EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: Seekonk on April 30, 2016, 07:50:07 pm
-
I just got a new replacement battery for an old LG cell phone. Upon unpacking the battery measured 0.00V. Pack has three terminals and don't think it is likely there is any electronics in the pack to disconnect the pins at low voltage. Seems like that would be in the phone. Normally I wouldn't give this much thought, but only one vendor on ebay even offers this battery. I popped it in the phone and for a couple minutes it acted like a near shorted battery with a blue LED keyboard light barely on. Then a couple minutes later the display came to life. Shortly after that measured the battery at 3.7V. My understanding was that once these dropped below 3V the cell would get permanent damage. This is a hard battery to find and wondering if it has a chance since it is new an apparently better quality (made in Japan). Any thoughts?
-
Likely the protection kicked in so it read 0v. If it's a rare battery it could have been in storage for months. If it took only a couple of minutes to reach 3.7V it's unlikely to be damaged and was just protected from further discharge.
-
3 pins means it has on board protection, like every cell phone battery aside from those glued into the case ( fruit company). The protection turned off the output as it went below 2V9 or so and then only allowed charging via the one body diode, till it got high enough to enable the second mosfet to enable discharge. If it lasts as long as the regular cell in use it will be fine.
-
Even the fruit company batteries have a protection board directly on the tabs.
-
At least you are sure it had a protection PCB.
I got a few cheap ones before and these were what I got. http://www.quan-diy.com/misc/battery/fake.htm (http://www.quan-diy.com/misc/battery/fake.htm)
-
Some batteries have a "shipment mode" that needs an initial charge to activate.