3 pin cell phone battery question

theAnonymous1 · 16th December 2006, 01:03 AM

I have some cell phone batteries I plan on using with headphone amplifiers. These have 2 positive contacts, one goes straight to the battery and the other one is the output from the small circuit board.

My question is which one is for charging and which one if for the output?

I've searched the net for almost an hour now and can't seem to find any info.

DigitalJunkie · 16th December 2006, 01:08 AM

Go straight to the battery if you can.
I always have issues with those battery "watchdog"/controller boards giving me grief.

jc2 · 17th December 2006, 03:48 AM

Unless you know what you are doing and know that you aren't going to do anything that creates an unsafe situation I wouldn't recommend bypassing the monitoring circuitry.

One three pin cell phone batteries you generally have ground, the positive battery voltage, and the 3rd is either some sort of serial communication, or more likely a thermistor connected to ground that is used for identification and as a temperature monitor.

TwoSpoons · 21st December 2006, 04:47 AM

If those are Li-ion batteries, then DO NOT bypass the safety cutoff circuit! If discharged too far Li-ions can go into destructive self-discharge.

Have you considered after-market Ipod replacement batteries? They're way cheaper that cell phone batteries, and they have a nice wire with a plug on the end, instead of flat contacts.

16th December 2006, 01:03 AM	#1
theAnonymous1 diyAudio Member Join Date: Feb 2004 Location: Anonymityville	3 pin cell phone battery question I have some cell phone batteries I plan on using with headphone amplifiers. These have 2 positive contacts, one goes straight to the battery and the other one is the output from the small circuit board. My question is which one is for charging and which one if for the output? I've searched the net for almost an hour now and can't seem to find any info.

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16th December 2006, 01:08 AM	#2
DigitalJunkie diyAudio Member Join Date: Apr 2003 Location: Portland,Oregon Blog Entries: 4	Go straight to the battery if you can. I always have issues with those battery "watchdog"/controller boards giving me grief.

17th December 2006, 03:48 AM	#3
jc2 diyAudio Member Join Date: Dec 2001 Location: Atlanta, Georgia	Unless you know what you are doing and know that you aren't going to do anything that creates an unsafe situation I wouldn't recommend bypassing the monitoring circuitry. One three pin cell phone batteries you generally have ground, the positive battery voltage, and the 3rd is either some sort of serial communication, or more likely a thermistor connected to ground that is used for identification and as a temperature monitor.

21st December 2006, 04:47 AM	#4
TwoSpoons diyAudio Member Join Date: Oct 2004	If those are Li-ion batteries, then DO NOT bypass the safety cutoff circuit! If discharged too far Li-ions can go into destructive self-discharge. Have you considered after-market Ipod replacement batteries? They're way cheaper that cell phone batteries, and they have a nice wire with a plug on the end, instead of flat contacts.