Here's the next item on my "to-fix" list while home for the holidays...
I have before me a Motorola E815 cell phone which will not charge. The battery is fine, just the phone won't make a connection to the charger. I found an old LG cell phone with battery, which works fine.
Since every single cell phone I've ever seen uses a 3.7V Li-Ion battery, and since I don't have a programmable voltage supply with me, I figured I could use the LG cell phone to charge the Motorola battery. The LG cell phone and its battery have 4 contacts:
| | | | NEG NEG MYSTERY POS
and the Motorola cell phone has 4 contacts as well:
| | | | NEG NEG MYSTERY POS
I figured I could just connect the +/- terminals of the LG phone to those of the Motorola battery, and the Positive terminals together, and then the LG phone would see it has a drained battery and merrily charge it up.
Not so! When I did this, the LG phone said "Use genuine battery!" and refused to charge it. WTF?!?! It seems like there's some kind of "counterfeit detection" circuit in the battery to make it harder to make cheap knockoff batteries. I assume this comes from the "mystery" contact. Is there information somewhere on how to fool this idiotic counterfeit detection circuit?
Thanks,
Dan