New battery: "The battery's capacity is significantly reduced."
Solution 1:
Cabling can’t really affect the capacity of a battery, so reworking that won’t help.
You’re left with:
- the battery is working just as it left the retailer
- the battery was damaged during the install
- the battery was damaged during shipment
- the logic board has failed
The os clearly indicates you need service. The service tech that sees your Mac might cover follow on questions like:
- What sort of support and warranty did the vendor provide?
- Did the battery you replaced have the identical capacity and warning?