What is the exact part number on the battery? LIR2032?I ask as if this is a module that already came with an LIR2032, there is a potential discharge circuit on the module. It is meant to charge an LIR2032, but pretty much kills CR or BR versions. There is a resistor you can remove to the battery charge circuit if you want to use a normal battery not a rechargeable.
Avoid running signal traces under the package, unlessa ground plane is placed between the package and thesignal line. All N.C. (no connect) pins must be connectedto ground.
It's worth considering the part about adjacent lines as well. Low power crystal oscillators are very sensitive circuits.Having said that, it doesn't seem to have anything to do with the original question about power drain.
I'm not sure to what extent parasitic losses from the breadboard (especially from the unused INT/SQW, 32KHz, and RST pins) could have affected things; like the traces under the RTC I would expect these losses to affect the ability of the RTC to accurately keep time (they didn't) rather than dramatically affect the battery life.
Yes, to be clear I took a chip without supporting circuitry and soldered it to an Adafruit SOIC-8 breakout board.
Well, the 3231 has a lot more than 8 pins. If you put that on the breakout board you posted a link to, some of the pins would come dangerously close to the through holes. Maybe one of those is making contact.Or did you really mean this one:https://www.adafruit.com/products/1207
Probable dry joint on the far corner, far too much solder everywhere, flux needscleaning off, its drenched! Smooth concave surfaces on the solder are a signthings went well, convex surfaces means too much solder (and hard to seethe joint quality).
Testing adjoining pins with a multimeter will tell you very quickly.