Battery died while plugged in to high-power usb port.

Ian Darwin ian at darwinsys.com
Sun Aug 5 19:23:35 CEST 2007


Erik wrote:
> This morning I woke up and found I couldn't turn on my neo... even
> though it was plugged in [usb] all night!  It was plugged in directly,
> as in no hub, and yes, the PC was on overnight.
> 
> I'm not sure what happened... I was playing with gsm and bluetooth
> [ssh'd in over bluetooth] when I powered it off.  I probably just put
> it to sleep, actually, not hard off.  So possibly the bluetooth was
> still on drawing power, and maybe the gsm was still alive, and the cpu
> was keeping its memory warm too.  So possibly this was taking more
> than 100ma?  I didn't even think I had anything to worry about since
> it was attached to USB 5V that should be able to put out 500ma.  I
> figured it'd be fine to leave it in that low-ish power state
> overnight.
> 
> I'm attempting to charge the battery now, the Neo 1973 emergency
> charging way listed on 
> http://wiki.openmoko.org/wiki/Neo1973_Battery_Charger So I have my
> fingers crossed that it'll come back to life.  

The page you cite implies that you can use a reasonably arbitrary USB 
charger, e.g., from a Blackberry, to charge your Neo:

"An alternative method is used if the proper charger for the Neo is 
used. If the Neo measures 48kohm +/- 1% between usb pin 5 and ground, it 
will detect the dumb charger and use it for fast charging."

Has anybody tried this, specifically a Blackberry charger?

> 3. Should a voltage always appear on the +/- terminals of the battery,
>    or does that third pin need tickled in some way to get a voltage
>    out?

I had my battery out the other day when in similar circumstance, and 
measured around 3V across the +/- terminals with no tweaking, so I 
suspect that it should always appear.



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