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Old January 11th, 2011, 03:13 PM   #1 (permalink)
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Default Will a 2 amp car charger fry the Evo?

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.

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Old January 11th, 2011, 03:22 PM   #2 (permalink)
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actually i think its likely the cause the evo will throttle the amp down to 1, right?
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Old January 11th, 2011, 04:19 PM   #3 (permalink)
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actually i think its likely the cause the evo will throttle the amp down to 1, right?
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...
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Old January 11th, 2011, 09:59 PM   #4 (permalink)
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You should be fine, but unplug once charged. Extra power just means heat risk will go up.
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Old January 12th, 2011, 10:47 PM   #5 (permalink)
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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?
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Old January 13th, 2011, 02:09 AM   #6 (permalink)
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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?
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
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Old January 13th, 2011, 09:13 AM   #7 (permalink)
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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?
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.
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Old January 13th, 2011, 10:21 AM   #8 (permalink)
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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.
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Old January 13th, 2011, 01:47 PM   #9 (permalink)
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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.
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.
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Old January 13th, 2011, 09:09 PM   #10 (permalink)
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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.
Ok, but there's still current flowing that will be dissipated as heat.
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Old January 14th, 2011, 07:53 AM   #11 (permalink)
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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.

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%
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Old January 14th, 2011, 08:34 AM   #12 (permalink)
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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%
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.
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Old January 14th, 2011, 09:12 AM   #13 (permalink)
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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.
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?
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Old January 14th, 2011, 11:10 AM   #14 (permalink)
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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...
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?
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Old January 14th, 2011, 12:34 PM   #15 (permalink)
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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?
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.
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Old January 14th, 2011, 03:17 PM   #16 (permalink)
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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?
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.
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Old January 14th, 2011, 07:12 PM   #17 (permalink)
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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.
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?
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Old January 14th, 2011, 07:37 PM   #18 (permalink)
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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?
The 5 volt is key. There will be heat but not likely measurable or damaging.
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Old January 15th, 2011, 03:43 PM   #19 (permalink)
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I can run another log while not charging to see the total draw while running all those services.
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
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Old January 22nd, 2011, 11:57 PM   #20 (permalink)
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dont know about yall. but my 500ma plug gets really warm when charging my EVO so does the OEM wall charger..
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Old January 23rd, 2011, 07:26 PM   #21 (permalink)
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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.
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Old May 30th, 2011, 08:10 PM   #22 (permalink)
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Ive been using a 2A charger since day 1 with no problems
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Old July 6th, 2011, 08:38 AM   #23 (permalink)
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Just bought this 2A charger from buy.com.

Buy.com - High Powered USB 2.1amp Car Charger for iPad 1 & 2 and Mobile devices
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Old July 14th, 2011, 07:31 PM   #24 (permalink)
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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.
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Old July 15th, 2011, 01:55 PM   #25 (permalink)
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Originally Posted by Herf N Turf View Post
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.
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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Old July 5th, 2012, 06:22 AM   #26 (permalink)
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Hey guys,

I have a small company that makes an app for farmers that uses GPS to detect their time on the fields. We have some farmers running on Viewpad 7 tablets. Their normal household charger for the device has output of 5v and 2 amps. So we found a car charger for their tractor which outputs 5v and 2,1 amps. But after 10-12 hours of running the app (with full screen contrast and active GPS) the battery will run dry.. completely dry.
Do you know why this is? Could it be the USB cable that cannot deliver 2 amps from car charger to device? Or is device using more than 2 amps for screen and GPS?

Help!
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Old July 5th, 2012, 09:32 AM   #27 (permalink)
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How long does it take to deplete from full when not plugged in? If it depletes slower when plugged in, the issue is just that the device is using power faster than it's being delivered via the usb cable.

Some auto usb cables simply don't deliver the power they advertise.

Figure out if (using the unplugged/plugged test above) and then decide whether you need to try a cable from a different manufacturer.

I use a Scosche charger that does 5v, 2.1a and charges my iPad2 in the car with no problem. I had a similar product from another brand that was supposed to work the same but didn't.
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Old October 27th, 2012, 03:08 PM   #28 (permalink)
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if you download the battery widget you can see voltage and temperature.
On my 2 amp car chargers I get readings of around 4300mV and a temperature of 86 while not using the phone.
I have a 7.6 volt 1 amp wall plug charger and get a reading very similar.
So the phone only uses the volts and amps it is set at.
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