replacing the battery on a 1st gen Nano

[woodensoul]

I picked up a couple broken Nanos off eBay thinking  it would be a quick fix with a $5 battery.  Well I've been having the same problem with both Nanos.  It seems like the batteries won't charge even after leaving them plugged in for over a day.  I get the "Charged" icon indicating the battery was fully charged, but when unplugging the player from the cable it immediately dies saying the battery is empty.  On one Nano I simply twisted the wires together using the wires from the old battery and the other I soldered them directly to the board. 

After reading several posts on getting a Nano working again after the battery has gone completely flat and trying the methods mentioned with no success, I'm beginning to wonder if the charging circuitry is the problem for both players.  One thing I haven't tried is leaving Rockbox running while attempting to charge with a wall charger.   

Has anyone been successful in replacing the battery on a Nano and what procedure did you follow to get it working again?