Chosen Solution
So I know this has been asked several times and it always ends up being solved by either a new battery or a new battery data cable. In my case, I have installed a new battery, no good result (still no battery detected). And I’ve also pulled a known good battery data cable from an exact match donor macbook (2017 Fn key). So I’ve installed a brand new battery and a “not new but working in another machine” data cable and still can’t get the battery to detect in this system with a new logic board. Here I am hoping somebody may have a slightly different suggestion? I literally have no idea what else could be involved here that would be keeping the system from seeing the battery. Odd thing is, it has twice started powering on while charger was unplugged (fan spins up and low battery warning alert on screen) and I got excited, but then after plugging the charger back in and the laptop booting, there was still a big X on the battery icon each time. I’m not sure if this matters, but after logging into the user account, the battery icon indicator in the taskbar disappears and trying to turn it on just results in the system preferences checkbox unchecking itself immediately. That could be nothing but it’s odd… I’m dying of frustration with this stupid thing ? Edit: adding photos of Logic board for responses below in the hopes that I’m missing something visually (bad cap,resistor etc.), everything looks ok (to me) around the detector cable and is solidly attached to pads. My iPhone 8 is surprisingly blurry when zoomed in but this was the clearest.
Really strange… I did get a new battery detection cable and installed it, now the battery is self-aware, or more accurately, now on speaking terms with the logic board. Seems to be working, charging, cycle counts are readable and charge levels ok. The really strange part is, in this case, only a brand new never-installed detection cable was the solution. I actually borrowed another cable from another A1708 2017 that worked in that system also (which was the 2nd known good cable I tried), when both the donor Batt. detect cables were reinstalled to their respective systems those systems both had no issues reading battery data, at least telling me that both of those worked all along, just not in the problem system. I don’t think this means anything, there is no feasible way the cable itself can have any knowledge of being mated to a system and the cables have no chips or memory as far as I can tell. Still mystified but happy with the outcome. But if anybody else has the issue I had, spring for a NEW $5-$10 battery detection cable to save yourself from the headaches I had.
There is a resistor at the top to the left of the data connector. Check it hasn’t been nudged.
