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[Q] Is any kind of fast charging possible?

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mattb22
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Plug [Q] Is any kind of fast charging possible?

Team,

First off, I want to say thank you for creating an amazing resource for these phones. I currently have a Galaxy S4 Active MF3. I bought the phone with the intent of using it in conjunction with my car stereo, which is a Pioneer 8500 BHS. I've paired this up with a Samsung MHL 2.0 adapter and ARLiberator. On top of this, I have installed a OBD-II bluetooth module in the car that also communicates with the phone. The end result is that the phone delivers full touch screen control of all apps on the phone, full bluetooth hands free calling, voice control, GPS (Tom Tom), Pandora, and most importantly, gives me a second dashboard where I can customize any gauge that the car did not offer stock, such as boost gauge, wideband air/fuel ratio, exhaust gas temperature, and a few other things. I'm using the full version of Torque to do this. It is amazingly useful, with one exception. The Samsung MHL adapter never lets the phone charge at more than 300 milliamps. The USB connection straight from the stereo charges at 900, and a 2.1 AMP charger with the Samsung cable will charge at 1900. However, regardless of the combination I use, the MHL always cuts this down to 300. This causes the phone to lose about 15-20% of it's charge every hour. For short trips, this is OK, but for longer trips, I can no longer use GPS, which is a big problem, as that's the whole reason I got the phone. Other users of the standard Galaxy S4 and this combination have been able to get around this issue by installing a ROM with Fast Charge enabled, which gives them 800 milliamps. This is just enough to let the phone be used and slowly charged at the same time.
I understand that currently we're limited to stock kernels with modifications layered on top (GoldenEye, ETC...), and that the Fast Charge code requires a kernel recompile in order to function. Is this correct? Do I have any other options? I've considered wiring in a wireless charger just to get the phone to charge on long trips, but I'm concerned that wireless charging in addition to the USB input and charge may cause the battery to overheat or reduce it's life.
Any ideas?

Thanks in advance,
Matt
 
shaDNfro
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(Last edited by shaDNfro; 10th March 2014 at 09:19 AM.) Reason: long useless quotation, inprecise input, spelling
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as far as I know, there is a possibility of welding a 100 Ohm (or just short circuit (more risky, but I've read that some guys using a standard usb cable with simple bypassed Data-wires in combination with the S4A)) between the D+ and D+ wires of the USB-Cable (should be the green and white wire within the cable). Regarding http://www.usb.org/developers/devclass_docs a resistance below 200 ohm is the sign for a dedicated charging cable/device.
I've seen a manual of an sgs user, having full loading speed in his car, using a modified cable. Unfortunately his manual is in German, u can find it here. All credits belong to him.

by the way, i am pretty sure u will find an similar manual within this xda-board using the right search patterns, cause It does not seem to be device related.
 
mattb22
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shaDNfro,

Thank you very much for your reply, but unfortunately the 'cable mod' will not work in this instance. The reason that it won't work is that the stereo needs the Data + and Data - for Audio and synchronization data being sent back to the headunit for broadcast, and the MHL blocks the D+ and D- resistance from reaching the phone. To verify this, I took a stock Samsung cable with a voltage inverter in the car, and wired the whole system up into the MHL adapater. The system still charges at 300 ma, despite the fact that I can plug the same cable going into the MHL directly into the phone and get 1900 ma. If I use a 'modded' cable without the inverter, then the MHL still charges at 300 ma, but AppRadio will not function, as it gets no signal from the data ports on the USB. To add insult to injury, the MHL input is a 12 pin interface, and shunting D+ and D- cables on the MHL output is dangerous, as the system is doing more with the 12 pins than a standard 4 pin USB. I really don't want to fry a 400+ dollar phone.

What we really need here is one of two things:
1. The ability to upload a recompiled kernel into the system (I know that we have a bounty on this and it's not going anywhere)
2. The ability to modify the input amperage without a recompiled kernel

I'm not sure if either of the above two things can be done. I'm either going to have to live with this or get a new phone.

If ANYONE has any other ideas, please let me know!

Matt
 
Vaiski
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Is it possible to mod usb cable to take the power directly from car charger?
Connect usb chargin wires to car charger from phones end of usb??



Sent from my GT-I9295 using poor english.
 
mattb22
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Quote:
Originally Posted by Vaiski View Post
Is it possible to mod usb cable to take the power directly from car charger?
Connect usb chargin wires to car charger from phones end of usb??



Sent from my GT-I9295 using poor english.
Vaiski,

That's not a bad idea! From some more of my recent research, it appears that I now have three options I can look into:

1. Vaiski's idea of adding a 2.1 AMP second USB line to the + and - phone input while cutting the current MHL + and - cable output. This would essentially allow the MHL to get its power from the stereo's USB input, and the phone to get its power from an external, high amperage USB line and still allow me to keep the data flowing between the phone, MHL adapter, and stereo. I've got a second 'generic' MHL adapter that I wouldn't mind cutting up to spare my $50.00 Samsung MHL adapter if this doesn't work. This wouldn't allow the system to get the full 1900 ma, but it should get me upwards of 300 ma, which is where I am now.

2. I can add a wireless charger into the mix. From what I've read, if you charge with USB and wireless charging at the same time, the wireless charging would take priority. This would give me the same results as option #1.

3. I can try using the samsung S4 Multimedia dock. It appears that the dock doesn't have the same voltage output limitations as the MHL adapter. It does cost $100.00, though, and it's rather bulky.

These are all really great ideas, but what really bothers me about all this is that it shouldn't be necessary. If Samsung/AT&T hadn't installed a bootloader kernel checksum, none of this would matter. I could simply put a custom kernel in and call it a day with my current hardware. Hopefully someone will crack the bootloader soon. That would really be the best option instead of being locked into 4.2.2.

Thanks again!
Matt
 
Greeves66
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Smile s4 active charging

Quote:
Originally Posted by mattb22 View Post
Vaiski,


Thanks again!
Matt
I don't know whether or not you found a solution to your problem yet. I discovered same problem using stock charging cable and having Bluetooth, Wi-Fi amd GPS turned on, playing music through usb to a pioneer stereo.... no Bluetooth on stereo, but was using a BT hands-free device. Anyway, same problem as you, charger wouldn't keep up. Tried turning off Wi-Fi... had mobile hotspot turned on for wife's tablet, helped some but still drained faster than charged. A couple months ago, I couldn't find the factory charging/data cable and phone needed charging, so I tried a cable from one of those battery powered phone chargers, thing is only about a foot long, but phone said "charging" it went from about 30% to full in less than an hour, this phone has never charged that fast. I've experimented with it a bit, and it won't work as a data cable but it will keep up with everything turned on. I don't know if it's the length of the cable, or if the pins on the cable are different, in any case, try different cables, if you only need charge while your driving then the lack of data won't be a problem, though I liked being able to charge and listen to music at the same time, I'd rather know that my phone won't be dead when I get to the other end of a long road trip.... besides I figured out that a flash drive plugged into stereo plays music better.

Hope this helps
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