Thanks Grindale and Angelii, I had the same issue pop up (a Motorola phone giving me

an "Invalid Battery" message). Used your solution and it worked! Thanks!

Take your case off and battery out.Let it sit.Put battery in and leave phone off.Charge till 100%.IT WORKS^.^ (I speak from experience)

Hi Brenda. Do you have a Motorola phone? This issue seems to be happening with Motorola phones. Please try this solution and confirm if it works.

- Remove the battery, let sit a minute....
- Plug the battery back in but don't boot the phone, leave it off.
- Plug in the charger and run it until the battery recharges fully.
- Turn on the phone and all should be well as the battery's IC has reset to
the full charge state from its state of confusion.

The IC in the battery talks to the phone over that third contact. It's
telling the phone jibberish, which is an invalid battery because it's not
what the phone is looking for.....

The phone won't charge or use an "invalid battery" which may destroy it, so you get no battery symbol.

If this doesn't work, replace the bad battery with a new one. They're
really cheap off the net, especially the recycled ones from recycled
phones, which are usually just fine. source