Will a 2 amp car charger fry the Evo?Accessories

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  1. cabbie

    cabbie Well-Known Member

    I got a 2 amp car charger for my nook color and want to know if its safe to use for the Evo. I know the Evo typically charges at either 1 amp (out of wall) or 0.5 amp (out of computer), but not sure if this was risky.

  2. cabbie

    cabbie Well-Known Member

    actually i think its likely the cause the evo will throttle the amp down to 1, right?
  3. Palmetto Fellow

    Palmetto Fellow Well-Known Member

    Yes, I think if Voltage is the same, the EVO will draw whatever it needs.

    I have a Rocketfish Premium Car charger that is fused at 2 amps. The EVO takes what it needs.

    However, maybe wait on someone with direct electronics knowledge to chime in before you do anything...
  4. Rigmaster

    Rigmaster Well-Known Member

    You should be fine, but unplug once charged. Extra power just means heat risk will go up.
  5. joe123

    joe123 Well-Known Member

    Can we use a 2 amp USB car charger on the EVO?

    When the EVO is on and pluged into the car charger charging at 1 amp (1000 mHa), and the EVO is taking up ~680 mHa being on with say Navigation, the actual juice going INTO the EVO is 1000 minus 680 or 320 mHa max charging.

    So a 2 amp car charger would be great when you need to BOTH charge the EVO at it's max 1000 mHa rating AND use it for energy hungry applications (like navigation).

    Or can the EVO not be able to do this?
  6. eluno

    eluno Well-Known Member

    even if this does work. just think about the amount of heat this will produce. not a good idea imho. but what the hell do i know:rolleyes:
  7. Rigmaster

    Rigmaster Well-Known Member

    Yes, you can use it. But that's why I advised that you unplug as soon as the charge is done. Once the Evo's charged, the phone then has to convert ALL the 2 Amp energy into heat. I bet if you do this, you'll notice the phone heats up pretty quickly. Not sure if it's enough to "fry", but it's enough to cause damage.

    I don't think it's correct to assume your equation in how the power is being used. More likely the Evo's been set not to handle any more than 1000mah at any time.

    Charging with the extra 1 amp just leaves more electrical energy to be dissipated. That conversion is probably going to come via heat. It may not do immediate or short-term damage if only done once in a while. However, doing it regularly could cause problems. Since there's no transformer between your Evo and the power source other than the charging cable, your Evo will become the heat sink - not good.

    That's why wall and portable chargers are basically electrical transformers designed to reduce the power coming out down to the preferred level (1000mah) so the phone doesn't have to.

    I have a 2A charger in my car, but it's actually a dual, 1 amp charger with two 1 amp ports so I can charge both my wife's and my Evo at the same time. It's possible to have gotten a 2 amp charger with one outlet and simply used a dual-usb cord, but I don't think that makes sense when the correct option was available.
  8. Palmetto Fellow

    Palmetto Fellow Well-Known Member

    The EVO stops charing when it's full. This is part of its design. I don't think any heat will build up.

    The ROCKETFISH charger I have says 2A on it. Everything works fine.
  9. joe123

    joe123 Well-Known Member

    Are you able to verify the following with the Current Amp Widget:

    With an almost drained battery: Charge the EVO with your ROCKETFISH charger AND run Google Navigation with 4G, Bluetooth, WiFi all set ON and see what the charger is charging the EVO at?

    My EVO consumes around ~680 mAh with all of those features turned on including Navigation.

    Your ROCKETFISH charger should be able to charge close to the 900-1000 mHa (while consuming ~680 mHa) with it's 2 AMP rating.
  10. Rigmaster

    Rigmaster Well-Known Member

    Ok, but there's still current flowing that will be dissipated as heat.
  11. Palmetto Fellow

    Palmetto Fellow Well-Known Member

    Are you 100% sure that the EVO will draw more than 1 amp? I could forsee a situation where the HTC engineers have put a limit to the current draw of the EVO. Even if I can supply 2 amps, the EVO may never draw more than 1 amp. Or 1.25 amps...or whatever random number they decided to cap it at. IMHO, the main reason for the 2 amp charger is so that when you use the extra USB port on it, you can get 1 amp to two different devices...rather than 2 amps to a single device. A quick question about your settings...do you simply have BT on, or do you actually stream music via A2DP to BT?

    I was unable to let my battery drop all the way down, but I did a test at about 50% on my way in to work today. I had 4G on, GPS on with Google Nav directions to the office, streaming Pandora, and sending the audio via BT A2DP to a BT FM Transmitter and I left the screen on. I forgot to leave WiFi on, sorry about that. The results are below. I deleted all redundant information from the log. If there were 10 entries for 408mA at 51%, I used the first entry, and deleted the other 9. Some of the really low dips are likely when Pandora started downloading the next song, but I can't confirm this.

    2011/01/14 07:59:42,-618mA,50%
    2011/01/14 07:59:52,0mA,50% (plugged it in right here)
    2011/01/14 08:00:02,632mA,50%
    2011/01/14 08:00:28,580mA,50%
    2011/01/14 08:00:58,384mA,50%
    2011/01/14 08:01:29,590mA,51%
    2011/01/14 08:02:02,594mA,51%
    2011/01/14 08:02:32,408mA,51%
    2011/01/14 08:02:58,398mA,51%
    2011/01/14 08:03:28,542mA,52%
    2011/01/14 08:03:58,392mA,52%
    2011/01/14 08:04:29,290mA,52%
    2011/01/14 08:04:59,596mA,53%
    2011/01/14 08:05:30,536mA,53%
    2011/01/14 08:06:00,418mA,53%
    2011/01/14 08:06:31,412mA,53%
    2011/01/14 08:07:01,368mA,53%
    2011/01/14 08:07:32,370mA,54%
    2011/01/14 08:08:02,432mA,54%
    2011/01/14 08:08:32,566mA,54%
    2011/01/14 08:08:58,442mA,54%
    2011/01/14 08:09:29,302mA,55%
    2011/01/14 08:10:02,374mA,55%
    2011/01/14 08:10:32,358mA,55%
    2011/01/14 08:10:58,432mA,55%
    2011/01/14 08:11:28,582mA,56%
    2011/01/14 08:11:59,426mA,56%
    2011/01/14 08:12:29,376mA,56%
    2011/01/14 08:13:00,366mA,56%
    2011/01/14 08:13:30,404mA,56%
    2011/01/14 08:14:00,384mA,57%
    2011/01/14 08:14:31,480mA,57%
    2011/01/14 08:15:01,326mA,57%
    2011/01/14 08:15:32,562mA,57%
    joe123 likes this.
  12. Rigmaster

    Rigmaster Well-Known Member

    Evo limits power drawn. Charger delivers more than needed. No transformer in between. Any extra power will be converted to heat. Good news is charger probably doesn't have regulator putting out only 2 amps and instead has one that puts out up to 2 amps.
  13. Palmetto Fellow

    Palmetto Fellow Well-Known Member

    I must admint, I'm no electrician...

    Why would there be extra power? The EVO will take what it wants, and leave the rest. Why is it that the charger must send the extra power somewhere (heat)?

    Imagine plugging a 3 amp device into a standard 15 amp NEMA home outlet. What happens to the extra 12 amps? Is a tremendous amount of heat generated?
  14. joe123

    joe123 Well-Known Member

    Thanks Palmetto, that is very helpful.

    So here is the critical question. When we see an entry like:

    • 632mA,50%

    Does that mean 632mA going to charging the Battery (I think so)? If yes, then the EVO is indeed taking in more than 1Amp. I say this because the EVO with all of the things turned-on you have above will draw more than 700mA.

    So if the EVO is consuming say 700mA and the log shows a possitve 632mA, then total energy going into the EVO is 1,332mA of which 632 went to the battery.

    Any electrical folks here that knows the answer? :D
  15. Palmetto Fellow

    Palmetto Fellow Well-Known Member

    Those entries are definitely the current going into the battery. That's what current widget looks at. However, pandora is not constantly downloading content. To say that the evo constantly drawing 700mA may be incorrect.

    I can run another log while not charging to see the total draw while running all those services.

    Notice how out drops to 300mA sometimes? I suspect that's when pandora is downloading content.

    I would like believe that out can draw more than 1amp though.
  16. Rigmaster

    Rigmaster Well-Known Member

    I'm not an electrician, but I build and tinker with electrical components as a hobby. As a general rule, amps are usually not a problem as they're really controlled electrical flow. The control comes from the device's current regulators (transformer or software requesting amount of power). Those requests are made from the Voltage of the powering device - your iPad charger - which also makes that same request by dipping into the outlet for power. The iPad charger has a transformer to smooth out and dissipate the extra voltage that comes from the wall (volts are spikes rather than continuous flows of power).

    As long as the iPad charger Voltage does not greatly exceed the voltage of the Evo, you should be fine. The amps really aren't a factor.

    The reason US-intended electronics fry on international outlets is the volts. The power spikes are too high for the transformer/software regulators to handle.
  17. Palmetto Fellow

    Palmetto Fellow Well-Known Member

    It's not an iPad charger. It's for all micro-USB devices. It is a 5V device, and internally fused at 2 amps. Since the amps aren't a factor, I don't see where the excess heat is going to come from. What did you mean before about the excess heat?
  18. Rigmaster

    Rigmaster Well-Known Member

    The 5 volt is key. There will be heat but not likely measurable or damaging.
  19. joe123

    joe123 Well-Known Member

    That would be helpful to get a base line.

    If you can get a log for say 10 minutes not plugged in and then simply plug in the charger, the difference (average) will show if the EVO is indeed consuming more than 1 Amp when the charger is plugged in.

    If yes, then that is great which will show the charger is putting out enough juice to run all those applications AND also charge the battery close to the 1 Amp rating :D
  20. dajeepman

    dajeepman Active Member

    dont know about yall. but my 500ma plug gets really warm when charging my EVO so does the OEM wall charger..
  21. mcl1981

    mcl1981 Well-Known Member

    Amps are drawn, not pushed or sent. The phone will not draw enough current to overheat because no idiot would design the power supply to do that. If the power supply in the phone is limited to 1amp, then that is all it will draw from the charger. If it allows more than an amp, then congratulations you will be able to charge the battery faster while using a lot of power hungry apps too.
    Herf N Turf likes this.
  22. scubabear1

    scubabear1 Member

    Ive been using a 2A charger since day 1 with no problems
  23. cephraim

    cephraim Well-Known Member

  24. Herf N Turf

    Herf N Turf Active Member

    Any excess voltage has to be dissipated somewhere, either in the charger (resistors), the cable (inherent resistance), or the device (capacitance). All excess is turned into heat and must sink. Think of this as running your finger across a piece of wood. As long as the friction you're creating doesn't exceed the ability of the medium to dissipate the energy created, all is comfortable. Do it too fast and you're gonna need a bandaid.

    It's always best practice to unplug any device as soon as you see a "full charge" indicator.
  25. mcl1981

    mcl1981 Well-Known Member

    What you have described is completely wrong. That is not how electricity, current, or voltage works

    As I already said before, amps are drawn by the device as it is needed. You could put a 200,000amp charger on it. It will still only use what the phone's charge controller calls for, which will be anywhere from zero to 1000ma.

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