Fuze battery wires black/blue/red

I took apart my fuze with a dead battery.

I see theres a black, a red, and a blue  wires.

The black is connected to the circuit board as - negative.

The red is + positive.

What’s the blue wire for?

Inside the li-poly battery is a small circuit board that contains a microcomputer IC that controls/monitors the battery charge. The blue wire goes from the controller board to the player.

Message Edited by 14124all on 10-08-2009 10:12 AM

@14124all wrote:
Inside the li-poly battery is a small circuit board that contains a microcomputer IC that controls/monitors the battery charge. The blue wire goes from the controller board to the player.
Message Edited by 14124all on 10-08-2009 10:12 AM

 

Theres actually no IC inside the Fuze’s battery.  The monitoring is provided by an AMS power management controller on the SOC.  The wire in question is connected to a thermal diode to monitor the battery temperature.  

I just have to be sure before I clobber the battery.

Maybe I should just carefully pry open the battery.

 Theres actually no IC inside the Fuze’s battery.  The monitoring is provided by an AMS power management controller on the SOC.  The wire in question is connected to a thermal diode to monitor the battery temperature.  

Very good info.  I too was wondering what the 3rd wire is for.

Would you happen to know whether it would be possible to remove a dead battery and then power the Fuze with external batteries (three 1.2 volt nicad batteries would total 3.6 volts ) by just connecting to the black and red wires?

Or will the blue wire being connected to nothing disable the Fuze thinking it is in overtemp condition?

Thanks,

Sky

Skyglider , I actually did something like that to a cheap Chinese mp4 player and left the third wire “unattended” by connecting it to the 3AAA battery box. Not sure what processor it was, but I’m certain it was not AMS. The combination works OK for a month, but not sure how long it would last though… (The box just glues to the back side) :slight_smile:

@lee88 wrote:

I just have to be sure before I clobber the battery.

Maybe I should just carefully pry open the battery.

 

 

That doesn’t sound like a very good idea! :dizzy_face:

Do not attempt to pry open the battery or puncture the battery pack!

LiPo batteries have a high energy density and are very reactive.  The sensing wire is important to protect against overheating.

µsansa

Skyglider , I actually did something like that to a cheap Chinese mp4 player and left the third wire “unattended” by connecting it to the 3AAA battery box. Not sure what processor it was, but I’m certain it was not AMS. The combination works OK for a month, but not sure how long it would last though… (The box just glues to the back side) :slight_smile:

After reading your post, I had a memory jog.  In electronics floating inputs lead to unreliable operation.  So it would be better to connect the unused blue lead to ground via a 1K resistor.  Since your’s worked OK for a month while floating, it appears that a low (ground) voltage = temp ok, while a high (+3.6 volts through the resistor) = high temp.

It would be a simple matter to connect the blue wire to either through a resistor, depending which works.

The main thing is that the blue wire does not have to be connected between the batteries to get 1.2 or 2.4 volts used as a biasing voltage.  Evidently not.

 Thanks for your input!

Sky


Do not attempt to pry open the battery or puncture the battery pack!


Love your sense of humor!

Sky (who’s still chuckling :o) )

If its just a thermal resistor or thermal diode, why don’t I just wire that with a new battery?

@skyglider wrote:


 Theres actually no IC inside the Fuze’s battery.  The monitoring is provided by an AMS power management controller on the SOC.  The wire in question is connected to a thermal diode to monitor the battery temperature.  


Very good info.  I too was wondering what the 3rd wire is for.

 

Would you happen to know whether it would be possible to remove a dead battery and then power the Fuze with external batteries (three 1.2 volt nicad batteries would total 3.6 volts ) by just connecting to the black and red wires?

 

Or will the blue wire being connected to nothing disable the Fuze thinking it is in overtemp condition?

 

 

 

 

 You can trick it into thinking theres a temperature probe using a resistor between ground and the sense line in order to fake a thermal diode.  However you will probably destroy your player if you try to charge a nicad battery, so you should not do this with anything other then a DC power supply running at ~4v, and you absolutely should not plug it into a USB port while doing this.  

@skyglider wrote:

Very good info.  I too was wondering what the 3rd wire is for.

 

Would you happen to know whether it would be possible to remove a dead battery and then power the Fuze with external batteries (three 1.2 volt nicad batteries would total 3.6 volts ) by just connecting to the black and red wires?

 

Or will the blue wire being connected to nothing disable the Fuze thinking it is in overtemp condition?

 

@ Saratoga wrote:

You can trick it into thinking theres a temperature probe using a resistor between ground and the sense line in order to fake a thermal diode.  However you will probably destroy your player if you try to charge a nicad battery, so you should not do this with anything other then a DC power supply running at ~4v, and you absolutely should not plug it into a USB port while doing this.  

My plan is to use rechargeable AAA batteries in a battery holder.  The batteries would be removed and recharged in a free standing battery charger.   I love eneloop batteries since they hold their charge even while being stored.
Sky