Maxx HD with two different chargers, the one that came with the phone (rated at 5.1 volts, 850 mA) and one from an iPad (rated at 5.1 volts, 2.1 A). In both cases I used the USB cable that came with the phone (it plugs into the phone with a microUSB connector). The battery in the phone is rated at 3300 mAh.
Using the stock charger from 43% full to 70% full, I got 811.5 mA, which is 95% of the nominal 850 mA.
Using the iPad charger from 51% full to 87% full, I got 1114 mA, which is 131% of the nominal 850 mA, but only 53% of the nominal 2.1 A for the iPad charger. The phone did not get warm during this process.
So there is definitely some current limiting both in the phone and in the charger. And if you want to charge a bit faster than the stock charger allows, you can do it with a higher-power charger (rated at the same voltage).
2amp usb chargers?
