Chosen Solution
You know what the problem is. El Cheapo replacement battery. (It probably only weighs half of what it should). The fix is to use a quality battery replacement. I don’t understand why need us to tell you this, you already know! Your Machine uses an A1382 battery. iFixit is out of stock. Try these folks. Products are good and shipping is very good. http://www.ebay.com/itm/RELACEMENT-BATTE…
Try calibrating the old one. also return it and get an OEM battery. Hold the Option key and click the Apple menu. Choose System Information. Under the Hardware section of the System Information window, select Power. The current cycle count is listed under the Battery Information section. see if that says its still good. If it does try a calibration
