It it possible to get rockbox to force battery to charge?

[Razor512]

I have a sandisk sansa fuze V2, and recently replaced the battery.

the battery used was http://www.cameronsinobattery.com/916-sandisk-sansa-fuze-4gb-8gb-battery/

While the battery will power the device, and it will get a battery life remaining readout,it is unable to charge it. (it will say that it is charging, but it will never actually charge.

In testing with a multimeter while charging, even though it will say that it is charging, it does not actually send the 4+V into the battery to actually charge it.

If I solder the old battery back in, then it works just fine.  Is something wrong with the battery, or is there something special that needs to be done with the MP3 player first?

[saratoga]

Is the thermistor wire connected?  Does it actually have the same resistance as the old sandisk battery?  If not, the charge controller may not charge the battery. 

[Razor512]

it is connected.  I did not measure the resistance on the original battery, but  did measure the voltages, and both were about the same, (seemed to match the cell voltage, though that center wire does not give out much amperage.

In trying to test the resistance between  the center wire, and +,  I am unable to get a reading

in testing the resistance between the white and black wire, I get 9.8 kohm

[Razor512]

I just did a test of the resistance on the stock battery (though it was still wired to the device, and got 99.8 kohm

is the sense wire based entirely on resistance, or is there other data?, would it work if I wire a 100kohm resistor in-line with that wire?

[saratoga]

Yes that should do it, although you will probably lose thermal protection.

[Razor512]

thanks, I wired in a 100kohm resistor, and it worked. due to the shape of the cell, there is enough space to cut the wire, then solder it in line with the wire, and then tape it down on the front of the battery. It now seems to be charging properly.