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I got a better charger!

Discussion in 'Android Devices' started by John I, Aug 8, 2010.

  1. John I

    John I Well-Known Member
    Thread Starter

    As many have noticed the Captivate does not hold a charge very long and the OEM charger is painfully slow. I got my Captivate on release date and have already done the usual to increase battery life (app killer, screen brightness, etc). I have also re-calibrated the battery meter by letting the phone discharge fully a few times.

    A couple of months back I had to buy my girlfriend a ridiculously expensive micro USB charger from Radio Shack (~$25). I decided to test it on my Captivate, since it is rated at a full 1.0 Amp instead of the 0.7 Amp the the OEM charger is rated at. I have been observing the differences in the chargers over the last week or so. Sure enough the Radio Shack charger does charge a little faster, but what caught me by surprise is it seems to charge the battery more fully. When I pull the phone off the battery charger the meter registers "100". The factory charger normally drops to 99 or 98 the moment I take it off the charger and goes down to around 94 within an hour of complete standby inactivity. This morning was the clincher. I woke up and pulled the phone off the Radio Shack charger, showered, ate breakfast, got in my car and drove 3 hours to south Florida. When I got there I checked the phone and it was still reading 100 after 4 hours of standby time!!

    At this point I am thinking that the OEM charger is a piece of cr@p and does not deliver enough voltage to fully charge the battery in the Captivate. I have switched chargers with my girlfriend and will not be using the OEM charger any more!

    Here is the RS charger:
    PointMobl Micro USB AC Charger : Cell Phone Power | RadioShack.com


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  2. TDQuiksilver

    TDQuiksilver Well-Known Member

    Anybody else with similar results?
  3. mesasone

    mesasone Well-Known Member

    I think I have something similar - I lost my blackberry charger and bought a new one (that was waaay too expensive) from Radioshack. I'll have a look at the specs and give it a shot. It's miniUSB but it also has the standard USB plug so I can use the cable that came with the phone.
  4. BigCiX

    BigCiX Android Expert

    I'm going to have to take a look at this. I usually take my iphone with me and waste the battery on that whenever there is a wifi hotspot.
  5. harryzwd

    harryzwd Member

    i believe i have the charger you have linked to and it only puts out 700mA or .7 Amp - same as the samsung wall/usb charger. the radio shack charger is putting out 1000mA or 1 Amp (at the output cable connector, usb is only .5 Amp)

    the standard battery is 1500mAh, i see there are batteries available that are 1600mAh - i wonder if its worth it for the little extra capacity. i mat grab one and see how the phone drains that sucker...
  6. John I

    John I Well-Known Member
    Thread Starter

    The charger I have has two outputs - one built in with a retractable cable and one that uses an external cable. The retractable is rated at 1.0A. The other is 0.5A on the USB connector. Either way I don't think Amps is the whole story here - its voltage. I need to build a test cable to prove my theory, but I think the Radio Shack charger is providing a little more voltage than the OEM charger and thus can provide current to top off the battery that the OEM charger can't. Once the battery has reached the max voltage that a charger can provide the current drops to zero; the phone detects that and stops charging. With a little higher voltage the current still flows and puts more charge into the battery. It could be .5A, that is not what matters. It's the voltage...

    Update: I had the phone connected to my computer trying to get Kies to work for about 25 minutes total yesterday, but it got no other charging other than that. The meter only moved up a couple of points during that time anyway. The meter right now reads 68% full - 24 hours after taking off the RS charger. It didn't get a lot of use yesterday. Mostly standby. About an hour total of 3G surfing, 25 mins of talk, 45 mins of Southpark and Pull Metal Jacket soundboards in the car and 27 text messages.

    John (Electronics Engineer)
  7. artvandalay22222

    artvandalay22222 Android Enthusiast

    I'd be a little worried about the life of the battery. I'm no expert but I would assume that putting more voltage on it, may have an adverse effect on the internal workings of the battery
  8. Jack45

    Jack45 Android Expert

    I'm no expert either, but the one caveat I've read time and time again is to limit output voltage to 5 and that it's the milliamps output that's the important other variable.

    In other words, you could have a higher-rated milliamp charger block and the phone will draw only whatever it needs from that capability. Sorta like making available a full glass of water (1 amp) but only drawing 700 milliamps from that glass.

    I welcome corrections as I don't want to lead anyone down the wrong path.
    artvandalay22222 likes this.
  9. lakergirl21

    lakergirl21 Newbie

    I don't know if this goes along with what everyone is talking about but I took my phone back on Friday to exchange it for a newer one because of the battery problems and random restarting of my original phone. With my original phone I would have the same problem, when it said it was fully charged I would unplug it and it would drop to 98 percent seconds later. Now with my new phone it says fully charged (100%) and stays that way for a while. I'm not using a different charger, it's the same one I've been using all this time. Maybe it has something to do with the battery itself???
  10. smeltn

    smeltn Member

    My phone has been showing 100% for at least a little while until this morning.

    This morning was the first time as soon as I unplugged it from the charger it said 99% instantly. I am not using a special charger, matter of fact I never plug it into the wall, I always plug it into my PC and use the usb for charging.
  11. EricKit

    EricKit Newbie

    Hello, here is what the difference between Voltage and Current (or Amps) is.

    Voltage: Think of it like water pressure. It's how much pressure it's putting on the wire. Voltage will make your phone charge MORE. It's like shoving more electricity into the battery. Now.. does it actually apply?

    Current: Think of it as water flow. It's how much electricity is actually flowing. Amperage will make your phone charge FASTER.

    Hypothetically if the battery was 10V and you put 11V to it at 0.1 Amps verses a charger that did 1 Million Volts and 1 million amps (Assuming no damage could be done), there would be no difference after a certain period of time. After both are fully charged, the battery will only hold 10V of charge (In this case Voltage represents how much electricity has been "shoved" into the battery).

    Now real-world, a higher voltage charger may be able to charge a battery slightly more. For example in a lead-acid battery a lot of voltage can reverse crystalization in the battery (also known as "memory"). Now we are treating electricity as a "compressable" substance in this analogy, and this compressability of the electricity in this analogy in real terms is measuring if the battery can have more electrons pushed into it with a higher voltage (Well actually removed from it).

    IN CONCLUSION: If you're charging overnight you don't CARE about amperage, you ONLY care about the voltage of your charger. I would expect a higher voltage charger to help slightly.
    John I likes this.
  12. baddress

    baddress Well-Known Member

    To be fair to the matter you must also mention that while applying greater voltage to the battery during the charge cycle will increase it's capacity by perhaps 10%, it may also reduce the lifetime of the battery (which only has a 2-3 year lifespan to begin with). So you may get more battery charge life in the short run but need a new battery sooner than usual. It depends the quality of the cells Samsung is using. Upping the charge current will get the battery to stage 2 (full voltage) faster but the topping charge will take longer. This could actually be slightly detrimental since you want to avoid maintaining the battery on a charger at full voltage. The 700ma charger has a more smooth charge curve if you will. So not to start an argument but really as long as the voltage is within range, amperage does matter much more especially with overnight charging. You actually want to charge the battery as slow as possible overnight so that you don't hit the voltage limit prematurely. I admit I break this rule with my 950ma car charger but sometimes you need a fast boost of 20-30% and I don't leave it on the car charger for very long. Also you can tell by the battery icon on your phone if you are in stage 1 or stage 2, stage 1 is an animated filling-up charging icon and stage 2 is a static charging icon. Lithium Ion has a mess of circuitry in the battery itself to regulate charging cycles, etc, so it's not inconceivable that some of the battery run is defective with regard to charge/discharge performance. In fact a full discharge cycle doesn't actually improve the battery any, but it does calibrate the battery's internal circuits so that they more accurately report to the phone what the battery status is.
  13. MarkMillerNJ

    MarkMillerNJ Lurker

    I noticed that it goes from 1/2 to red in a very short time. Anyone else notice this?
  14. baddress

    baddress Well-Known Member

    The discharge curve of Lithium Ion is not linear. There is a low voltage cutoff point so you never actually get more than 97% out of the battery. Additionally, Samsung has chose n some odd percentages for the display meter, here are the trigger points- 100%, 80%, 60%, 40%, 25%, 10%, and 5%. Red kicks in at 10%, orange at 25%, and "half" on the icon is really only 40%. Also it seems they may have left the 60% marker out or it is really close to be almost indistinguishable from 80%. So yes they way it is displayed you may think your phone is 100%, 75%, 50%, 25%, but really due to the closeness of the ranges you are most likely noticing it at 100%, 80%, 40%, 25%.
    MarkMillerNJ likes this.
  15. Ductapemaster

    Ductapemaster Newbie

    OK, so speaking as an electrical engineer, a higher voltage battery charger will not effect the charge rate, but a higher current one will. This is assuming of course that the voltage output of the charger is adequate for the charger in the phone to work, but we don't have to worry about that here.

    The lithium battery inside the phone uses a method of charging called "constant voltage" meaning that the voltage being input to the battery is constant (usually the voltage of the battery, in this case 4.2V for a charged cell), while the current is varied to meet the need of the battery. The speed of the charge is determined by how much current can be input to the battery, which in this case means how much the charger can output. At maximum, the current entering a lithium cell during charging should not exceed its rated capacity, meaning for our battery, the maximum charge current is 1.5A. Theoretically, a 1.5A (number derived from the 1500mAh rating on the battery) charger would provide the fastest charge rate for the Captivate.

    The main limiting factors on charge rate are:

    1. Charging circuitry inside the phone: the chip used to control the battery charge may have a maximum current it supports. If it were say 1A, you would notice a difference in charge time if you had a charger that outputs 1A, but any higher and you wouldn't see a difference.

    2. Micro USB connector: In our case, this doesn't apply, as the current rating on the power rails of the connector are rated at 1.8 amps, but it could affect higher capacity phones.

    3. The voltage regulator: these is a chip (most likely a few) inside the phone that takes the voltage from the battery/charge port, and regulates it for the rest of the phone. This could mean lowering or raising the voltage to meet the needs of the circuitry. The regulator(s) may have a current rating on them that is less than 1.5A, which would limit the charge rate.

    So, long story short, a higher current charger will charge your phone faster, but only to a point. Unfortunately, without knowing what charger chip is used in the phone and how/if it is controlled by the software, we won't know the limit. However, a max value we do know is 1.5A.

    If you guys find a charger that can output 1.5A, try it out and see if it charges faster than other chargers. That is the only way to know for sure, as we don't know how the charging/regulating circuity is designed.

    Also, as a warning, don't use chargers that aren't meant for charging USB devices. A higher voltage charger could damage the phone.

    *Disclaimer: There is no way to determine the maximum supported current rate for the phone, so I take no responsibility for you guys trying out other chargers if they damage your phone. I am simply spreading some general knowledge about battery tech.
  16. heathric

    heathric Lurker

    Hey guys. Some of your electrical theory is completely backwards.

    Voltage is like water flow... the speed at which water flows out of a pipe. too much flow will flood your basement because the drain can't handle it all.
    Current is like water pressure... the force of which water flows through the pipe. too much pressure might bust a pipe..

    but these conditions have little to do with our phones.

    The charging circuit is rated at USB voltage which is ALWAYS 5v. Never ever ever under any circumstances apply higher voltage into your phone. You will fry it.

    Let's think of it a different way. Take a little single cell AA flashlight bulb. If you hook up 8 AA(1.5V) batteries parallel, you still get 1.5V, but you get 8 times the current(amps) so hook that up to your flashlight and it will last about 8 times longer than the single battery because you have the same voltage, but more current.

    If you take the same 8 AA 1.5V batteries and hook them up in series, you will have the same current(amps) as a single AA, but you will have 12V. Hook that up to your flashlight, and it will blow the bulb immediately.

    We are not interested in volts here always use a 5V supply charger. We want more current.

    About USB, if a device draws less than 100mA (.1A) then the computer doesn't detect the device and won't enumerate. Since our phones draw more than that when mounted (enumerated by the USB bus) the USB cable from the computer can supply up to 500mA(.5A) with USB2.0 or up to 900mA(.9A) with USB3.0

    Ultimately, the USB charging method usually can't compare to a house mains or car charger. Typically these are from .7A(stock samsung charger) or up to nearly 2A for an aftermarket charger.

    You can use a higher current charger for your phone and it may charge faster, better, and fuller.... but NEVER get a charger that uses more voltage, as it will melt the voltage regulator in your phones charging circuit. Most charging circuits have the "idiot provision" built in to protect itself from idiots using slightly higher voltage chargers... but we're not idiots, and we know better than to use higher voltage chargers.

    Grab a 1.5A (or higher) USB charger from microcenter, bestbuy, radioshack, or wherever but make sure it regulates voltage at 5V internally. You may find a charger that has even more then 2A current... should still work fine because current is only used as needed. If 2A is available from the charger but your phone only draws 1.8A...max... this is perfect.. your charger won't be working at it's full potential, yet your phone will have available all the current it needs to charge while you're surfing the internet with the screen on full blast and everything else running....

    the point remains... never ever ever use a charger with more than 5V.
  17. baddress

    baddress Well-Known Member

    The maximum charge current the phone will draw is 1.0a. Using a charger that is rated for higher than 1.0a will give you no benefit as the phone will never draw more than 1.0a.

    Additionally please reference what I mentioned about charging Lithium Ion, higher charge current (in this case a max of 1.0a) will charge the phone faster, but not significantly faster, and is not great for the battery in general since the battery hits max voltage faster and stays there longer.
  18. myrv

    myrv Member

    I use the same charger that I had used for my iPhone oddly enough (well the same power brick). It is the extended length cable and power brick that is sold for the iPad, which I like because of the extra cord length. With this and the Samsung USB cable I get a 100% charge that lasts for at least an hour of standby time. I still get a rapid discharge of battery if I do much in the way of apps. I am going to have to run some tests with an app killer and see if I can find exactly what apps are causing the battery drain.
  19. taylormah

    taylormah Well-Known Member

    I found this charger on amazon and it has usb port for both 2.1A and 1A. If I were to lets say connect the phone in 2.1A port instead of 1A port, will it charge any faster (that is if phone can draw more than 1amp)?? Also, I heard 2.1A port is usually used for iPad charging. Will it damage other USB devices like phone in any way if I were to use 2.1A port for charging??
  20. Ductapemaster

    Ductapemaster Newbie

    Where do you get the 1A figure? Is it in the stat sheet somewhere?

    This is somewhat inaccurate, sorry. The recommended charge rate for lithium batteries (that is, without damaging the battery) is charging at 1C or 1 times the capacity of the battery. In this case, that mean 1.5A. This is assuming that the charge circuity doesn't have a pre-programmed limit below that. Also, the charge circuity is set up in the phone so it doesn't charge too fast anyways, so supplying the phone with more current than it needs to charge properly won't hurt it a bit.

    Charging at less than 1C may prolong the life of the battery a bit, but the longevity increase would be so small I doubt a person would notice it.

    You will be fine if you use the 2.1A port. The phone will only take the amount of current it needs from the port. If it needs 1A it'll draw 1A. Its not like the charger will force extra current into the device, as would be the case if you used a higher -voltage- charger.
  21. baddress

    baddress Well-Known Member

    Yes. It is probably printed on the phone somewhere too, I haven't looked real hard for it besides the spec sheet.
  22. malibu_rapper

    malibu_rapper Member

    I use the charger that came with my Motorola Q. Works a lot better than the OEM charger!

Samsung Captivate Forum

The Samsung Captivate release date was July 2010. Features and Specs include a 4.0" inch screen, 5MP camera, 512GB RAM, Hummingbird processor, and 1500mAh battery.

July 2010
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