By "sealed boxes" I'm assuming that you mean that they were in brown cardboard boxes sealed with red and white tape and that they have Lenovo labels with the battery information printed on them? If so, I'd return them for a refund. Even assuming that they have been sitting on the shelf for 3 or 4 years, they should at least charge to some level and be detectable by the Power Manager. Now that I'm thinking about it, there was a battery recall a little while ago which affected the T420 system (among others). Go here to check to see if you have the bad units: https://support.lenovo.com/us/en/documents/hf004122
. I don't know if the recall covered the 55++ battery but I have taken advantage of a couple of other recall campaigns when receiving new or old batteries from eBay purchases. Lenovo does a good job of getting replacements out quickly (at least in my experience).
your definition of "sealed unit" corresponds to what I had in mind. Thanks for the suggestion about check for bad units. I checked the SN of these three batteries at https://lenovobattery2014.orderz.com/
, and they all came up as "not eligible for replacement." The person that I purchased these from has suggested that they need a "firmware" update. I tried downloading and running the “Lenovo Battery Firmware Update” utility (n15fu05w.exe). When I ran the program from a T420 laptop with one of the DOA batteries installed, I received an error message that “Battery firmware update tool has been terminated. The tool was unable to read the battery information due an internal error.” Is there another firmware battery utility that I should be using?