agoraphonics wrote:
1. I have an oldish 12" Macbook Pro A1708.
It appears you have the MBPro 13" (2017) non-touchbar model.
So I bought a new battery and replaced the old one, but I'm still getting the same dead battery icon on the screen as if the battery was never replaced. Tried 2 different power supplies, so that's probably not the issue. It seems there's one of 4 possibilities:
1. The replacement battery was no good. Unlikely, but possible.
Wrong, that is a very likely possibility. The quality of third party Lithium batteries is extremely poor even when purchased from a reputable vendor. I will always choose an original OEM battery whenever possible....this is how bad things are with third party Lithium batteries. Unfortunately an official Apple battery repair is the only way to get an Apple OEM battery.
FYI, when Apple replaces the battery, they also replace the entire Top Case Assembly which includes the palmrest, Keyboard, Trackpad, and Battery since the battery is glued to the underside of the palmrest & Trackpad.
2. I installed it incorrectly. I think this is pretty unlikely too - I disconnected and reinstalled it again to be sure.
3. There's some trick I'm unaware of to get the new battery to be recognized.
These Apple USB-C laptops have a lot of quirks even when using the original Apple battery. I have seen these Apple USB-C laptops just show the battery icon on the screen (sometimes not even showing the battery icon). Sometimes the laptop will magically & mysteriously power on & boot after sitting for 15 minutes with the power adapter connected.
On the non-touchbar model, you need to make sure the battery flex cable is properly connected on both ends. This cable can easily pull loose while attempting to connect it to the Logic Board, but the other end has a connection on the battery board too. These little connectors are also very easily damaged where the locking lever can pop off, or even the thin plastic edge of the connector can split off....you may not even notice it if you are not paying close attention to it as you move the locking lever.
4. There's a power management hardware issue that needs to be fixed.
Yes, that is also a very likely possibility.
Besides the replacement battery possibly being bad....unfortunately there is no way to know or confirm this without testing that battery with a known good Logic Board.
I find the USB-C ports on these Apple USB-C laptops many times will have accidental liquid damage on the connectors. This damage many times is not visible even when looking closely at the contacts through the port opening. Many times I will think the USB-C port is fine until I remove the Logic Board from the laptop to get a clear unobstructed view of the contacts on the USB-C ports. It is very dangerous to remove the Logic Board on this model since the headphone jack cable connection to the Logic Board is usually very tight & difficult to disconnect. I actually accidentally ripped the connector from the Logic Board because it was so tight...I was being extremely careful since I already knew this was difficult to disconnect, yet I still broke it off....I had done this procedure hundreds of times while supporting my organization's thousands of Macs.
Another possibility is the USB-C ports are worn and the charging cable is not fitting snugly enough. A little known design defect on the 2016 & 2017 models is the USB-C ports wear down very quickly with use so that cables no longer fit snugly. Unfortunately with the non-touchbar model, these ports are an integrated part of the Logic Board so they cannot be replaced.
It is also the protective circuitry for the USB-C ports has been damaged or became defective. While each port has its own circuitry, some failures will affect both ports due to how they are designed for power & charging the laptop.
You can try unplugging the charger from the electrical outlet for a minute to reset the charger's internal circuitry. You can also try rotating the USB-C connector of the charging cable 180 degrees upside down in case the USB-C port is half bad (seems crazy, but I have personally seen this work). You can also try another USB-C port, charging cable, and power adapter (make sure the charger is at least 61W+). Disconnect all external devices and connect the charger directly to the laptop since adapters, docks, hubs may not allow the full power of the charger to reach the laptop. Here is an Apple article for USB-C charger troubleshooting:
If your USB-C power adapter isn't charging your Mac laptop - Apple Support
FYI, the SSDs on this non-touchbar model have an extremely high rate of failure. Also, the display and keyboard have well known hardware issues due to design defects. I personally would not put any more money into this laptop.
