Battery in two different model MacBook Pros no longer recognized

I have both this laptop and a mid 2015 MacBook Pro with retina display. I know they are old, but they have both worked for their intended purposes. I replaced both batteries with IFixIt batteries in April, 2022. They have worked fine ever since. However, in the last couple of days, both batteries are no longer recognized any more and will not take a charge. I have tried multiple different power supplies from different outlets for both, reset the SMC in both, reset the PRAM on both, reseated the batteries on both, power cycled both (many, many times now, hahaha), and nothing works. Additionally, on the 2013 model, the battery will not display in the menu bar and I cannot tick the box in the system preferences to allow it to. I've run coconutBattery on both and in both cases it doesn't detect that a battery is plugged in. I would chalk it down to a fault in the battery if it was just one of them, however, the fact that it happened on two batteries at the same time in two different machines seems a bit strange. One last piece of information: the battery is still displaying on the 2015 model in the menu bar at 0%. When I click it holding the 'alt' button, the computer reports the battery status as normal even though it doesn't seem to know there is one in there - this may be a red herring , though. Any ideas? Thanks!

Hi Dan,

I tried to post this the other day, but must have made a mistake after I wrote it. Anyway, here are the requested screen grabs - CoconutBattery seems to report no batteries are installed. They were installed back in April and both worked until last week. They both disappeared about the same time.

Best,

sean