Charging battery via usb question

Harsky · Post by **Harsky** » Wed Apr 18, 2007 7:09 am

So I decided to try the whole, "MP3 player in a NES controller" mod I read ages ago. I bought a cheap MP3 player since it doesn't have an LCD and a cheap NES controller. The MP3 player is powered by a single AAA battery but I realised that if the battery runs out, I'm going to have to go throught the hassle of removing the case and then putting in a new battery. I was wondering if it could be possible that I could put in a generic rechargable battery in there and then have it recharge by plugging it into a USB port of a PC or one of those power adapters which you can use to plug in USB devices?

johnbjuice · Post by **johnbjuice** » Wed Apr 18, 2007 9:41 am

Well, a USB port puts out 5v. A typical rechargeable is 1.2 volts. So...

I think there's a way, but I don't know. You'd have to convert the voltage.

bgnome · Post by **bgnome** » Wed Apr 18, 2007 10:45 am

you could always get one of these:

Harsky · Post by **Harsky** » Wed Apr 18, 2007 11:25 am

bgnome wrote:you could always get one of these:

I'm a bit worried that if I buy it, it won't fit into the Nes controller.

Post by **Sparkfist** » Wed Apr 18, 2007 1:23 pm

I have an Energizer 4 AA recharge station that came with a car adapter, so I'd say yes. You could hack one to make a charger, but I think that would be more work then you'd want for the project.

If you were to get a battery pack that was 5-7.2 volts then you could likely make a car adapter to rechargeable much easier. You'd have to go about the same route but as you don't have to step the voltage down so much it should be simpler and smaller.

@Harsky, I've seen those USBCell batteries mentioned. I'll have to see about finding where some are sold. I live with my computer and I'd make better use out of those then any other rechargeable AA.

johnbjuice · Post by **johnbjuice** » Wed Apr 18, 2007 2:06 pm

Those usb batteries are AA sized. At least mine are! (=

Didn't think about those. Would work!

JKO-K6 · Post by **JKO-K6** » Wed Apr 18, 2007 3:25 pm

Or why not doing something like this?

demonofaj · Post by **demonofaj** » Wed Apr 18, 2007 3:29 pm

Amperage is a problem too.

JKO-K6 · Post by **JKO-K6** » Wed Apr 18, 2007 3:30 pm

Amperage is a problem too.

How much comes from a USB?

Post by **gannon** » Wed Apr 18, 2007 3:32 pm

It depends on the motherboard/settings I think, some can handle only 500mA while others can do ~2.5A

timmeh87 · Post by **timmeh87** » Wed Apr 18, 2007 4:17 pm

if you were going to go through the trouble of getting a 5v - 1.2v adapter, then forget charging the battery with it, just hook it up to the mp3 player permanently.

It actually isn't much trouble at all. you can use the pth08000 or whatever, the same one for the N64's 3.3v line. Its on the wiki. Using a different resistor, you can make it output 1.2v. You could just tap the 5v line on your motherboard if you want to get fancy, and not have to use up a USB port.

Harsky · Post by **Harsky** » Wed May 16, 2007 8:02 am

bumping this topic. Can't I just wire from the +5v of the USB to the rechargable battery instead or is it just a disaster waiting to happen?

timmeh87 · Post by **timmeh87** » Wed May 16, 2007 9:48 am

it would probably be ok, but then you are responsible for manually ending the charge every time. if you let it keep charging it will heat up a lot and eventually destroy itself

Post by **gannon** » Wed May 16, 2007 10:37 am

Don't forget a current limiting resistor, would hate for you to blow a fuse on your PC or have your batteries catch on fire.

HotDog-Cart · Post by **HotDog-Cart** » Wed May 16, 2007 1:49 pm

Heh, Im doing a Mp3 in a NES controller too. Thats what my "NP3" is.

Same problem as you, but AAA's tend to last for a while with my RCA Lyra.