HDMI mirroring

**byrds8** · 01-20-2012, 09:49 PM

When any of you watch a movie using your phone and putting it up on the big screen, does your battery still drain or does it still charge like normal? I know I just watched a movie and it went from 60ish down to 39%. Is this normal?

**jdbower** · 01-21-2012, 04:36 AM

My charger only draws <500mA when connected to the MHL adapter, it draws closer to 1000mA when connected to the phone directly. At 500mA it's quite likely your phone will discharge faster than it can charge; you can try standard battery saving techniques like switching to the lowest backlight setting, shutting off unnecessary radios, etc. It's a pain and I hope someone can find an MHL adapter that can pull the full 1A to keep the phone charged.

**justintiburon#ac** · 01-21-2012, 08:09 AM

How do you do this? I don't see an HDMI slot like my x2 had. Am I an *****?

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**jdbower** · 01-21-2012, 08:20 AM

You need something called an MHL cable. It plugs into the micro USB port and has a (usually) full-sized HDMI port on the other end. There's also typically a micro USB port to provide power to the adapter and phone while it's in use.

**mechapathy** · 01-21-2012, 11:52 AM

I have the Samsung MHL adapter which requires a secondary power source and the battery drains about 5-10% per hour, depending on the intensity of use.

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**byrds8** · 01-21-2012, 11:58 AM

Streamed a HD movie for 106min

**justintiburon#ac** · 01-21-2012, 02:26 PM

Originally Posted by jdbower

You need something called an MHL cable. It plugs into the micro USB port and has a (usually) full-sized HDMI port on the other end. There's also typically a micro USB port to provide power to the adapter and phone while it's in use.

Thanks man hope they arnt expensive

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**jdbower** · 01-21-2012, 02:45 PM

Originally Posted by JustinTiburon

Thanks man hope they arnt expensive

Easily found for <$20 shipped on Amazon, you can also try Monoprice.

**ztmike** · 01-21-2012, 02:54 PM

Will this one work with the Galaxy Nexus?

I'm sure it would since it should just be a standard mirco usb fitting..but just want to make sure before I spend the money.

Edit: Okay just read the review comments and it looks like it is only capable of 500mA charging and not 1000mA charging according to a Monoprice administrator. Is there any out there that work with the GN and is capable of 1000mA charging?

**TabGuy** · 01-21-2012, 03:12 PM

Originally Posted by JustinTiburon

Thanks man hope they arnt expensive

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It's not. $10.20 at Monoprice.com.

**jdbower** · 01-21-2012, 03:27 PM

Originally Posted by ztmike

Edit: Okay just read the review comments and it looks like it is only capable of 500mA charging and not 1000mA charging according to a Monoprice administrator. Is there any out there that work with the GN and is capable of 1000mA charging?

It'll work just fine, but I haven't found any that allow for 1000mA charging. Officially the standard says 500mA, but so does the USB spec so I don't know if one even exists.

**byrds8** · 01-21-2012, 05:08 PM

Ya know I just thought about it but it might not be able to do a full 1A charge because its inputting and outputting at the same time. Maybe when its on the wall charger it uses all lines in for charge but when its on USB or the MHL adapter it uses two for outputting. Dont really know since I havent seen the schematics of it but its a logical guess.

**jdbower** · 01-21-2012, 05:59 PM

Originally Posted by byrds8

Ya know I just thought about it but it might not be able to do a full 1A charge because its inputting and outputting at the same time. Maybe when its on the wall charger it uses all lines in for charge but when its on USB or the MHL adapter it uses two for outputting. Dont really know since I havent seen the schematics of it but its a logical guess.

I actually measured at the source, I happen to have an old HP (pre-Agilent) laying around (you can set the voltage and it will display the current). The <500mA was both what was being sent to the phone and what was being used by the adapter (the latter is minimal, it's just a chip that needs power).

**byrds8** · 01-21-2012, 06:05 PM

You can measure anywhere along the line you want to, if the device drawing the power is only pulling 500ma it will measure the same all the way. The wall outlet is capable of much more but if something doesnt pull it out it doesnt make a difference.

**jdbower** · 01-21-2012, 06:48 PM

Originally Posted by byrds8

You can measure anywhere along the line you want to, if the device drawing the power is only pulling 500ma it will measure the same all the way. The wall outlet is capable of much more but if something doesnt pull it out it doesnt make a difference.

Unless you're measuring between the MHL and the phone (or at the phone itself). This would remove any power drawn by the MHL chip itself, of course.

**byrds8** · 01-21-2012, 07:52 PM

Are you saying that the draw was still 1A but the MHL used 500ma and the other 500 was sent to the phone?

**jdbower** · 01-22-2012, 05:51 AM

Originally Posted by byrds8

Are you saying that the draw was still 1A but the MHL used 500ma and the other 500 was sent to the phone?

No, I had a microUSB connector on my 3A power supply. When plugged directly into the phone it draws about 1A max no matter what I do. Screen on, CPU use high, GPS on - nothing matters, if the battery is low it'll pull about 1A.

When plugged into the MHL the max power draw was <500mA. Either the MHL itself is limiting the power to the phone or the MHL chip in the phone is limiting power.

The practical results of my test indicate that upgrading to a better charger will not affect the drain rate using my MHL adapter, but it's possible that other MHL adapters will. Either way, it's not the case that the adapter is consuming the missing 500mA, there is something that is limiting the current.

**byrds8** · 01-22-2012, 06:54 AM

Ok, that makes more sense. Thats why I said I wonder if its down to 500ma because its outputting and inputting at the same time. The phone is powered and outputs the video/sound from the same connection. My theory is that maybe it cant go full power if its doing both so it sets its into USB charging. Only a theory though.

**bunklung** · 02-25-2012, 07:28 AM

Originally Posted by jdbower

It'll work just fine, but I haven't found any that allow for 1000mA charging. Officially the standard says 500mA, but so does the USB spec so I don't know if one even exists.

The standard is 500ma, but that is considered the minimum.

Tim Wong is the president of the MHL consortium.

The problem with the Gnex is that if the connection is detected as USB, it limits the charging to around 500ma. So even IF the MHL adapter or TV supplied MORE that the minimum spec, the Gnex will not pull more that 500ma. On XDA we are working on a mod to enable fast charging on the Gnex.

When I plug in my MHL adapter it reports USB charging.

**bunklung** · 02-25-2012, 07:37 AM

Great info about the amp meter used...

I would say that jives with my assumption. My MHL adapter draws only 500ma. My guess is that it uses 350ma to run and supplies the remaining power to the phone. I need to turn off the screen on the Gnex, and put it in airplane mode and I see about 150ma charge over a ten minute avg.

jdbower, what MHL adater are you using? I am using #8675 from monoprice, which has been discontinued and replaced by #8805. Perhaps #8805 doesn't suffer from shared 500ma.

I would say with certainty, that my MHL adapter does not meet the MHL spec by not providing the minimum 500ma to the phone.

One quick fix would be for manufacturers to have two ports on the MHL adapter, one to charge the device, and one to act as a pass through power.

I wonder if the Samsung MHL adapter suffers the same shared 500ma.

**jdbower** · 02-25-2012, 07:54 AM

I've got this one:
Amazon.com: Menotek Micro USB to HDMI MHL Adapter IMPROVED WITH RCP (Remote Control Protocol) for Samsung Galaxy S2, HTC Evo 3D, HTC Evo 4G Tablet, HTC Sensation 4G, Sprint Epic 4G Touch, Galaxy Nexus: Electronics

However I think this has been updated as well with RCP (I find that pretty exciting, I'd love a touchscreen mounted in my car that I could use to control my phone). I purchased it just before Christmas.

Thanks for the reminder about the XDA thread, I meant to subscribe to it when it popped up and then kept forgetting. I'll try to sneak in a request to have this mod implemented as a "Charge Only" mode - I find PTP/MTP useless since I transfer everything over WiFi and it's a horrible security risk when using public USB charge stations like at airports (you're letting whatever is on the other end have access to your files).

**bunklung** · 02-25-2012, 08:18 AM

If you have a password on your phone, the screen is locked, and you plug in a insecure USB data port, the files will not be shown. You should also have USB debug off to be safe. As soon as you unlock your phone and enter the password the files will be shown on MTP.

Originally Posted by jdbower

I've got this one:
Amazon.com: Menotek Micro USB to HDMI MHL Adapter IMPROVED WITH RCP (Remote Control Protocol) for Samsung Galaxy S2, HTC Evo 3D, HTC Evo 4G Tablet, HTC Sensation 4G, Sprint Epic 4G Touch, Galaxy Nexus: Electronics

However I think this has been updated as well with RCP (I find that pretty exciting, I'd love a touchscreen mounted in my car that I could use to control my phone). I purchased it just before Christmas.

Thanks for the reminder about the XDA thread, I meant to subscribe to it when it popped up and then kept forgetting. I'll try to sneak in a request to have this mod implemented as a "Charge Only" mode - I find PTP/MTP useless since I transfer everything over WiFi and it's a horrible security risk when using public USB charge stations like at airports (you're letting whatever is on the other end have access to your files).

**jdbower** · 02-25-2012, 09:48 AM

Yes, but then I can't use my phone while I'm charging it

Seems like it's a side effect of this mod anyway so I'm happy.

**bjs188** · 02-26-2012, 03:12 PM

Uhhh..... Maybe I'm having issues, but I got that MHL from Amazon and nothing happens. Do I have to enable something? I plugged charger into adapter, adapter into phone, and hdmi into TV. Just noob error, or do I have to tweak something?

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**jdbower** · 02-26-2012, 06:46 PM

There should be nothing else you need to do, the screen switches to landscape mode after a few seconds and your TV should display what's on your phone. Check the connections, if possible swap any cables you can, and probably try another TV. The TV will need to support 720P and you need to make sure you're on the right input.