5v 2A charger for high current usb

[jms1989]

Using the pic as a guideline, I'm trying to make a 2 amp per device charger only I'm not entirely sure if it even works because the current stays the same with or without the resistors. I've tried it with my little lg500g and kindle fire without the hd stuff and my two sisters' ipod touch. now, the kindle calls for 5v @ 2.1A but it never draws more than 450ma, regardless of resistor layout. I put 2.8v on the D+ and 2v on the D- pins but no improvement. I would think the kindle would just start pulling more but never did. I don't understand what I did wrong. I'm wanting to power 4 devices with 8 amps of total current. Another issue is, if all devices are plugged in when power is applied, some will start charging and some will just sit there but if you plug them in, one at a time with power applied, they start charging. Do I need seperate dividers on each data pins? the supply is capable of at least 15amps at 5v. Also, if I use a regular 1 or 2 amp wall wart, I notice a .3 v drop on the load. that can't be good. my 15amp supply gives them 5.02v under load so idk.

Any tips?

 

[Kripton2035]

if I remember the trick with voltages on D+ and D- only works for iphones (and may be ipods but not sure)

 

[jms1989]

yeah, the ipod touch current didn't change even though they are provided with 1amp chargers. Kinda sucks, I'd like to make sure it works before installing it into my truck. Another thing I noticed, if the devices are plugged in before power is applied, some will try to mount their filesystems, like my phone will prompt to connect as mass storage but there's no host. I guess I could just make it with two dividers on the data pins and hope it works right when needed. I just thought it might had worked on other devices. I was hoping it'd work on the kindle. I can't seem to find any solutions for it other than people talking about how crappy the charging system in it is. It's slow to charge and even slower when plugged into a computer.

 

[tpetar]

What motherboard you have?

You need to install motherboard manufacturer software for this, this is one option for charging over PC.


Check Gigabyte and ASRock :

https://www.gigabyte.com/MicroSite/185/on-off-charge.htm
https://www.gigabyte.com/support-downloads/Utility.aspx?cg=2

https://www.asrock.com/feature/appcharger/index.asp



Best regards,
Peter

 

[Kripton2035]

what ipod touch generation do you have ?
the voltage on d+ and d- depends on that.
https://learn.adafruit.com/minty-boost/compat-v3

also the mysteries of apple chargers :
https://learn.adafruit.com/minty-boost/icharging