Supplying 4.5 volts to something that takes 5 volts?

[Lord Ned]

Gotta get this answered really quickly.

I'm going on vacation for 5 days without a computer, and thus will have no way to charge my Mp3 player. I can figure out a way to get 4.5 volts to it (3 Double A's). Normally it just takes the 5v provided by the USB plug on a computer, but if I can provide 4.5 volts, will it still charge?

Do i run the risk of damaging my mp3 player by trying to charge it with 4.5 volts instead of 5?

Thanks.

[xRyokenx]

I don't see why it would so long as you don't up the amperage or anything... it won't charge as fast with the AA's but it should still charge.

[Spawn-Inc]

don't think its gonna work, needs 5 volts. you can try it and see what happens but i doubt it will work.

[Lord Ned]

Good, becuase it's either that, or five, long days of silence. (After the first 20ish hours of playback! :D)


Now to chop a male to female usb cable up, so I can wire up 3 Double A batteries.

Any suggestions on how to hold two wires onto 2 pins in a USB Adapter? (Since I don't have a female to female USB adapter and a hacked off usb mouse cord)


-edit-
Dough I just got posted ahead of time'd. (Er..?)
The difference of .5 volts is pretty meager though. Unless anyone else has any idea how to get 5 volts with batteries without any resistors or other stuff that needs to be soldered?

[xRyokenx]

Maybe try here (www.wikipedia.org) for some more info too.

[Lord Ned]

Wikipedia probably isn't going to help here?

[xRyokenx]

Just look up a basic electronics article, lol. I'd do so for you but I've got too much on my mind right now.

[Lord Ned]

I don't think they'll tell me a yes or no about lower voltage.

[xRyokenx]

Not an exact answer for your exact question but it's bound to have some info there somewhere. I have a charger that was for my Pocket PC but also works for my Zune and it has a lower amperage. It just charges slower. Also, I used rechargeable batteries in a flashlight once and it worked, just wasn't as bright as the voltage was lower.

[Lord Ned]

I'll have to try it. I just gotta find a way to keep the wires on the two pins. :S

[xRyokenx]

For that you could try soldering them... or if not good at that or if that won't work... maybe some glue or something?

By the way, sorry if I haven't been very helpful, I've had a really odd day and I've been "out of it" all evening.

[Lord Ned]

Yeah, but I don't want to permantly damage the usb cord on my only male to female. :S

(Course there probably pretty cheap but whatever)

I may just have go without music.

[SgtM]

Take a 9v battery. Put a resistor in the middle to knock it down to 5v. Use a resistor calculator to find out what resistor you'll need. (You'll need the amperage of the device you want to charge) http://led.linear1.org/1led.wiz

[weazel6265]

Hopefully I'm not to late for your trip.Since you don't want to work with resistors, if I remember right from my physics classes a while ago, batteries add in serial but do a 1/x in parallel.

I think what would work out for 4.5 v would be to have 12 AA batteries in the following pattern: 6 serial sets of 2 parrallel batteries each (i.e. have 2 batteries in parrallel, then connect 6 of those in serial)
If my math works out it should be:

1/.75=1/1.5+1/1.5

and then 6*.75=4.5V

I have absolutely no clue what this would do to the current though, so hopefully someone else can chip in

[NightrainSrt4]

Your math looks right, assuming your equations are correct. I don't know if they are, but the math looks right.

But he is still left with the issue if 4.5V will work for something that wants 5V, of which I can't chime in about, as electricity is not my best area of knowledge.

[xmastree]

Since you don't want to work with resistors, if I remember right from my physics classes a while ago, batteries add in serial but do a 1/x in parallel.
NO!!!
Don't do that!

Two 1.5V batteries in parallel will still give 1.5V, but twice the available current.

What's wrong with something like this? (http://l8shop.net/products/USB-Mains-Charger-Adapter.aspx)

Edit: Since the battery in the MP3 player is probably a 3.6V Lion cell, then it may well charge from a 4.5V source. However, using 3xAA isn't a good idea as they may only have the capacity for one or two charges. Use bigger ones instead, like D cells.

[weazel6265]

Wow, that was stupid, I did the exact opposite of what you wanted, now that I look at it, and apparently it will fry your electronics, so don't listen to me at all.

[xRyokenx]

Wow, that was stupid, I did the exact opposite of what you wanted, now that I look at it, and apparently it will fry your electronics, so don't listen to me at all.

It was just a simple mistake dude, don't make such a big deal out of it. ;) Happens to the best of us.

[NightrainSrt4]

Hey, at least your math 'looked' right :D

[John5247]

four fully charged NiCads or Ni MH at 1.2volts each is 4.8 volts - much more likely to work - but you need to buy 4 recharrgeables and a charger ...!
As long as you are certain the wires are electrically touching the USB pins, you can blob superglue over the joint - you just need to keep it all still with Blu-tak (under the plug a back down the wire a bit) untill the glue dries ... or get a soldering iron!
much cheer
John

[xmastree]

If he's doing to buy 4 NiCds and a charger, he might as well buy the right charger for the device. Like in the link I posted (http://l8shop.net/products/USB-Mains-Charger-Adapter.aspx) earlier.

[Lord Ned]

Kay trips over, I Just didn't use it and ended up with half battery life left at the end. :S

[crenn]

4 AA batteries and a 5v voltage regulator works better.