5V Battery pack- homemade

[psykopyro]

I recently completed my Altoids iPod charger, and i must say I love it. I have another mp3 player, generic brand, that runs off of a 5v ac adapter plug.

I looked around and the only option is a 4.8v pack. Is this enough?

Also, the majority of them seem to be four rechargable C batteries in a plastic shrink wrap. How are these things wired? If i got 4 reguilar rechargable C batteries from Target, four holders from radio shack that hold a C battery each, i could wire them up to a dc jack that goes into my mp3 player, and whenver the batteries run out, i pop them out of the holder and put them in a household battery charger.

How's that sound?

[FeelTheFire]

you can use a straight up 9V battery and slap a 5V regulator on it. That's how people who have been making backup USB chargers usually do it, since USB must take 5V, while firewire can take anywhere between 5 and I think 15V. I found instructions on how to make a 5V usb charger somewhere, I'll look for it for you.

[charade]

ill try to make a usb one once you find it.

[psykopyro]

like the first item on this page-

http://www.eidusa.com/Electronics_Voltage_Regulator.htm

????????????

[psykopyro]

here's a simple diagram i drew out- think it would work?

http://img208.echo.cx/img208/2497/diagram5jd.png

[FeelTheFire]

et voila- the 5V battery pack made with a 9V battery:

http://ipod.hackaday.com/entry/1234000270029372

and the altoids tin firewire pack:

http://home.carolina.rr.com/trevorshp/battery.htm

please note that the second option ONLY works with firewire and you have to make triply sure that the positive line goes to pin 1 of the firewire and the negative line goes to pin 2. Since that battery configuration supplies 12V, which USB will not support. USB must have 5V to run, while FireWire can run off anywhere between 5 and 12 V I think.

I'm going to try to throw together an altiods firewire charger this weekend, and I'll rope the father in for help if I need it. Finally put that electrical engineering degree to good use!

If you have a target near you, they have a whole display of batteries for $1 a package. Pick up a pile if you're planning on using one of these to keep costs down, unless you plan on using rechargeables.