What's the function(s) of the extra contacts on so many cellphone's batteries?

[Benny7440]

Someone gave me a Zune device telling me that it was an iphone & I thought it was an ipod instead. It took 2 different persons trying to investigate this device & more than a week for me to get it right. Obviously, the batt. was fully discharged & there was no cable or base for it...

I watched a video showing how to open it and got access to the batt. but it took just about 3.2 V after 3 trials. I then took a cellphone batt fully charged & managed to get access to its programs: it still works. The batt didn't lasted the amount of time I needed, so I found other cellphone batts (discharged) and thought of charging all of them and stacking all in parallel to increment time duration. Some of the batts have 3 contacts & others 4.

My question now is how to charge them because their respective phones don't exist anymore or there're problems with their charger, cables or the phone itself? I know that maybe I can't use all of them because may not take a charge anymore, so I need to make sure that each one can be charged before making a "pile" of them. Once the pile is made then they must be charged either individually or at the same time, (this last scheme demands a more powerful power supply...).

Think I'm not the first person to face this situation and more than one solution may be found. Thanks in advanced for any help with this!

 

[Ylli]

Recycle all these batteries and buy the proper one with the proper charger. Otherwise, you are asking for catastrophic battery failure and perhaps a fire. Li-Ion batteries are not something that can be charged/discharged willy-nilly.

 

[Benny7440]

Recycle all these batteries and buy the proper one with the proper charger. Otherwise, you are asking for catastrophic battery failure and perhaps a fire. Li-Ion batteries are not something that can be charged/discharged willy-nilly.

I used to be an electronic technician in a computer factory by the late 70's and early 80's, so I'm inclined to use my own judgement after considering all or most of the available data. Having said so, what I want is to gain access to the knowledge applicable in this case.

I know that Li-Ion batts are dangerous and should be handled carefully both, physically & electronically. I might do, at the end, as you suggest but, for now, I want to try to give those old batts a chance. In any case, this is so old that its' parts are scarce and pricy: not a good general approach.

 

[WHONOES]

Li-ion batteries need to be charged in a certain way, paying very very close attention to the charge voltage per cell plus a method of current limiting, termination of charge and preferably some thermal feedback that can also be used to terminate the charge process.

 

[bertus]

Hello,

Have a look at this video and see waht happens at about 4:00,

More info on the lithium batteries can be found in the battery university:
https://batteryuniversity.com/learn/

Bertus