More power to USB port

[Z86]

Is there any way to boost the power to the builtin USB port? I haven't tested the actual output but it must be pretty low - my phone battery goes down if I'm running a nav app, even though it says its charging.

[ProjectD]

Originally Posted by Z86

Is there any way to boost the power to the builtin USB port? I haven't tested the actual output but it must be pretty low - my phone battery goes down if I'm running a nav app, even though it says its charging.

I am curious also. It charges SO SLOW. I'm no electrician.....but i did check the Fuse box underneath. Perhaps if we increased to a 10 amp or higher?

Manual (i think) says its a 2 or 7.5. I dont know lol

[rmjjensen]

It's the amperage coming from the head unit that controls the USB port. There's no way to "tweak" it. You'd either have to rig up your own LM7805 to the USB power wires or buy one of those cheap cigarette lighter to USB converter and use the bluetooth on your phone instead to stream music.

[xpicer]

Originally Posted by rmjjensen

It's the amperage coming from the head unit that controls the USB port. There's no way to "tweak" it. You'd either have to rig up your own LM7805 to the USB power wires or buy one of those cheap cigarette lighter to USB converter and use the bluetooth on your phone instead to stream music.

Actually i think we can, we can cut the power wire that feeds the usb port, then we grab a diode place it inline facing the usb port. then we grab 12 output from the cigarete lligther or any 12v source , use a resitor to bring down the voltage to 6v or what ever needed. and then tap the power feed wire after the diode, all we will have to watch for is maybe current spikes. ( definitely possible!!! !!!

[wbradley]

Originally Posted by rmjjensen

It's the amperage coming from the head unit that controls the USB port. There's no way to "tweak" it. You'd either have to rig up your own LM7805 to the USB power wires or buy one of those cheap cigarette lighter to USB converter and use the bluetooth on your phone instead to stream music.

A linear voltage regulator? Shouldnt you know the max voltage spec for a trickle charger to your phone first?

[xpicer]

Originally Posted by ProjectD

I am curious also. It charges SO SLOW. I'm no electrician.....but i did check the Fuse box underneath. Perhaps if we increased to a 10 amp or higher?

Manual (i think) says its a 2 or 7.5. I dont know lol

btw the fuses only protect the circuit, changing fuses wont change the amp/ voltage. you can only alter the output source and use a fuse to suit your needs.

[rmjjensen]

Originally Posted by xpicer

Actually i think we can, we can cut the power wire that feeds the usb port, then we grab a diode place it inline facing the usb port. then we grab 12 output from the cigarete lligther or any 12v source , use a resitor to bring down the voltage to 6v or what ever needed. and then tap the power feed wire after the diode, all we will have to watch for is maybe current spikes. ( definitely possible!!! !!!

That's what the LM7805 does - it's a 5V regulator - no need for any voltage divider circuits and it costs something like $1. You'd install the 7805 and take the output leg (5V) and connect it to the power wire in the usb port. Break out the volt meter, find the existing +5V cut it, and then use the out from the 7805 and feed it to the USB port.

Originally Posted by wbradley

A linear voltage regulator? Shouldnt you know the max voltage spec for a trickle charger to your phone first?

It's USB - USB is USB - it's 5V and 250mA standard. Charging is based on amperage not voltage. The 7805 is capable of supplying 1A and unless your phone is shorted, it will not draw 1A of current. You may need a resistor to limit the current draw such as a 20 ohm 1.25W in series between the output leg and the device. That would limit the current draw to 0.25A. But if you're looking to get a boost than you'd probably want to match whatever your regular charger amperage is (not USB power).

[rmjjensen]

I just looked at my home charger - it's output is rated at 5V 1A. So, the 7805 is right at it's limit. Throw a heatsink on it and it'll be fine and if you're nervous put a resistor on the output leg.

[Sportsguy83]

Originally Posted by rmjjensen

I just looked at my home charger - it's output is rated at 5V 1A. So, the 7805 is right at it's limit. Throw a heatsink on it and it'll be fine and if you're nervous put a resistor on the output leg.

Words of wisdom. Listen to this guy!

[xpicer]

[QUOTE=rmjjensen;608840]That's what the LM7805 does - it's a 5V regulator - no need for any voltage divider circuits and it costs something like $1. You'd install the 7805 and take the output leg (5V) and connect it to the power wire in the usb port. Break out the volt meter, find the existing +5V cut it, and then use the out from the 7805 and feed it to the USB port.


you dont think that the hu might have problems if the orginal power wire coming out of the hu is not connected to anything? like i know on some other modules the voltage/ amperage drop is measured to dictate if the component is connected to the module ???

[Blighty]

Originally Posted by rmjjensen

It's USB - USB is USB - it's 5V and 250mA standard. Charging is based on amperage not voltage. The 7805 is capable of supplying 1A and unless your phone is shorted, it will not draw 1A of current. You may need a resistor to limit the current draw such as a 20 ohm 1.25W in series between the output leg and the device. That would limit the current draw to 0.25A. But if you're looking to get a boost than you'd probably want to match whatever your regular charger amperage is (not USB power).

A USB2 compliant device can take a minimum of 100mA, after which it can request high power mode of up to 500mA. All powered USB compliant host must provide at least 500mA of power.

However, many hosts can provide more than that, and many clients will request more than that.

If the host is providing 1000mA (or 1A), then it should be charging fiarly well. But it might be a case of the device asking for 1.1A or more, and the host just saying 'No dice, I dont have that much' and reverting back to 500 or even 100.

If you have a multimeter you could easily test what you are getting.

[Dezoris]

You wont find an automotive usb port on a head unit over 1 amp usually and the ports on most are .5amp which is why the devices never charge. Some phones and tablets now require 2 amp usb ports as well.

[nab]

The nav app on android is definitely a power hog. I switched to waze and I find my phone keeps it's charge longer. I would get something that goes above 1 amp because I find my phone charges much faster if I plug it into my 2A tablet charger.

[Supermassive]

Originally Posted by rmjjensen

That's what the LM7805 does - it's a 5V regulator - no need for any voltage divider circuits and it costs something like $1. You'd install the 7805 and take the output leg (5V) and connect it to the power wire in the usb port. Break out the volt meter, find the existing +5V cut it, and then use the out from the 7805 and feed it to the USB port.



It's USB - USB is USB - it's 5V and 250mA standard. Charging is based on amperage not voltage. The 7805 is capable of supplying 1A and unless your phone is shorted, it will not draw 1A of current. You may need a resistor to limit the current draw such as a 20 ohm 1.25W in series between the output leg and the device. That would limit the current draw to 0.25A. But if you're looking to get a boost than you'd probably want to match whatever your regular charger amperage is (not USB power).

Hey man I know this may sound silly to ya but you wouldn't happen to be able to draw up a quick little wiring diagram in MSPaint or some other such thing for this? It would be a huge help for those of us who can better visualize this kind of stuff with drawing over words. I am seriously considering doing this since i hate using the silly cigarette outlet for my charger, just want a little more clarification on what goes where so i don't futz it up.