External charges n900
 

Hi there everyone,

I seem to have a problem.

Yesterday i received my ordered charger. it is a charger where i can put in 4 x AA batteries and the output is a USB port. so i can connect the n900 usb cable and should be able to recharge it.

But for some reason the charging is not working. the n900 is not reacting when i plug it in. when i pull it back out the screen backlight goes on.

With the charger i can recharge my bluetooth headphones and Sony psp without any problems.

Also strange is the fact that when the n900 is shut down and i connect the charger then the n900 starts flashing the orange LED (normal when loading) for a few seconds. the OS starts and shuts down again. and the charging stops. (battery was 70% full when testing so the n900 wasnt shutting down because the lack of power in the battery)

Does anyone know why its not working? Someone i know has one too and on his phone it works perfect. Could it be my software on the phone?

One more thing. the n900 charges fine on the usb through computer and the normal charger.

Re: External charges n900
 

I would assume you're using a USB data cable, with the two data pins intact, to hook up your charger to your device.

If so that's your problem, there are several very long threads on the forum discussing the ins and outs but basically if the USB cable you plug in has the two data pins available, the device thinks its connected to a USB host and tries to negotiate for the charging power. As it's actually connected to just a charger, there's nothing to negotiate with so this fails, and it wont charge.

Dedicated charging USB leads have unconnected data pins, which the device will recognise and simply draw a charge from.
Your choices are to either find a dedicated USB charging lead (they exist) or modify your existing lead by soldering the two data pins together.

Re: External charges n900
 

I've also seen posts here where someone made an adapter he could put between the charger (cable) and device.

Personally I'd just prefer it if they rewrote the the firmware to assume standard USB current if connected to a charger that cannot negotiate, but that might be in violation with the new microUSB charger standards. Since that's not going to happen, I'd look through eBay for a special microUSB charger cable that is specified like the previous post suggests.

Re: External charges n900
 

this will help allot! the person i was talking about made his own charger and soldered the usb cable directly to the print. so if you leave the two data cables in the middle unconnected it shoudl be fine?

Re: External charges n900
 

No, they have to be shorted together (or with a small resistor).

Re: External charges n900
 

many thanks for this great help im gonna try this out tonight

Re: External charges n900
 

Btw, I did a bit of searching, and there are some products that should help with these so-called "dumb" chargers:

This should work: http://usbfever.com/index_eproduct_v...oducts_id=1746
I think this should work, too: http://mobile.brando.com/mini-usb-to...c0704d003.html
Both are unconfirmed.


Btw, I feel I should direct you to a thread where they discuss several possible solutions, both hacks and adapters, though many unconfirmed.