Gigabeat F40 Charging question

[PCpr0gramer]

I took the USB cable for my Gigabeat and cut it in half (I'm not dumb, I have multiple,) to use as input for a battery based charger for my player.

IE: |Batteries|----usb cable----->|Player|

The only problem is that the player does not accept a charge from USB unless it is 'talking' to the computer. Is there any way to get around this besides using the 5V input up top to charge from external batteries?

Thank you for all of your help.

[Mad Cow]

My Gigabeat charges fine with an AC USB charger, which is electrically the same as a USB cable attached to batteries. Remember that the gigabeat has to be turned on to charge through USB. Why don't you want to use the 5V plug? It's so much more practical.

[PCpr0gramer]

The AC adapter does work, and I could use it to charge from batteries, but I have more than one usb cord, and only one AC adapter cable so I don't want to go and cut it up. It does charge when hooked up to the computer through usb, just not when its hooked up to batteries through usb. Thank you for your input though.

[markun]

Remember that the gigabeat has to be turned on to charge through USB.

This is not true. The Gigabeat charges over USB, even if turned off. You just don't see it on the display. Just try it: remember the battery percentage and turn the player off, leave the USB cable connected for a while and turn it back on.

We could display a charging screen if we ever flash our own bootloader, but that would also slow down the charging of course.

[PCpr0gramer]

Thanks for the info. One last thing before I try it out, I know it takes 5V in through USB. At how many volts do I run the risk of doing damage?

[Chronon]

I would probably want to regulate it at 5V.  Is there a reason you want to go higher?

[Mad Cow]

Remember that the gigabeat has to be turned on to charge through USB.

This is not true. The Gigabeat charges over USB, even if turned off. You just don't see it on the display. Just try it: remember the battery percentage and turn the player off, leave the USB cable connected for a while and turn it back on.

We could display a charging screen if we ever flash our own bootloader, but that would also slow down the charging of course.

I never knew that, thanks for the info. And al this time I was charging through USB with the player turned on.

You don't need to cut up your AC adaptor cable, I went to radioshack and just bought a plug the same size and soldered on the wires.

[PCpr0gramer]

Thank you everyone for your responses. The only reason I went higher was because the only way to hit >=5 volts in 1.5 increments is to go to six. I'll describe my final design which works.

-First, I cut the cable for the AC adapter and took off the male jack.
-I then took an extra USB cable I had and attached the male jack to the large end (one that goes into the computer) of the USB cable.
-Next I hooked up a battery holder (4 batteries) to a USB port, I attached the port to the positive and negative ends of the set of batteries.
-I took another USB port and attached it to the end of the AC adapter.

Final setup:
|BATTERIES|=|USB PORT|
and
|AC ADAPTER|=|USB PORT|
|USB CONNECTOR|-------|Male AC jack|>Player

^can be attached to either, and charge from:
a. the computer
b. battery holder
c. AC adapter

I plan on installing a 5V regulator on the battery pack. I hope some people found this little project interesting. I just wanted to add a little mobility to my player.
I would just like to say that rockbox is an amazing project. I run my business from my mp3 player now. It has copies of all of my crucial programs so I can run them anywhere, on anyone's workstation. I have actually had people become so interested in my rockbox'd gigabeat that they have bought one on ebay and given it to me just to install rockbox on it. At school I get requests to rockbox peoples iPods. Needless to say open source architecture is the way to go. Thank you to all of the developers.

[Mad Cow]

For the voltage issue, you could go 4 rechargeable batteries, that would equal 4.8v, which would be nearly perfect.

[scharkalvin]

When I plug the USB cable into the gigabeat (even when the cable is connected to an ac charger and NOT a computer) the player displays the USB connection icon.  

I've been thinking of making a cable with an USB "A" end and a 1/8" phone plug end to just charge the player from the 5v input jack with USB.  But this would NOT work with a computer, only with an AC or car charger since the computer would probably not supply enough power to charge from it's USB.

I'm sure the player is being charged (at a slower rate) while I have it plugged into the computer via USB to download stuff.

[Mad Cow]

It won't go into USB mode if you hold the "A" button I think. It might be "Menu" though.

[GodEater]

It's "Menu" that you hold while you plug the cable in.